In this industry populated by people, who have learned their craft by the seat of their pants, or from others who did the same, it is nice to know there is a place where quality workmanship and industry standards are actually taught. Dave Boyd, my business partner, and I recently attended such a school, so that when were are asked why, we would not respond, “that’s just the way we always have done it”.
David Tisherman and Skip Phillips with student
The school was taught by the renowned Genesis 3 Design Group. It is a joint effort by three of the finest pool designers in the world, David Tisherman, Skip Phillips and Brian Van Bower. It is the only pool and spa construction school in the United States that is accredited by IACET, the International Association for Continuing Education and Training. Genesis efforts, in offering this course as well as a number of other courses, that range from the technical aspects of the pool industry to designing the most artistic pools in existance, should be lauded. As a by product of their work, they have also created a network of designers and builders who are continually pushing the bar, setting the standards higher and higher!
In class with civil engineer, Terry Brannon
Having been in the industry for almost 20 years, first as a service professional, then as a pool renovator, designer and builder, I have seen first hand the poor standards most pool companies hold for themselves. It is a said fact these companies are not even aware of the standards set by fine organizations such as the American Concrete Institue or the Ceramic Tile Institue of America, let alone make their project specification adhere to their basic guidelines. Furthermore, I have previously attended certain trade association’s classes, and have been far less than impressed. With some associations, it seems they are more concerned with giving out ludicrous awards and patting themselves on the back, than in the delivery a quality product. It’s no wonder the pool industry has such a bad reputation.
Celebrating Success
Wanting to establish our company as above the average, we decided to complete the requirements of this course, which was followed by a thorough examination, given according to IACET standards. Both Dave and I learned a significant amount of information and were able network with a number of like-minded professions. More importantly, we both passed the examination. In the category of “tooting my own horn”, I was able to bring home the all time best examination score, and be quite proud of it!
By Eric Herman (written for Luxury Pools Magazine)
There was a time when swimming pools were relatively limited in terms of their aesthetic bandwidth. They were either kidney, rectangular, or lazy-L shaped, with white plaster, blue waterline tile, bullnose coping, and—if you were lucky—maybe tile mosaics depicting fish.
These days, however, that has changed completely. Swimming pools and the landscape elements that surround them can now be seen as a rapidly expanding architectural art form with a myriad of features, colors, materials, shapes, sizes, functionality, and stunning sculptural beauty.
As a homeowner considering this spectrum of creative possibilities and lifestyle benefits, the first thing you should know is…READ MORE
In our previous articles we discussed the design and layout of the pool, its excavation and steel reinforcements as well as the initial plumbing and electrical work. All of this work has been leading up to the single most important construction component, the shell of the pool, which surrounds the body of the pool. It is made of pneumatically applied concrete, shot at high speeds, encapsulating the reinforcing steel, to give remarkable strength. It’s quick to install, versatile, in that it can conform to almost any shape and compared to poured in place concrete is very economical. Yet without proper technique being applied at the time of the shot, the entire future of your pool will be problematic.
With all the preparatory work out of the way, the day has arrived when your new pool will be shot. The process is referred to as “shooting” because the materials are literally blasted into place at high velocity, over 100 mph, which is good! This “blasting” is part of the reason that the shell can develop such great strength. Other contributing factors will depend upon the type of shooting that will take place. There are two types. Although the names have been used interchangeable by some in the industry, which causes much needless confusion, both types are technically known as Shot-Crete or pneumatically applied concrete. With either type, the crews use air as the primary driving force which places, then compacts and consolidates the concrete mixture. The differences are that some crews use a dry-mix, commonly referred to as “gunite”, which is delivered from the trucks, forced through large hoses by air pressure, then combined with water as it leaves the hose nozzle. The other type of crew use a “wet-mix”, commonly referred to as “shot-crete”, which is combined with water prior to being pumped by a concrete pump through the hose, then is forced by air from the hose nozzle. For more information on the differences, read my article “Shot-Crete, Gunite what’s the Difference?”
