Some builders diving into ICF pools
Insulating concrete forms are making waves in pool construction, but are they right for your project?
Many DIY homeowners and pool professionals alike are hailing ICFs as being an easier, faster and more energy-efficient type of pool construction. ICF pools use hollow foam blocks made with expanded polystyrene foam and plastic bridges, or webbing, to hold the block sides together. These blocks are stacked and locked together to form the perimeter of the pool. The block wall is then filled with rebar-reinforced concrete.
ICF technology has been used for decades, most often in home construction. The foam provides greater insulation and a sound barrier, while steel-reinforced concrete makes the walls more resistant to disasters, like fire or high-impact winds, than traditional wood structures. The technique is still new to the pool industry but is gaining momentum.
Proponents say ICF pools can not only be built at record speeds but also with less of a skilled labor force than traditional pool construction.
“I always ask anybody who calls me if they’ve ever played with Legos before,” says John Bluemlein, ICF pool sales manager for BuildBlock Building Systems. “If they say, ‘Yeah,’ I say, ‘Well, you’ve already mastered setting up the blocks.’ ”
BuildBlock manufactures ICF blocks for all types of construction. Bluemlein and Dustin Cox, BuildBlock sales director, say their company sells to many homeowners who build their own ICF pools.
Because construction is simpler than traditional methods, it also allows contractors to complete a pool with fewer workers or machinery and in less time. Steve Mercer, owner and CEO of PrestonGreen, LLC, says his company can build an ICF pool in as little as 14 days.
After excavation for an ICF pool, braces are installed to hold the blocks in place. Because the blocks are lightweight, they are easy to maneuver and place in the desired pool perimeter. ICF block manufacturers can even create large panels for the walls by attaching the block forms together before arriving on site. This means progress is less contingent on weather or other factors.
According to Mercer, this is only possible by using Helix Micro Rebar in lieu of traditional horizontal rebar. Helix Micro Rebar are small pieces of screw-shaped steel that are mixed with concrete before being poured. Helix Steel states this kind of rebar is stronger, more durable and more flexible than traditional rebar.
Paolo Benedetti, CEO of Aquatic Technology Pool & Spa and a licensed general contractor, is more cautious about using ICF blocks to build pools. Based on his experience with ICF buildings, he warns about the risk of potential leak points.
Most ICF pool builders pour the concrete floor first and then build the walls after the floor is set. The corners where the floor meets the walls or the walls come together could be cold joints that allow leaks from within or outside the pool, Benedetti says.
Cox isn’t concerned about leaks because the liner, plaster or other finishing material inside the pool should waterproof the inside; water stop strips can also be applied on the outside of the pool where necessary, he says.
Mercer’s method of addressing the leakage concern is to use a Basecrete bondcoat to waterproof the cold joints and round out the corners. He also applies it to the tile line to hold decorative tiles in place.
Another solution Mercer recommends is using a mono-pour method. He cuts the bottom of the inner foam pieces, and as the concrete is poured, it naturally flows under those cut pieces, allowing the footing and the walls to be combined in one continuous pour.
However, Benedetti also notes there is no way to visually check the structural integrity of the concrete because the foam remains in place.
“Every one of those seams is a potential leak spot for water to migrate into the concrete that’s inside the block,” Benedetti says. “Now, if you have a void or some type of defect of the concrete inside a honeycomb — an air pocket or something — you now have given water a place to get into the inside of the wall.”
However, Cox notes that mono-poured ICF pools are structurally similar to other forms of pool construction, such as gunite or shotcrete. “If water infiltration is a concern, it is a good idea to utilize a waterproofing membrane and drainage tile to alleviate hydrostatic pressure, especially if the pool will be drained,” he says.
Because ICFs are still new to the industry, companies are testing and creating new finished products. Liners are a possibility as well as any type of traditional plaster, Cox says. Bluemlein recommends Sider-Crete, a type of roll-on plaster.
Rather than plaster or liners, Mercer coats the interior of all his pools with polyurea, which is a product commonly used as a truck bed liner. He prefers polyurea for a pool finish because it is durable and resistant to chemicals, pH changes and UV light, he says. He mixes it with 80-mesh sand to change the color as desired.
However, Benedetti cautions that plastered ICF pools will be difficult to remodel or repair down the road. Because the plaster is applied directly to the foam, removing it will likely tear apart the foam. A repair process may be simpler with Sider-Crete, Bluemlein says. One could simply waterproof the damaged area and roll on a new coat of plaster.
When it comes to unique shapes, building above or below grade or adding additional features, like sun decks or benches, the sky’s the limit, Bluemlein adds.
“Anything you can do with a traditional concrete pool, you can do with an ICF pool,” he says. “It’s very simple to take a simple order of blocks and create anything you want for your backyard escape.”