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Archive for March, 2009

Steel Reinforcement, It’s the Pool’s Skeleton!

Sunday, March 29th, 2009

By Tim Long

Have you every wondered why concrete is such a great and versatile building material? Probably not! Neither have most people. Nevertheless, if you’re considering a pool or spa, you should understand a few things about this wonderful material. Why? Because the concrete, specifically reinforced concrete, will be the frame work on which your pool is built. Properly installed it will last for decades. Improperly installed, problems will likely appear in short order, sometimes requiring repair or complete re-installation of the entire project. The elements which make concrete so strong lie inside the concrete and are virtually undetectable once the concrete is installed. It will pay you great dividends to know a little about concrete, before the construction process begins so you know if your project is being built correctly.

The Pantheon in Rome

For background purposes, you should know concrete has been used as far back as Roman times. In fact the dome of the Parthenon in ancient Rome, which is still standing, is one of the best examples of early concrete construction. Early builders utilized concrete because it developed the strength of stone, but could conform to almost any shape they needed. They did recognize its limitation however, in that it could not support great spans without extra support. The early great buildings were limited in height and interior spacing. Walls were supported by great buttresses to withstand the forces of the building domes and roofs.

It was understood very early that reinforcement was needed to properly support walls and other structures. As far back as in the construction of Greek Temples, lead, a very soft but malleable metal, was used to help hold the stones together. Later, cast iron was used. It wasn’t until the 19th century that concrete construction possibilites began to explode. In 1892 Francois Hennebique using steel devloped a system of reinforced concrete. The combination of the inherent compression strength of concrete and the outstanding tensile strength of steel allowed for buildings to take on great heights and expanses.

Pneumatic Concrete - Shot Against the Ground

In pool construction things further changed with the advent of pneumatically applied concrete. Sometimes this is called gunite or shotcrete. But make no mistake, they both are concrete. What makes them great for pools is the way the concrete is applied. Essentially the concrete is forced out of a gun at high velocity. This allows for two things, first that the concrete can be immediately consolidated and compacted when properly applied, two very important elements of strong concrete, in that the concrete becomes a solid body, without voids or hollow spaces which can greatly weaken any concrete. The second thing pneumatically applied concrete allowed is for the shape of the pool to be constructed virtually “formless”. Prior to this time all concrete was poured into forms, constructed wooden boards on two sides. The wet, fluid mixture was poured between the two forms where it remained until it hardened. This required that the pools take on basic, fairly easy shapes to construct in the forming process. Pneumatically applied concrete can be shot directly against the ground or a one-sided form. This greatly simplified the forming process and allowed the shapes to be limited only by the designer’s imagination and the excavator’s skill with the digging equipment.

Along with this new found freedom in shaping pools, also came cost savings. Since pool walls need not be formed so completely, the cost of constructing a pool decreased, creating an explosion of swimming pool ownership across the world. And as pools became more common place, the desire for creativity and expression has lead us to incredible possibilities in shaping your pool.

Steel Reinforcement - Notice the Deforming Marks

It’s the steel properly sized and distributed inside the concrete that gives the concrete it’s incredible strength. Reinforcing steel bars, commonly shortened to “re-bar”, are produced in long “deformed” bars of various sizes. The deformation on the bars refers to the raised markings on the steel, which creates extra surface area and texture to increase the mechanical bond between the steel and the concrete. The steel is laid out in a grid pattern and supported so that when the concrete is applied, the steel will be ”encapsulated” inside the harden mixture. Encapsulation is important since it provides a measure of protection between the elements and the steel, preserving the strength of the steel. In pools, according to the American Concrete Institute, there should be a minimum of 3″ of concrete between the steel and the water. Failure to maintain adequate encapsulation will not only weaken the steel, but the water, will penetrate to the steel, and likely bring particles of steel back to the pool surface leaving a horrible rust colored stain. This reinforced concrete is now able to withstand forces greater than either the steel or the concrete could withstand on its own. The concrete, brittle without the steel, now resists great forces. The steel, easily subject to corrosion from water, is protected by being encapsulated inside the concrete.

When considering the construction requirements for you pool, you should be aware of several vital things:

The steel must be adequately sized. On a typical residential pool, the basic grid pattern is created out of #3 (3/8″ diameter) steel bars. At various points around the pool the size will increase to a #4 (1/2″) steel bar. The beam of the pool, which is probably easier to think of as the top rim, requires the most strength. This makes logical sense, when you consider that the rim of a cup or bowl is usually thicker than most other parts. It is at this point, called the beam, that the pool must be at its strongest. Typically, in north Texas, four #4 bars will be spaced together in concrete thicker than in most other places of the pool. Larger pools or sections subject to great stress may require even larger steel.

