Technology offers endless design possibilities for packaged pool kits

by Sally Bouorm | October 1, 2013 9:27 am

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By Bill Wiley

For much of their history, steel swimming pool kits were manufactured like cookie cutters. Manufacturers would typically offer a few different shapes—square, rectangle, oval, or octagonal—in a couple of different sizes, with a handful of choices for steps. The homeowner simply picked one from a book and that was that. Without the advantage of today’s technology, each steel panel had to be cut and bent by hand as manufacturers simply did not have the staff to complete all of the labour-intensive customization.

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Today, it is a whole different world for steel pool manufacturers, thanks to two technological breakthroughs. The first was the advent of computer-aided design (CAD) software approximately 20 years ago. It allows design engineers to configure steel pools with custom panels and supports on a computer screen and instantly confirm whether the resulting design meets building specifications. This made it easy to provide homeowners with a steel pool in virtually any shape or size they could imagine.

The second, more recent, breakthrough was computer numerical control (CNC) manufacturing equipment. This technology, which solved the labour barrier in producing custom shaped and sized steel panels, was introduced to the pool industry about a decade ago. Now, manufacturing equipment can translate the CAD design to actual product by automatically punching out, cutting and bending steel panels to meet precise measurements.

Essentially, what this means is every steel pool is a custom job, with each panel fabricated exactly to design. The huge advantage for the dealer is they can offer their customer virtually endless design possibilities and options in a cost-effective manner. Multiple radiuses in any size, ornate steps, sun ledges, wading pools, radius steps, full length benches—anything that can be done in a gunite pool design is now available in a steel pool kit.

Steel installation advantages

Steel pool kits also offer several advantages in the installation process. First, steel panels are exceptionally rigid; therefore, the installer does not need to worry about keeping the pool walls straight and true, because the steel walls hold their shape. Further, as steel panels come in 2.4 m (8 ft) lengths, there are fewer seams, so they tend to be quicker to build.

While steel wall pools require less deck support than other pool types, it is still important to ensure sufficient bracing to support the concrete deck. Braces every 1.2 m (4 ft), including a brace at the centre of each 2.4-m (8-ft) panel are recommended. There is a higher chance for the deck to crack if supports are only used at the ends of the panels.

Improved durability

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There are several reasons why today’s steel pools will last longer as well. First, the quality of installation has generally improved as most installers are better trained and are using better building techniques.

Corrosion is another issue with respect to the steel’s durability. It becomes even more of an issue with saltwater-based pool systems. To overcome this, most installers are applying approximately 3.1 mm (0.124 in.) of wall foam to the steel panels prior to installing the vinyl liner. This protects the liner from any damage caused by steel corrosion.

Some manufacturers have implemented a number of additional design innovations to further ease installation and improve durability. One such innovation is additional support under the skimmer, so that it remains rigid during installation. In addition, skimmers now typically go through the pool wall, instead of behind it. This method seals off the steel panel from potential water damage. Steel braces are also being used for ladder and handrail sockets, which further improve support.

Another key improvement is a triple bend on the top of some steel panels. This enables the top of the panels to turn underneath for greater rigidity and reduction of potential deflection during installation. This is especially important with the increased use of cantilever decking and automatic covers, where walls have to be straight and true.

One manufacturer has even added a pool base finish line to their steel panels. Marked at 51 mm (2 in.) from the bottom of the panel, this shows the installer where the base should finish on the bottom of the pool. This finish line assists the installer and makes their job easier and more precise.

Installation basics

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The installation process for steel pool kits has not fundamentally changed over the years. However, it is important to understand that it is the installer’s responsibility to ensure all building codes, swimming pool regulations, and regional requirements are adhered to and only approved products and building materials are used, and the specific instructions from the manufacturer are always followed.

Installation is typically a six-day process, but can vary based on weather and local building code requirements. Of course, prior to beginning there are a number of preliminary considerations. All building codes must be acquired and all necessary utilities (e.g. water, electrical, sewer [drainage], and heater fuel [if applicable]) must be obtained. A proper site for the pool must also be identified. This means a site without obstructions that has proper orientation to sun, shade, and other structures, and most importantly, a proper grade for drainage.

Day one: Excavation

The first task is laying out the pool. To provide working space, all outer dimensions of the excavation should be made 609 mm (24 in.) larger than the actual pool size. The excavation is outlined by four re-rods, one at each corner. It is also important to square off the excavation layout.

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Next, choose the elevation for the top of the coping (i.e. the top surface of the pool). This must be 76 to 101 mm (3 to 4 in.) above the highest ground elevation to prevent drainage problems. Conspicuously mark the highest elevation as the reference point. Always check the excavation depth from the reference point.