Shotcrete Truck Setup
As the crews arrive, you will notice they are accompanied by several large trucks. The number of vehicles depends on which type of crew has been chosen. A wet-mix crew will arrive with at least a concrete pump and a large air compressor. They may mix the concrete on-site, which will require a vehicle to hold the raw concrete, another the aggregate, usually sand and pea sized gravel, and a mixing unit to combine these items with water. This is commonly done in area that experience high temperatures and are too far from a local concrete batch plant. As you may know, concrete, once mixed, must be placed within 90 minutes. So on-site mixing is sometimes their only option. A dry-mix crew will have a vehicle to hold their dry mixture and of course a very large air compressor. The larger compressor is required because the air is not only used to force the mixture into place, but to also move it through the hose. By contrast the wet-mix is moved through the hose by a pump, not air.
Below is a video of a wet-mix truck in place:
With the truck ready, the crews prepare the pool, confirming several key factors. First the pool must be level. Hopefully the previous crews properly leveled the work, the wood panels which outline the pool shape. If not, last minute adjustments must be made.
Second, the elevation must be correct. This measurement establishes a necessary reference point so that after all the work is complete, coping, tile, deck, etc, the finished product is at the appropriate level in relation to the house, or other buildings. Once the concrete has been set, “out-of-level” and “elevation” adjustments are much harder, if not impossible to make.
Third, the forms and steel are checked for sturdiness or rigidity, neither must be allowed to shake or otherwise move as the concrete is being shot. Vibrations and movements prevent the concrete from properly attaching to the steel and possibly create hidden voids, or pockets of air, which will weaken the structure. Insist that your builder provide adequate form work. A weak form will only hurt the process. If a spa is part of the plan, make sure the builder installs a form board between the pool and spa. Do not let them simply hold a “peg” board, or have it wired in place by bailing wire to the reinforcing steel. A solid form should be built. Once the wall which separates the pool and spa is shot and partially set, the form can be removed before the rest of the spa is shot. Failure to do so might mean a weakened mixture and voids behind the steel.
Fourth, they will confirm the thickness of the completed beam. Here the crews will confer with the builders plans to make sure the top of the pool wall, the beam, will be as thick as designed. Typically this is about 12″ wide. The importance of this cannot be overstated for two reasons. First, the beam must be sized as designed to allow for the later installation of finish stone work, and the allow the appropriate integration with any new decks, etc. Second, and no less important, the beam, and not just the beam on this point, must be wide enough in all places to properly “encapsulate” the steel. As we have all observed steel will rust, an normal process of oxidation when air, steel and water meet. Rust, although rarely good, is very bad in pool steel reinforcement. Particularly if the rust finds its way into the pool and shows itself as a dark red stain on the pool wall. In order to reduce and hopefully eliminate this process, the American Concrete Institute specifics where concrete is exposed to earth or water the steel should be encapsulated by at least 3″ of concrete. Unfortunately I have seen problem pools where the steel has only 1/2″ of concrete between the steel and the water. This problem can not be corrected later, only managed. It is a costly and avoidable problem, if the pool is shot correctly.
Setting the Guide Wires
To aid the crews as they are shooting, they typically install fine guide wires. The attached photo shows just such a wire, although the wire, being about the thickness of a piano wire is hard to see. Unlike poured in place concrete, which has forms forms on both sides, to contain the fluid concrete, shot pools have forms on only one side. Newly shot concrete is just shot is stiff enough to maintain its basic shape, so two sides are not needed. However, the guide wire helps the crew see where the “other” side of the concrete needs to be.
Partitions to Reduce Overspray
Other preparatory work includes placing screens to help prevent concrete over-spray from reaching the home or other structures. Concrete over-spray on a home would not be a good thing! There should also be a decision on what to do with the rebound and trimmings. Rebound is the term for the concrete mixture that bounces off during the shooting process. It is important to note that the “bounced” mixture is concrete poor, meaning it is usually the aggregate, sand, that bounces, most of the concrete that was part of the mixture will stick, making the rebound mostly aggregate. So rebound must not be reused. It should be collected and discarded. As a point of interest the dry-mix process always generates more rebound than the wet-mix process. A small amount of rebound is usually not a problem, but a large amount will have to be removed from the site. The mixture, though concrete poor, will still harden, and have to be discarded.