Bending Steel to the Pool's Shape

The steel must be properly spaced. On a typical residential pool, at least in the north Texas area, most builders are using a 10″ spacing in both directions, meaning the pattern of steel creates squares throughout the body of the pool, where no square is larger than 10″. At various points in the pool, where additional strength is required, this spacing between the steel will decrease. For instance the beam, being one such stress point, will commonly made up of at least three #4 bars running parallel around the rim with a spacing of approximately 2″ to 6″ apart. This is known as a 30 pound beam, meaning it should be able to withstand earth forces of at least 30 pounds per cubic foot. Four #4 bars in a beam will make up a 45 pound beam, the most common type of beam in North Texas due to our expansive soils, and six #4 bars make a 62 pound beam. Where the pool wall meets the floor, another point of stress, it is common, and usually very necessary, to see an additional steel bar added to the spacing, creating a 10″ x 5″ pattern of steel. The grid, what ever the spacing, will conform to the shape of the pool, moving around corners and over benches and tanning ledges.

A Double Curtain of Steel for the Spa

Freestanding walls require more steel. A pool wall must endure both the force of the water inside the pool pushing outward and the force of the ground pushing inward. Where a wall abuts native, undisturbed soil, due to the ground absorbing part of the load, the strength of the wall need not be as strong as a wall which has no support and must support the entire weight of the water. These walls, known as “freestanding” walls are sometimes required in places such as the wall between the pool and spa, or on a hillside where the ground slopes away from the pool. Internally these walls will require more steel than other walls and may sometimes even require a double curtain of steel.
The steel must be secured. Where the steel crosses other pieces of steel the intersections are secured with tie wire. This keeps the steel from moving out of its required position and more importantly keeps the steel from vibrating when the pneumatic concrete is shot into place. If the steel vibrated this would likely create voids in the concrete, weakening the structure. Steel rods are usually manufactured in 20′ sections. For this reason it is likely that more than one strand of steel is used to make a pass from one side of the pool to the other. Where two sections of steel meet, there must be appropriate overlap. Usually with #3 bars the overlap is at least 18″ and 24″ with #4 bar. Also make sure where the various piece of steel come together that there will be sufficient room for the pneumatic concrete to be applied around and behind the steel. Failure in this area will create shadows, or voids which will weaken the resulting concrete.

At this point you may be wondering who determines if the steel has been adequately sized? Or who determines the appropriate steel spacing? In some cases the builder may feel sufficiently experienced to make such determinations. However, it is my policy to have every pool plan reviewed by a qualified structural engineer. An engineer will use the information revealed on a soil’s report together with the structural requirements of the pool plans and layout the requirements for the steel. It is his job to determine that pool footings are sufficiently sized and placed and that an appropriate steel schedule has been written for the pool.

In summary, it is reinforced concrete that will make possible the pool and spa of your dreams. But make sure that you trust your builder, that he knows and understands the requirements necessary for your pool to last, giving you years of trouble free existance. If in doubt require that his plans be reviewed by a qualified engineer.

Read the previous article in the series “City Permits & Utilities”.

To read the next article in this series, click here: Initial Pool Plumbing & Electrial Work!

To see a short video of steel being laid and tied, click here:

Tags: Construction, Design, Gunite, Pool Decks, Spas
Posted in Construction, Design, Pools, Spas | 2 Comments »

Disguising Details

Thursday, March 26th, 2009

By Tim Long

If you have just spent a large amount of money creating that perfect backyard experience, that last thing you should want is to notice the Details that should remain HIDDEN. You should see the beauty of the water, the color and feel of the stone, the brilliance of the fire reflecting off the water, or perhaps the combination of all these things. But you should NOT notice the necessary, but more mundane aspects of the project, such as the deck drains! Things such as this are required, necessary for quality functioning of the space. But why call attention to them. I have seen numerous installations, where builders have gone to the trouble and expense to add “brass” drain covers to their installations. Brass! I love brass, but the inherent beauty of this metal does not disguise the fact that it covers a drain. Instead it more importantly calls your attention to the drain. Granted a brass cover is better than a plastic drain cover, which are horrible obvious. However, there is altogether a better idea, HIDE the drains!

Hidden Drain Cover

Proper drainage is very important in most installations. It allows for excess water from splashing in the pool or from rain storms to be diverted to more appropriate areas. If no drainage is provided, the excess water is likely to find its way into the pool, carrying dirt from the deck. This can cause extra and unnecessary pool maintenance. The drainage is usually provided by buried drainage lines which are installed with an adequate amount of slope allowing gravity to pull the water and small debris down to areas away from the deck and pool. The drain covers carry the important function of restricting larger debris, which may clog the drain lines, from entering the system.

Drain covers are typically round covers with small, perhaps 1/4″ size, slots cut into the covers. As mentioned before the plastic and even the brass covers rarely blend into the surrounding deck material. However in a recent deck project, I found and installed a new drain cover which virtually hides this detail. The covers are indeed round, but are recessed into the deck and have a center section that can be filled with the same material as the rest of the deck, concrete or even stone, creating a virtually seamless appearance across the entire deck. The only thing that is visible is the small 1/4″ slot that surrounds the center piece. It is as hidden as possible and still be allowed to function as a drain cover.