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Given a steel-wall panel of 1067 mm (42 in.) and a coping height of approximately 51 mm (2 in.), the depth of the footing excavation will be 1118 mm (44 in.). This depth, measured from the top of the coping, will be maintained in the shallow end and on the 609-mm (24-in.) over dig around the pool perimeter. (The over dig can vary based on the size of the braces used with the pool.) Most excavators will work from the deep end to the shallow end in digging process. During the excavation, a transit should be used to ensure the proper depth is reached. The more level the shelf, the quicker and easier it will be to set the panels. Also be sure to leave the 609-mm over dig as a working ledge.[7]

After the first part of the excavation is finished, lay out the exact pool size on the shelf. Then, on one side and one end of the over dig, mark the top edge of the hopper (i.e. deep end) slopes with string and cut the earth with a shovel using the string as a guideline. The excavated depth of the hopper should be 51 to 101 mm (2 to 4 in.) deeper than the finish dimensions. After checking to make sure the hopper is square, dig the plumbing trench at a depth of at least 457 mm (18 in.), reaching from the over dig to the equipment pad. This will make it easier to run the plumbing lines later.

Day two: Steel wall panel assembly

On day two, determine the placement for the skimmer and inlet fittings first. It is best to place the skimmer near the centre of one of the pool’s longer sides, in the direction the wind blows in the yard, to aid pool water circulation.

When ready to assemble the steel wall panels, set them in the over dig, leaning them against the side of the excavation in the order shown in the pool drawings. Starting at any corner, assemble two corner panels. Then, when two straight-wall sections are joined, use the braces attached at the top and bottom holes of the panel flanges and tighten the top and bottom bolts while checking for proper alignment. When the panels are flush, install and tighten all remaining bolts.

Proceed with the next panel joint, alternating in each direction from the first corner, using the corner to help stabilize the entire wall assembly. When using a step section, follow individual manufacturer instructions.

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After all pool walls are assembled, make sure everything is perfectly square and parallel. Then, fit the pool to the deep end excavation as close as possible and use an alignment string, along the bottom length of the wall, to straighten the long wall first. Recheck the widths of the pool at the corners and then measure the assembly corner to corner. When the dimensions are equal, the pool is square. When the walls are straight, square, and parallel, drive re-bar into holes in the bottom flange of the steel wall panels along the perimeter to secure them. Also, drive triangular stakes through stake pocket holes in each brace, straightening the remaining walls along the way.

To ensure proper assembly, the pool must be levelled to the predetermined elevations. This can be accomplished by checking the level at each panel joint and each of the step’s four corners. Level with the transit, using shims under the pool walls as necessary. This is an extremely important stage of the installation; therefore, enough time should be devoted to this process to assure a perfectly level pool.

Once the pool is level and prior to pouring the bond beam, install the main drains. Check all codes to ensure compliance. Then, check the wall panels one final time for proper level and be sure to fill any voids to prevent concrete from running underneath the walls. When placing the concrete, do so gently as to avoid disturbing the straight wall or level. The concrete footing mixture should be poured around the entire pool panel perimeter at a depth of 152 to 203 mm (6 to 8 in.) and at the width of the over dig.

The next step is installing the coping. Corner sections should be installed first followed by the long lengths of coping. During this process, make sure the liner receptacle on the lower edge of the coping is flush with the top inside edge of the pool walls.

The next big job on day two is preparing the pool bottom. First, install the skimmer, then using the predetermined positions in the pool wall to receive the inlets, install the fittings so they are ready to receive the liner.

At this stage, the pool should be plumbed. There are a number of approved piping types and methods to perform this task; therefore, check the local building codes and builder preferences first. When all is said and done, it is highly recommended the plumbing lines be pressure tested prior to backfilling. Once the equipment has been plumbed, a certified electrical contractor can complete the connections for the pump and any lighting.

Finally, once the bond beam has been poured, following the manufacturer’s guidelines, layout the finished dimensions of the pool using pins and string. There should be a minimum of 51 mm (2 in.) between the finish grade strings and the excavation. Fill and pack low areas and voids with clean sand and trim out any roots or rocks. Then, string across the slope diagonally, from the deep end corner pins to the 51-mm vermiculite line on the bottom of the wall panels, making sure the lines are tight and not sagging. Once these lines are in place, the pool bottom can be trowelled.

DO-IT-YOURSELFERS SHOULD BE WARNED

The results can be tragic if a steel pool kit is installed improperly. While a do-it-yourselfer can buy a swimming pool over the Internet and hire someone to do the excavation, there are numerous factors that can be overlooked. For instance, the pool can be out of level; the excavation can be too deep or not deep enough; and, of course, water and drainage management is bound to be ignored. There have also been instances, for example, of insufficient concrete on the outside of the pool. Should this occur, water inside the pool will drain out and the ground pressure outside the pool will increase until the pool literally caves in. Those who are not aware of certain issues such as the disposal of excavated expansive soils are also often likely to use it as backfill, which can result in the movement of pool walls. Poor finishing of the pool base, wrinkles in the liner, and leaking plumbing lines can also make for a very unhappy pool experience if not done properly by a pool professional. Experienced pool installers receive extensive training on all of the potential issues regarding installation—from filtration and ground conditions to drainage and overall safety. This is why professionals are able to confidently provide warranties on their installations. A pool installed by a do-it-yourselfer will have no warranty on the work and an improper installation can void the manufacturer’s warranty should the installation affect the products themselves.