Troweling the Wall
The term trimmings refers to excess concrete, more being shot than is actually needed the crew will trim the concrete to the required shape, letting the trimmings fall. Trimmed concrete can be reused, as it is not concrete poor, however, it must be properly compacted and consolidated into place. Most crews find places in the floor for the trimmings. It is not recommended that trimmings be used in the cove, where the wall meets the floor as this is a structural stress point. This however is where trimmings typically fall. This requires the trimmings to be moved to a less stressful place on the floor.
Below is a video of a pool wall being trimmed:
With all the prep work complete the shooting begins. The long hoses, running from the truck to the pool, terminate at a nozzle, which the crew member, called the nozzle-man, aims the hose, directing the concrete flow. He begins at the cove, base of the wall and floor. The extremely important area, must be solid and well shot. The concrete is built up from this point making the walls, benches and other components. The floor is usually the last place to shoot. Sometimes the process will be stopped as the crews moves between the main pool and the spa, fountain or other structure. Always the nozzle-man maintains a flow at downward angle, moving back and forth building up the concrete toward the final shape.
Finished Shell
As mentioned earlier regarding trimmings, the concrete is built up to a level greater than needed, then trimmed back to the desired shape. The process requires patience and an ability to see shape of the final product. All the internal components have to be shaped, the steps, benches, love seats and shallow lounge area. In addition the pool fittings, where the plumbing penetrates the wall has to have special attention. At each location an indention is shaped around the protruding pipe to provide room for the “fitting” which will be installed later. The lights, skimmers and main drains will have similar attention. Finally you may notice one or more “weep” holes, voids in the concrete where ground water can move if excessive rain occurs before the pool is completed.
The entire process for a small pool should only take a few hours, obviously more for larger one. Large commercial projects can take several days. Prior to the shell, the shape of the pool can only be imagined, based only on the design drawings and the designers descriptions. Now, the shell having been shot, the pools shape becomes clear. One step closer to a completed pool!
In our previous articles on pool construction we have discussed design, required city permits, excavation and steel reinforcement. We are almost ready for shooting the pool shell. However we most consider that some tasks required in the construction of must be at least partially performed before the pool shell is built, namely the plumbing and electrical work. Both of these tasks will not be fully complete until much later in construction process. Yet where either of these tasks will penetrate through the pool wall, the must be laid before the shell is installed.
Skimmer Plumbing
The easiest explanation of the plumbing is built on the understanding that the water in the pool completes a circuit, which is known as the hydraulic system. It must first be pulled from the pool, filtered, heated if desired, perhaps even treated chemically, then returned to the pool. This process begins with the water being extracted through the skimmers and the main drains. The skimmers which mounted at the water level are designed to catch leaves and other floating debris which is collected in a basket. It is advisable to have more than one skimmer installed in your pool, particularly in environments with lots of foliage or on larger pools. Better pool designers and builders will insist on at least two skimmers on every pool and increase their number as the situation warrants. The exception to this is on pool designed with either a “vanishing edge” or a “raised perimeter overflow”. The vanishing edge pools have at least a portion, usually an entire side, where the water spills over the wall of a pool and into a trough or catch basin. Raised perimeter overflows are pools partially lifted out of the ground. Here the water spills over the entire perimeter of the pool, usually into a hidden trough which surrounds the pool. Both of these types of pools offer dramatic visual effects and usually have no skimmer. This is because the trough or catch basin often acts like a huge skimmer. These pools stay remarkably clean!