Filling Drain Cover with Decorative Concrete

The installation of these covers should be considered from the start of any deck project since they must be installed prior to the deck installation. The underground system must be installed first. If concrete is to be poured, the drain covers, installed over the drain pipes must be at the required elevation of the finished deck. Next the concrete or decking material is installed. At this point the same material should be installed into the center section of the drain cover. The photo shows decorative concrete being poured into these sections. In this case the decorative pattern and color must also be applied. This makes the center sections blend into the rest of the deck.

With the installation complete, the drainage covers no longer call attention to themselves or distract from the beauty of the deck! More importantly, you can relax, enjoy your new creation, and pay attention to the details you will really want to see.

For a look another look at this detail, check out my video:

Tags: Construction, Decorative Concrete, Design, Patterned Concrete, Pool Decks, Pools, Spas
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Access for All!

Thursday, March 26th, 2009

Original "Raised" Wooden Deck

By Tim Long

Any good design, must serve its function however that may be defined. Otherwise it is not fulfilling its purpose. I was recently retained by a client, to make a non-functioning space usable again. They had a social area by their pool, but the area, as currently designed was non-accessible to a family member. In its current form the social area was raised above the current pool decking by one step, and was created out of wood. It had been built by the previous owners, so all original design thinking was lost. For the current owners, it was virtually unusable to a family member who needed wheel chair access. Each time a function was held in this area, he had to be lifted, chair and all, above the normal deck grade an onto the wooden area, time consuming and a bit precarious.

The clients wanted the wooden deck area removed to make room for a new area, level with the existing pool deck, and slightly larger in size. They had toyed with the idea of using pavers to accomplish this task, but finally settled on decorative concrete, for its stability and ease of maintenance. They were not sure how large it should be or what new shape it would take. With the layout in mind and ideas from the clients, I went to work.

Deck Perspective Drawing

The design I came up with for the new area would be approximately 1/3 larger than its previous version and for visual continuity would take on some of the same angles used in the pool. The pool was essentially a figure eight in shape, but all the pool angles measured 45 degrees. So the new deck area would have 45 degree angles in several places to blend in better with this original design. It was important that the new deck look as if it belonged, and not as if it were a haphazard addition to the pool areal. The change of material, from an exposed aggregate, of the existing pool deck, to a decorative concrete in a stone pattern was not unusual, since the differing materials would indicate a change in function, from pool circulation to relaxed social area. The stones pattern would be an “ashlar” slate, which is made up of random pattern of squares and rectangles, lined in courses, running parallel to the predominant pool edge of the section. The color choices would be largly tan with some brown and red highlights. In order for the client to see what I had envisioned, I rendered a perspective of design.

Cutting Off the Raised Bond Beam

The first task in creating this new area would be removing all elements that extended above the desired grade, the wood deck and what was known as a “raised bond beam”. This beam was essentially a second row of tile in the area of the wood deck. This second row had been virtually hidden under the wood, yet once the decking was removed, the concrete and tile projected up, higher than was desired. This raised beam which was built on and attached to the beam, or wall of the pool, had to be removed. For this a concrete cutting specialist was brought into the project. The area was stripped of the wood decking and tile work. The cutting crew brought a large saw which was mounted to the pool structure. The saw made rather short work of this 15′ section. It was also necessary to remove several small sections of the pool decking. This was to create a bit of symmetry from one side of the pool to the other, particularly where the new deck was to meet the existing deck. Once the cutting was complete the concrete debris was removed.

New Deck Forming and Reinforcement

Next the ground had to be raised with fill dirt and properly compacted. It is very important to properly compact the new “fill” soil before the new deck is poured. Otherwise the soil will compact on its own over time leaving the new deck work unsupported. This can cause the deck to shift or move with the compacting soil or crack under stress it was never designed to endure. The new deck area was “formed” and reinforced. By forming I’m referring to wood borders which will define the shape of the new concrete deck. Concrete when freshly mixed is in a “plastic” state, thick yet quite pourable. It has to be held in the desired place by these forming boards until it has harden sufficiently to retain its shape. The reinforcement is required to give concrete its enduring strength. Inherent in concrete is a high compression strength, meaning it has great ability to resist compacting forces, such as the force of weight applied downward upon the deck and the force of the supporting ground pushing up on the deck. However if the two forces are unbalanced and produce a twisting motion, for example, non-reinforced concrete can easily break apart. This is why, since the process was invented back in 1892, concrete should be reinforced with a grid pattern of steel rods. The steel gives the concrete the added strength it needs. You will notice the steel is laid out with consistent spacing and is tied together where the the steel sections overlap and intersect. The thickness of the concrete, the thickness and spacing of the steel are determined by the intended use of the concrete and the forces it is expected to endure. In our case steel the concrete was at least 4″ thick with 3/8″ steel laid on 12″ centers in both directions. Additional reinforcing was “doweled” into the existing deck and pool beam, meaning we drilled into this existing concrete and installed steel which is tied to our new deck sections. This doweling will keep the decks from drifting apart over time. But it is important to note that where two sections of concrete meet, an isolation joint will be created. An isolation joint creates a small, but necessary space, usually filled with a flexible mastic material. It separates the two sections allowing for small minute movements in the concrete, caused by the expansion and contraction of concrete. If isolation joints are non-existent or incorrectly installed the concrete will not be allowed to expand properly and can crack or cause neighboring sections to crack.