Day three: Forming the pool bottom

Finishing the bottom of the pool can progress from either the shallow or the deep end; however, it is important to keep in mind the crew must be able to exit and enter the pool without disturbing any finished areas.

To do this, pour the pool base mixture directly into the excavation. At this point, the installation crew should use flat shovels for final placement. The pool bottom should maintain a minimum thickness of 38 to 51 mm (1.5 to 2 in.) throughout. Sharp edges or pockets where dirt can collect should be avoided. As the deep end slopes are completed and the hopper bottom is trowelled, remove the strings and pins, and clean any debris.

Day four: Installing the pool liner

Prior to installing the vinyl liner, wipe down the pool walls and tape the wall joints to create an air seal. If the project calls for wall foam, it should be installed at this time. Then, once the pool bottom is firm enough to walk on (usually by day four) and cleaned of any debris or small stones, the liner should be placed in the shallow end and installed into the copping starting with the corners, making sure all liner markings are correct. Then, move onto the corners in the deep end. During the installation process, make sure the liner is kept inside the pool so it does not catch on anything. Once all corners are complete, continue installing the liner bead around the pool perimeter.

At this point, the liner is now vacuumed into place. To do this, a vacuum hose is taped between the liner and wall panel at the break-over (the point where the shallow end meets the start of the deep-end). If needed, a second vacuum hose can be configured in the same manner on the opposite side. Next, ensure all areas are sealed (e.g. panel joints, return fitting inlets, skimmer plumbing inlets, etc.) to prevent air leaks.

Prior to turning on the vacuum(s), crew members should position themselves behind the shallow end wall corners, in the over dig area, to grasp the liner near the seam at the bottom of the corners, pulling it upward and holding it in place to remove wrinkles.

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Then, holding the liner in the pulled position, turn on the vacuum(s). This will draw the liner into the shallow end until the deep end is fitted by the suction. This method also minimizes excessive stretching of the liner. Once there is sufficient suction to hold the liner from slipping, crew members can slowly release the liner and fit it into the corners in the shallow end.

Finally, once the liner is wrinkle-free and seated correctly, start filling the pool with water while the vacuum(s) are still running. After 152 to 203 mm (6 to 8 in.) of water has filled the deep end, turn the water off and install the main drain gasket and face plate while underwater. Then, continue filling the remainder of the pool. The vacuum(s) can be turned off and hoses removed when approximately 152 mm (6 in.) of water is in the shallow end. Then, install all skimmer and inlet face plates following the manufacturer’s instructions.

Day five: Forming the deck

On day five, pressure test the plumbing (if not done already). Then, start backfilling the over dig making sure not to push the pool walls inward. To help offset the pressure of the backfill, the water level in the swimming pool should be at least halfway up the vertical walls.

Clean sand, pea gravel, or small grade limestone are excellent materials for backfill; expansive soils should never be used. Excessive water soaking around the pool to settle the backfill should also be avoided. During this process, drainage of the pool deck and surrounding yard should also be considered. It is also a good idea to leave some excess fill for filling any voids should settling occur.

Next, form the deck using two-by-fours or masonite strips, keeping the same distance around the entire pool perimeter. Screed backfill inside the deck form to maintain a constant depth (between 89 and 101 mm [3.5 to 4 in.]). Finally, mount safety rope anchors and coping clips before pouring the deck.

Day six: Pouring the deck

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Concrete for the deck should be ordered a day or two in advance. The deck should not be poured on a day when rain or excessive heat is forecasted as these variables can ruin the concrete finish.

Should weather permit the deck to be poured, first mask off the top edge of the pool coping to protect it and then place the concrete into the forms and strike off the surface with a screed board. Then, proceed with the usual steps for concrete finishing.

Of course, no swimming pool installation is complete until safety guidelines have been met. Be sure the homeowner is aware of these. Guidelines include proper fencing around the pool, installation of safety rope, and required safety warning labels pertaining to pool use and diving.

 

 

 

Bill Wiley is the product manager for Latham International, a manufacturer of inground residential swimming pools and components in North America. He is a 43-year veteran of the swimming pool industry who started installing and servicing pools while in college and then became co-owner of a successful pool company in Albany, NY. Wiley joined Latham’s sales and marketing department in 1983, holding positions such as director of marketing, sales director, and director of customer and technical services. He can be reached via e-mail at billwiley@lathampool.com[11].

Source URL: https://www.poolspamarketing.com/trade/technology-offers-endless-design-possibilities-for-packaged-pool-kits/

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