Foam & cement:A look at construction

Published on Thu, Mar 3, 2005 by Jack Kintner

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Foam & cement: A look at construction

By Jack Kintner

Don and Debbie Scherck are building a new 3,500 square foot house on Allan Street out of styrofoam and concrete using insulated concrete forms (ICF) made in this instance by Logix. General contractor is Mark McGary of Square and Level construction of Bellingham who has 10 years’ experience building with this method.

The Northern Light’s series on house construction runs for the next four issues and will update the progress McGary makes as the house takes shape, in addition to covering other topics.

These will include a look at an extensive remodel/restoration of an older home near downtown Blaine now owned by Tom and Pat Long and a cosmetic renovation of the main floor of John and Dolores Bennitt’s house at Semiahmoo.

Long’s house was built 102 years ago by a sea captain who made extensive use of birds eye maple woodwork, all of which is in its original condition and has never been painted. The remodeling will focus on the kitchen area, a truly old-fashioned layout in which the sink is in a large but narrow pantry off the main 11.5 x 12.5 foot main kitchen, probably to be near the freshwater pump that was once connected to a well beneath the house.

The main kitchen, despite its small size, also has five doors, two windows and a china cabinet made of old-growth fir that is embedded in the wall between the kitchen and the expansive dining room.

The Bennitt’s house near the first hole fairway on the Semiahmoo golf course is a compact and fairly new two-story retirement home that doesn’t at first seem to be a likely candidate for what’s essentially a main floor face-lift. But once completed, the place seems transformed by the Bennitt’s project primarily because of the skill of their contractor with both paint and woodwork.

That’s all for future issues, though, so for now it’s back to the Scherck’s new house. McGary is sold on this construction method because it provides for quick building time and provides a very secure, quiet, well-insulated house that’s impervious to insects such as termites and carpenter ants.

When McGary began putting together the exterior walls once the lot was excavated by Bob Cazabon, it looked as if he’d somehow opened a box of giant Lego’s. Each module is four feet long, a foot and a half high and over a foot in width, counting the eight-inch space between the styrofoam sides, each of which are two and three-quarters inch thick.

“That thickness in the styrofoam lets you mount a regular electrical box without having to rout out a hole,” said Scherck, “plus making for a bit sturdier construction.”

The blocks are stacked on top of each other and taped and glued when necessary. “It is important,” said job foreman Tim Hayes, “to be a little careful with the material. It breaks more easily than wood when it’s being put together.”

Walls go up about 30 percent more quickly than with a regular concrete wall put together with plywood panels and snap ties. “The drywall screws to the inside surface once the concrete’s poured and the exterior siding screws to the outside,” Hayes said, “and you never have a snap tie let loose.”

Once finished, the ICF method provides an insulation value of R50, almost three times that of a conventional wooden wall’s R19. It’s got a three-hour fire rating as opposed to 15 minutes for a wood framed wall, and provides a superior vapor barrier that doesn’t require air spaces, so you get better insulation without the sweating and trapped interior moisture common in wood frame walls, which no matter how well built always seem to leak somewhere.

Inside a wood framed house one usually hangs heavy objects like kitchen cabinets and appliances by screwing them to studs set 16 inches apart inside the wall. A wood screw in a wooden stud will securely hold about 100 pounds, Hayes pointed out, and in an ICF system mounting screws go into an embedded plastic backing about two inches wide set on eight inch centers. “They won’t be quite as secure,” he said, “so we use more of them. But basically you can put things pretty much where you want to.”

Part of Scherck’s ICF walls will be below grade, and for that McGary will protect the exterior styrofoam with an impermeable barrier, essentially a rubber sheet, because styrofoam in contact with the ground must be waterproofed. That’s still an improvement over wood, as some builders feel that sooner or later any wood in contact with the soil will decay.