Adding Decorative Pattern to Deck

You may have noticed from the photographs that the existing deck is cantilevered over the edge of the pool. Many pools have brick or stone that sits directly upon the beam, or walls of the pool, and is commonly referred to as “coping”. The decking is laid up against this coping. However in a cantilevered style deck there is no coping, instead the deck is laid up to and across the top of the pool beam. The look is very clean in appearance as there is no additional visual transition between the deck and the water. However, experience has taught us that in the north Texas area this type of deck, combined with the expansive nature of our soil is problematic. The movement of the decks is so extreme it commonly causes tile around the pool’s edge to become displaced. Many builders will no longer install cantilever decks for this very reason. In our case, we wanted the clean look of the cantilever, but decided to construct the deck in two sections to alleviate the problems with traditional cantilever decks. We poured the “coping” section first. It was patterned the same as the rest of the deck, which disguises our isolation joint. The rest of the deck was poured the next day. Extra effort was takent to make sure the patterns in our decorative concrete aligned across these two sections.

Applying Color and Pattern to the Coping Section

Adding a decorative pattern to concrete involves applying both a pattern to the concrete as well as a color. The pattern is applied to the concrete after it has been poured and begun to harden, but before the concrete is no longer malleable. The timing is critical and requires experience to get it right. In our case, since we poured the deck in two section, at two different times, the pattern had to be applied twice, once to each section. The most detail was applied to the front face of the coping section, since this area presented itself first to someone walking into the are. This section required additional forming, made out of styrofoam in order to achieve the consistent rounded edges we desired. In the photo you can see that once the styrofoam form was removed, a top coat was applied to the concrete that had been hidden by the form, in order to apply the pattern and coloring to this section. It is detailed work, but the finished product is worth the effort.

Applying Pattern to the Concrete

The second section, being much larger than the coping section, required more effort to apply the pattern. One of the secrets to good decorative concrete, is to have a number of patterns. If too few of these “stamps” are available, the eye begins to pick out the repetitions in the pattern and the project risks calling too much attention to itself. Another secret is the artistic experience of those who apply the pattern. In our case since we were using an ashlar pattern, which is made up of different combinations in size and shape, smaller and larger, rectangles and squares. It takes skill to combine these shapes, covering the area required, but using visually pleasing combinations. Although color has been added to the concrete mix an additional “release” color is added, after the patterns have been applied. This release color will give added visual depth to our project.

Finished Deck with Color Highlights and Sealant

After a curing period, approximately 2 weeks, the final color highlights are applied to the deck. These highlights are what allows the deck to take on a more natural appearance. No decorative concrete will look “exactly” like natural stone, but with a skilled applicator it can take on an amazing appearance, which will rival natural stone, given concretes easy of installation and maintenance. You may have noticed that as we neared completion some darker blue stone colors were added to match the few blue bricks of the house. A mastic joint was added between the coping and deck sections. This rubberized mastic was topped with a “decorative” or colored sand to allow it to blend into the deck. Finally a concrete sealant was applied to protect the concrete. This sealant will have to be re-applied every 2 to 3 years.

With the work complete, the clients can now enjoy a more usable social space, with a quality material, which is both visually pleasing and integrated into the setting. More importantly, access to this area is now easier. With no elevation changes, it will be hassle free, for all the family members to enjoy dinning and relaxing in their new pool area.

Tags: Construction, Decorative Concrete, Design, Patterned Concrete, Pool Decks, Pools
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Excavation - The Big Dig!

Tuesday, March 17th, 2009

By Tim Long

Marking the Pool Deck Edge

After the building permits have been issued, the utilities located and re-routed if necessary, the next step is the excavation process. This is one of the most important stages of your pool’s construction. You must realize that once a hole has been dug, any changes to the location , its shape or its size will likely cause an increase in the cost of the project. That is why most designers and builders go to extra measures to insure that the location, shape and size are clearly confirmed before the ground is broken. Even though I present plans and perspective drawings, which give good ideas of the pool’s future appearance, most people can not visualize completely what the pool will eventually look like. I find it helpful to “paint” the pools outline in the grass, before the excavator has even arrived. This paint, far from permanent, helps most people see the pool in its proper context, before any digging begins, which is far more permanent. With the paint marks, most people will get a better feel for the pool’s size and orientation. It is here you should be asking questions, such as but not limited too the following:

Will you be able to see the pool from inside as you want?
How will I move from the house to the pool?
Where is the pathway to be located?
Is there enough room to move around the pool?
Is there enough room to lounge on the deck or in the pool’s lounging area?
Will the sun light strick the lounging area as you want?
Is there enough shade where you want?
Will the children be able to play as you intend?
Is there enough room to entertain as you envision?

