If you choose to use wooden bucks for the doors and windows of your ICF project, keep the following in mind:
There are three main methods of constructing wood bucks: 1. External- The buck is the same width as the insulating concrete form; 2. Internal- Inset or recess the buck into the cavity of the form; and 3. Combination- Use plywood in combination with dimensioned lumber.
Regardless of the wood buck method you use, the buck must be anchored to the concrete wall using nails, screws or anchors. Pre-building the bucks to the rough opening dimensions off-site will increase on-site productivity. Also, a slot in the bottom or sill of the buck must be built to allow for proper placement and consolidation of the concrete below the opening.
Use pressure-treated lumber for the bucks and sill plates. ACQ lumber will corrode ordinary galvanized fasteners, so be sure that you are using the properly coated fastener. If you must use regular lumber for bucks or sill plates, a moisture resistant barrier must be placed between the buck and the concrete in accordance with the 2003 International Residential Code (IRC), Section R319.1.
The buck must be braced every 2' both horizontally and vertically to resist concrete pressures from bowing the buck. The buck must also be kept square by bracing the corners or running a diagonal across the buck.
Village Plaza is the largest ICF project in Minnesota history. The four level, mixed-use building, located just north of Minneapolis in Circle Pines, Minn., proves that ICFs are perfectly suited for large commercial jobs.
Advantages include an accelerated construction schedule, the ability to continue work in harsh winter weather, energy savings, and more.
The $25 million, 112,000 sq. ft. complex will will be completed in just a few short months. Groundbreaking ceremonies were held in October 2004. ICFs allowed construction to continue through the Minnesota winter—the only protection needed after the pour was at the top of the wall, and the energy-efficient walls significantly reduced the cost of temporary construction heat.
“One outstanding aspect of this project is the 64-foot clear span concrete beams,” says Ed Scherrer, a nationally recognized ICF technical expert and owner of PolySteel of Minneapolis/St. Paul. The hollow-core planks are used on all the building’s four floors.
PCI, the ICF contractor, used Polysteel’s standard 24-inch-high blocks to make the big walls come together fast. A 4-inch “height adjustor form” kept waste to 5%.
Because of the height of the building, and the weight of the pre-cast trusses, most of the openings needed a lot of steel above windows and doors. Polysteel’s steel ties held the weight without any problems
The project has been an enormous success by all accounts. PCI is already looking for other large-scale commercial projects they can bid.
With the promise of energy-efficient, durable housing, insulating concrete forms (ICFs) are transforming the way America builds. ICF developments are springing up in the sands of the Southwest, and last year’s hurricanes have residents in the Southeast clamoring for the safety of ICF housing. But ICFs are experiencing unprecedented growth in the far north as well.
One major incentive—even in Alaska—is the rising cost of energy. Convenience is another draw. “To have a system that will insulate that crawlspace without having to go underneath the house after the fact is a major advantage,” says Steve Tallman.
Commercial contractors are doing a sizable business as well. Tallman sold all the blocks used in a 130-unit condominium complex built in Anchorage recently, and other similar projects are going up around the state.
Construction in Alaska can be unique. When the temperature plunges to 20 below zero for weeks at a time or the jobsite lies 200 miles from the nearest road, construction can be difficult, to say the least.
“ICFs are just easier to work with,” says Phil Summers, a Fairbanks ICF distributor. “There’s the cost savings, but there’s also cold weather protection. As long as it’s not too cold to batch, all we need to do is cover the tops, and the concrete will stay warm enough just with the heat generated through hydration.”
Builders, designers, homeowners and businesses in Alaska are discovering ICFs are a perfect solution for a difficult environment. It offers energy efficiency and seismic strength in a system that is simple to learn. It provides elegant solutions to challenging logistical and environmental hurdles while saving both the builder and the owner time and money.
Homes constructed with Insulated Concrete Forms are healthier, stronger, safer, more energy efficient and environmentally responsible. Who wouldn’t want a better home that’s also less expensive to own?
But where do you start?
Some homebuyers start by selecting a builder. That’s a good idea, since ICF builders will have developed a network of subcontractors (i.e., plumbers and electricians) who have experience working with ICFs.
More often, we see homebuyers starting the process by looking at home plans. Basically, two choices exist—working with a design professional to create your own unique home design, or, starting with an existing home plan. Either way, just about any design which can be built conventionally can be built with ICFs.
You will enjoy maximum flexibility if you start with a blank sheet of paper. You will need to know which ICF product you intend to build with, as wall thickness vary by brand. Our firm, Design Basics, charges $2.50 per finished square foot to design a brand new ICF home plan, so plans for a 2,500 square foot home would cost $6,250. The process would likely take six to eight weeks.
A less expensive and faster approach is to start with an existing home plan. Our company charges $845 for a 2,500 square foot homeplan, and $1,500 to adapt it for ICF construction. The changes typically take two weeks.
Most home plans can be successfully adapted for ICF building. When looking through existing home plans, fewer jogs in the foundation will simplify construction and hold the price of the home down. If you will be building a two-story home, designs which have the second floor stacking directly above the main level are best. If a plan includes second floor cantilevers over the main floor, we suggest eliminating the cantilevers by kicking out the foundation and main floor so the walls can be stacked.
With bedrooms over the garage gaining in popularity, you may need to add (or reposition) a steel beam to carry the load of the ICF wall. Also, while you can build bay and bow window areas with ICFs, sometimes these small areas would have so little concrete that it just doesn’t make sense.
The least expensive way to obtain ICF home plans is to select a design offered by the ICF manufacturer. Leading ICF companies have teamed up with top home design firms to make some of their most popular designs available in ICF versions. If one of these designs is to your liking, you’ll probably spend less than $1,000 and may be able to have the home plans tomorrow!
Once built, ICF homes are indistinguishable on the outside from their conventionally-built counterparts. But their beauty goes deeper—with lower utility bills, favorable mortgages, higher appraisals and increased comfort, peace and quiet. Why would you want to build.