Main Drain Plumbing
The main drain, which is a misnomer, is currently the source of much saftey discussion. It really should not be called a drain since it does not allow you to drain your pool. Neither should it be considered the main source of water for your pool equipment, in that the equipment should only rarely receive all its water from these drains. Technically these devices are referred to as “suction outlets”. It is vitally important that the hydraulic system of any pool be designed with care. Recently congress passed the Virginia Graeme Baker Pool and Spa Safety Act. This law purpose is to reduce the danger of these outlets by requiring outlet covers pass strengant testing requirements and that outlet placement meet certain standards to reduce the likely hood of someone becoming entraped by these outlets. However there is no requirement that a pool actually have these suction outlets. Constructing a pool without them altogether will more than just lower the possiblility of a suction entrapment, but will compeletly eliminate it! The photo pictures placement of these suction outlets as currently required. If you look carefully you will notice that the installation has altered the steel layout which will have to be corrected before the shell is shot.
Wall Plumbing
After the water has been filtered and otherwise treated, it is returned to the pool via the returns fittings attached to plumbin which extends through the pool shell wall. Prior to the shell construction, the plumbing for these returns must be placed and secured into position so that they can not be moved as the shell is placed.
Electrical Bonding
A similar process must be completed for the electrical work. Codes require that the steel be tied electrically to the electrical system through a bond, which is a wire that runs from the pool equipment and to the pool structure and is tied in several places directly to the stell reinforcement of the pool. Since most pools are constructed with an underwater light the conduit for the light must also be installed at this time.
Later the more plumbing and electrical work will have to be completed. But with the inital work complete, specfically where there work extends through the pool wall, the pool is now ready for the next step, the shooting of the pool shell!
To review a FAQ (frequently asked questions) Report prepared by the Health Department of the State of Texas regarding the Virginia Graema Baker Pool and Spa Safety Act - Click Here!
It should be noted that not everything must be the same. Sometimes even simplest changes, such as the direction of the tile can make all the difference in the world. Doing so may add visual interest by emphasizing a new direction for the eye to follow. On a recent project we used a diagonal placement of tile to achieve a stunning look over what was a dated and overwhelming feel of the brick!
Brick can be a wonderful construction material, but in this case, the builder used too much brick. In dealing with an natural elevation change present in the yard. The builder created a wall, raised bond beam, to retain the soil of the yard, which sloped toward the rear entrance of the home. This raised area was now home to a spa, itself raised slightly, and a small entertaining area. This area space is accessed by a series of steps to the left of the spa. The wall began with the steps, ran underneath the spa and extended to the far side of the pool where it similarly descended back to the elevation of the home. For all of this the builder used a red brick, both as coping on the pool wall and as a face to the wall itself. The only exception being a vertical band of tile below the spillway of the spa. The effect of this much dark brick was to overwhelm, putting the entire backyard out of balance.
In approaching this project, our client asked us to update the pool’s overall appearance, especially the brick wall. To do so required numerous visits to various material suppliers until we found a coping treatment and tile selection that matched the clients taste while lightening the pools appearance.
After much searching and deliberation, we finally settled on a 6″ x 6″ light tan and gold tile, which came with wide variation in color for the pool water line and a matching 12″ x 12″ for the wall. The tile was complemented with 24″ bull-nosed travertine coping. Travertine was also used to create a new extended spillway.
Surface Preparation
The existing brick face was left in place, but was coated in mortar. In doing so we were creating a new tile beam, which is usually necessary in renovation work, but particularly in this case. Over this rough brick we needed a smooth and level surface for installation of the tile.
Centering the Tile
Our 12″ tile was centered on the wall between the water line and the spa spillway. The initial tiles set are the most important, as they establish the pattern for the entire wall. We chose to lay the wall tile on diagonals. This would create a simple but interesting pattern, which would contrast nicely with the lines of the pool.
Pattern Continued around Pool
The actual setting of these wall tiles was time consuming, requiring a number of cuts in the tile, particularly where the wall angled in and out from the pool. After the tile was set a topaz colored grout was applied. This color matched perfectly with the tile making the grout lines all but invisible.
Wall Tile and Spillway
Eventually the wall was completed along with the coping and water line tile. The effect new tile, particularly against the against the color of the water was visually stunning!