At this point changes can be addressed rather easily. The skill of the designer will also pay off here, as he should have been able to anticipate most of your question.

Heavy Equipment

Once everyone is pleased with the layout, the digging can begin. Where possible a full size excavator can be used to remove any unwanted objects and dig the pool to its proper depth. You should be aware that the equipment needed to build your new pool, particularly the excavator, can be quite large and make quite a bit of noise. The equipment and personnel need to run it will take up space, inconvenience your neighbors and destroy landscaping between the staging area and the location of your new pool, including fences and other objects in the path of the equipment, which, in the case of the excavator, needs at least an 11 pathway for clearance. Trees and shrubs in the area which are to remain should be protected. This protections should extend to the “drip line” of tree. Many think if the tree trunk is protected the tree will survive. This is not necessarily the case. As large equipment moves acrossthe roots of trees, the soil can become compacted making it difficult or impossible for the tree to survive the stress. Talk with your designer and builder, or even to an arborist, as to what measures are necessary. It should also be part of the planning process to also repair the grasses, landscape, pathways, irrigation lines and fences that will be unavoidably damaged.

Debris Removal is Quick with an Excavator

Care must be taken to reduce traffic problems and inconveniencing of those who live around you. Many cities have limitation on working hours, mandating most work to begin after 7 am. Fortunately most of the better pool contractors understand the inconvenience the experience can cause and do their best to limit the disruptions where possible. The largest piece of equipment used on the average pool is known as the full size excavator. It is an impressive piece of equipment and can remove the dirt for most pools in the space of a few hours. Hard or rocky soil can lengthen the process, particularly if access is limited and the builder is required to use smaller digging equipment. Rocky soil can also increase the cost of the excavation. Many pool builders build into their project cost certain allowances for the excavation portion of the pool. “Overages” beyond the anticipated cost will likely be charged to the owner. This is why, among other things, my recommendation, as written in “It Begins with Design”, is that a soil’s analysis be performed to determine the type of soil and the suitbility of the soil where the pool is located, prior to the excavation process. These reports should indicate not only the presence of rocky soil, but also if extra measures are required to support your pool If a soils report was not undertaken, as a minimum, having a soil engineer observe the soil conditions once the pool is excavated, should at least be accomplished. This is rather cheap insurance to make sure the proper structural requirements necessary to preserve the pool, in its present location.

Digging the Pool

Once the pool excavators are finished, you should be able to see the most prominent features of your pool. The actual pool will be slightly smaller and shallower because you must allow for the thickness of pool structure. Walls separating the spa from the pool and steps, in most cases, will be formed completely out of reinforced concrete, and may not be visible at the point. However you should be able to notice benches and lounging areas and the general location of the spa. In some areas of the country, particularly in coastal areas, where the water table is high, the pool has to be completely “over excavated” because the hole will not retain its shape, collapsing in upon itself. Where the soil holds its shape, forming boards will be placed above grade and in special areas to allow the concrete to be “shot” against it. (More on this subject later.) But in the areas where the walls collapse, the over excavation allows for the walls to be formed out of wood, where the concrete will be eventually attached.

Once the excavation equipment leaves the yard, the hole is typically exposed, since fencing material has usually been set aside to allow access. Generally laws dictate some form of temporary fencing surrounding the newly formed hole to prevent accidents. However the first major step, and typically the most dramatic, has been completed.

Read the previous article in the series “City Permits & Utilities”.

Read the next article in the series “Steel Reinforcement, It’s the Pool’s Skeleton!”.

Tags: Construction, Pools, Spas
Posted in Construction, Pools, Spas | No Comments »

City Permits & Utilities

Monday, March 16th, 2009

Dallas City Swimming Pool Permit

By Tim Long

After your pool has been designed, but before any construction begins, permits from the local authorities must be obtained. In most locations there will be some governing authority which oversees residential construction. The purpose of these authorities is to require that your plan will be up to the standards of the community. These requirements are in theory supposed to eliminate substandard construction practices and insure community safety and property values. However in practical terms its is most important to confident that your builder exceeds these minimum standards. The authority will require inspections at certain crucial stages of construction; typical after the steel reinforcement and electrical bonding and initial plumbing have been completed, but before the concrete has been applied; after the electrical and plumbing work was been performed and after the safety items have been installed, such as barrier fencing, but before the interior finish has been applied. Other inspections may be required depending upon the items being constructed.

You should know that these requirements are constantly changing. As an example, at this time, March 2009, we are seeing Federal requirements governing safety in pools, specifically the Virginia Graham Baker Act, being implemented. This law was designed, among other things, to reduce the possibility of suction entrapment on pool drain covers. Since the law is Federal it will take time until the local authorities codify such laws into community requirements. It is important that the designer and builder be well informed of all the requirements to insure that the most current thinking has been used in the construction of your pool.

Typical Plat

When applying for a building permit for you pool, a fee will be required along with copies of the building plans. These plans will be reviewed to determine that the plans conform to the authoritie’s requirements. Your designer or builder should be aware of any requirements in your area, but as required, be flexible enough to adapt the plans to the requirements. Many of these requirements can be seen on your “plat” or scale drawing which visually describes your property. The plat, which you should have obtained when you purchased your home, should show the required “set backs” or “utility easements”. These are areas on your property on which you can locate substantial structures. “Variances” or exceptions can sometimes be obtained in certain circumstances to build in these areas, but many times these easements protect access to utility services which run throughout the community.

Excavation of a Pool

After the plans have obtained approval one further step needs to be completed before construction begins. In many areas the utilities, such as sewer, electrical, telephone and others, are buried in your yard. If excavation begins on your property and these utilities are damaged, it is possible that the homeowner will be held responsible for the cost of the necessary. These utilities must be identified before excavation. In many areas the utility companies, in an attempt to reduce or eliminate these accidental damages have set up organizations for the purpose of identifying these underground services. In Texas, for instance, there is a non-profit organization known as “TESS”, Texas Excavation Safety System. The builder should simple call TESS at least two days prior to excavation. A TESS member company will mark the necessary underground lines to help prevent any utility damage.

Gas Line Re-routing

If it is discovered that utilities lie in or near the placement of the pool or other new amenities, the utilities may need to be moved. The cost of such possible movement has to be accounted for when planning your new pool. However such cost are usually nominal when compared to the cost of the overall project.

Read the previous article in the series, “It Begins With Design”.

Read the next article in the series, “Excavation - The Big Dig!”.

Tags: Construction, Design, Pools, Spas
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It Begins With Design!

Thursday, March 12th, 2009

By Tim Long

Pool with Spa

If you are interested in building a pool, spa or water-feature one of your first consideration should be its design, what size, shape, how it will look and feel in your backyard. This involves understanding the many factors such as thefeatures you wish to include and where you want them located. It also includes knowing how much you want to spend.

This process typically starts with a designer. Most people are not accustomed to design work and need assistance in this area. Fortunately, most pool companies provide this service as part of their company’s building program. Unfortunatly, for many companies, the designer is nothing more than a salesman, who is more interested in telling you what type of pool he can build and what you need in your yard.

A good designer, by contrast, will listen and incorporate your desires into the process. He or she will start by exploring the area to be used and by asking you many questions. Of foremost interest is how you intend to use the space. If a “designer” presents you with a design having never asked this very important question, run! If he is not interested in how you intend to use the area, he can’t tell you what you truly need. Most people have at least general ideas about the pool they want, having seen pools at their friends, relatives or even at favorite resort. These ideas may include many specific features that they have seen and appreciated in their travels. However, as trends appear and new innovations develop, their may be many wonderful possibilities, ideas that you might eagerly embrace, if the designer suggest them having first asked that one simple question.

I mentioned that a designer must listen. But I mean to suggest something more that just passive hearing. The designer must understand your wishes, respect them and incorporate them into the plans. You can’t imagine the number of times I have heard clients indicate that the designer heard their desires, and then returned with pool plans that bore no resemblance to their ideas. That does not mean a designer will always incorporate everything into the plan. Sometimes that is not possible or even prudent. A good designer should make recommendations that sometimes may be inconsistent with the client’s wishes. This is particularly important if the client’s desires have some hidden conflict which may not immediately recognizable. At times the client’s desires will conflict with the designer personal tastes. However, a good designer knows the difference between what is a potential design conflict and simply a matter of taste.

Further, the designer should not only be aware of current needs, but inquire as to future considerations. Knowing about intended family additions, for instance, may allow the designer to suggest additional safety devices, perhaps not needed now, but plans could be made to allow the future implementation easier. Another example is where a total plan would include not just a pool, but an outdoor kitchen as well. Though budget constraints require these projects to be spread over time, it is important to keep future planning in mind. Some future project may be less expensive if they were combined, at least in part, early in the project. For example, in the case of the desired future kitchen, it may be prudent to lay the gas line, before the pool deck is placed, even though it may not be used immediately. That would far less expensive than having to break the deck to install the gas line later.

Light On Water

There is a danger here that you might become side tracked. It is easy to become so focused on specific ideas and plans that you forget to consider the complete picture of your yard. A thorough design is one that looks at the entire backyard experience. You may think you are just buying a pool so the kids can play after school. But you are in reality creating an experience that is not just to be physically enjoyed, but to be absorbed both visually and emotionally. The designer should help you think in these broader terms, seeing how your pool relates to these various considerations and view your pool as it relates to the entire yard.

However a good designer, also concerned with the details, will discuss the colors and textures of the materials found on or in your pool. Each of these things will have great bearing on the experience. Some colors are warm and inviting while others are colder and more ahloff. Some materials are smooth to the touch while others are rougher, each giving a different and distinct experience.

The differing materials which will make up your pool will meet, creating joints at various sections, such as where the tile and coping meet or where the coping and deck meet. Each of these meetings or joints must be “detailed”. Details should be planned so that where the materials meet it has the proper look. These things do not happen by accident. It is in paying attention to the details that will make a simple project extrodinary or conversely make an expensive project look sloppy. Inquire of your designer about such details. If he is good, he will know or at least discuss the possibilities. You may not be a designer, but on this point, trust your instincts. The best designs are usually collaborations between a good designer and an involved client. If you don’t work well with a designer, get a new one.

The Relaxing Sound of Falling Water

Sound will also be a design consideration. I have seen many waterfalls placed on pools. They were probably created at the client request. However, because the design or lack of it, the noise from the waterfall was so intense it interfered with conversation around the pool. Instead of being a relaxing sound, it was a noise that had to be eliminated. There are many waterfalls that have rarely been used after just a few months or even weeks because of the sound issue alone. Talk to your designer. The sound of water moving is very relaxing, and visually captivating, but must be planned properly. Consider this. Water is its most quiet when it is at rest, meaning at balance with gravity. At the other end of the spectrum, where water is far from rest, it makes a violent crashing sound particularly when it falls from great height or with great volume. The most relaxing sounds come from water which is almost at rest. Since the sound is always a combination of height and volume, it seems prudent that they should be considered in the design, before construction. The height is difficult to change once the pool has been completed, water volume should be adjustable with proper valving.

Don’t forget lighting, in your pool and in your yard. Paying attention to lighting can greatly enhance and extend the hours you spend outdoors. Lighting should be considered carefully. Consider getting assistance from a lighting specialist. However the designer can help you determine what elements in your yard should be illuminated for both beauty and function. When it comes to pool lights in particular, I must address one of my pet peeves. For many years the lights have been station directly below the diving board, which in many cases pointed the light directly at the house. Even now, with many, if not most, pools being built without diving boards, the lights are still positioned so that the light source is evident from inside the house. It is the goal of good lighting technique to eliminate where possible the views of the light source from the main viewing locations, which means the lights of the pool, should be point away from, and not toward the house.

One other issue should be addressed in the design phase. It is my recommendation that a soil’s analysis be performed to determine the suitability of the soil where the pool is to be located. This testing may have been performed by the builder of your home. If so, it is likely that this earlier soil’s report will sufficiently reveal the soil condition where your pool is to be located as well. There are many pool builders who do not suggest this kind of testing. However it is important. Consider that the pool, when complete is likely to hold thousand’s of gallons of water, which weighs a considerable amount. You could calculate almost 8 pounds for each gallon, not including the weight of the structure itself. In many areas of the country the soil, in it’s natural, undisturbed state, can bare the weight of this pool. However, in other areas this is not the case. Even in good areas, if the ground has been previously disturbed, and fill dirt has been used to landscape, for example, the strength bearing capacity of the soil many have been weakened. In these conditions, and in conditions where the soil does not naturally have the sufficient bearing capacity, extra measures must be performed, to ensure the integrity of the new structure. In some cases, the engineers will order piers to reach down to good solid soil below. In other cases, over excavation is required to remove “bad” soil, then good soil is brought on site and compacted into place. Whatever measures are required, it is the soil test that will allow the proper steps to be taken. It may cost more to have the test completed, and if necessary, the extra steps that are a result of the test will certainly cost more. Yet the cost of repairing a pool that is no longer level far outweigh any initial costs! A good designer and builder will confirm this information and highly recommend this course of action.

In summary, find a good designer, one that asks many good questions, incorporates your ideas, pays attention to all the details including, but not limited to color, textures, materials choices, sounds, lights even soil conditions. Be ready to ask many questions of the designer, be involved, help him make the choices that best suit all your needs. Enjoy the process. But most importantly remember that he is not just designing your pool, he is designing an experience!

Read the next article in the series “City Permits & Utilities“.

Tags: Colors, Design, Details, Pools, Spas, Textures
Posted in Construction, Design, Pools, Spas, Water-Features | No Comments »

Shot-Crete, Gunite what’s the Difference?

Monday, March 9th, 2009

By Tim Long

There is a lot of confusion over the difference between Shot-Crete and Gunite and which process should be used for your swimming pool or spa. Many pool builders will argue why the process they use is better than their competitor’s without really understanding the differences themselves.

If you were to research the American Concrete Institute or the American Shotcrete Association, you would find that both terms refer to the application process of good old fashion concrete. The concrete mixture travels from an applicator’s truck to the site via a large hose. Air pressure is applied and the mixture is “shot” into place at speeds approaching 200 mph. This is extremely important! Why? Because it is with the forced placement of the concrete that either process gains it’s merit. Any concrete placement should be “compacted” to remove voids, air bubbles that weaken the strength of the eventually hardened concrete. For concrete that is poured, applicators will use a variety of methods, tamping, vibration, etc, to achieve compaction, but no process by hand can compare to the compaction that can be achieved by the pneumatically applied shot-crete or gunite.

Why the two different terms? Shot-crete was invented by Carl Akeley, who received a patent on the precess in 1911. Originally the concrete mixture, which is made up of cement, aggregate was pumped through the hose dry. At the nozzle water was added along with the air needed to project the mixture. Today this process is now known as “dry-mix”. In the 1950’s it became possible to mix the water first, then pump the “wet mix”, only adding air at the nozzle. This was important for two reasons. The amount of water could be controlled more closely and the aggregate size could be larger than just sand, i.e. pea-gravel. (Note: the amount of water in concrete is the single most important factor in determining the strength of concrete). Today shot-crete has become a generic term which refers to both processes. However some in the pool industry use the terms shot-crete to refer to “wet-mix” and gunite to refer to “dry-mix”.

Which is better? That’s a hard question to answer, because it depends upon several variables. In theory, dry-mix should be stronger. The key is adding only enough water for proper “hydration”, the process which causes the cement to bond to the surrounding aggregate, and not a bit more. If the nozzleman is “certified” by the American Shotcrete Association, he has been thoroughly trained and tested on how to properly control the amount of water being added in the dry-mix. However, if the nozzleman is less skilled, he may add either too much or too little water, either extreme greatly weakens the future concrete. In the “wet-mix”, the moisture content can be more closely controlled, eliminating this as a variable. It is true that the moisture content is greater than can be achieved with properly applied dry-mix, but the possibilities of too little or too much water, have been eliminated.

There is also the question of “rebound”. Rebound refers to the aggregate, which bounces or deflects off of the receiving material and lands in areas other than intended. When the small piece of sand is in mixture, it is combined with the moisten cement and if properly placed will added strength to the structure. If on the other hand, bounces off something hard, such as the wooden form or a piece of the steel reinforcement, the cement is likely to adhere to the hardened surface, but the sand, now mostly stripped of the binding agent falls elsewhere. This rebound, must be gathered up and removed, not allowed to become part of the structure. To do so would be to create a weakened structure. It is known that the dry-mix process creates substantially more rebound than the dry-mix process. If the applicators are skilled in the process this deficiency can be overcome.

In summary, gunite or the dry-mix should be stronger, but the margin for error is too great in my opinion. Having seen too many failed dry-mix applications in my years of experience, I much prefer to use a shot-crete or wet-mix process in the construction of my pools and spas.

Here are some pictues of the shotcrete process and a short video of shotcrete being applied.

: Nozzleman builds the Pool Wall

: Nozzleman begins the Spa Wall

Tags: Construction, Gunite, Pools, Shot-crete, Spas
Posted in Construction, Pools, Spas | 2 Comments »

Glass Water-Feature

Wednesday, March 4th, 2009

By Tim Long

I was driving to meeting at a client’s home today and came across a modern home with two distinctive Glass Water-Features. The glass had a green cast in a wedge shape and appeared to have an undualting surface. As the water bubbled up at the top, the narrowest part of the wedge , it cascaded down in the groves of the surface. The twin features guard the front entrance.

I loved the features even though they appeared misplaced in front of this home.

: Dual Features Guard the Entrance

: Water Cascades down an Undulating Surface

Tags: Art, Fountain, Glass, Water Feature
Posted in Art, Water-Features | No Comments »

The “Modern”, Art with Water

Wednesday, March 4th, 2009

By Tim Long

The Modern Art Museum in Fort Worth, Texas shows exactly what “water” can do in the hands of a master. Todao Ando, renowned Architect, achieved stunning visuals integrating water seamlessly into his creation. The building is as much Art as art it contains!

I loved his uses of bare concrete, polished, but unstained, simple, yet elegant. You can observe the imprint of the forms in the concrete. More over the polished surface reflects the wonderful play of light in the building.

Visitors are treated to buildings seamlessly integrated with the water around their environment. Visitors to the cafe, sit and eat with water lapping just outside the glass wall. The “lake” is actually a man-made and controlled body of water, which is actually quite shallow, approximately 6″. The bottom is paved with what appears to be dark gray smooth stones, which help to darken the water color, and enhance the lakes reflective capacity.

For more information visit the Musuem’s web site http://www.themodern.org/index.html.