Considering design

Most ICFs come in the same size as actual concrete blocks — 16 inches long and 8 inches high. You can benefit from these standardized sizes by designing the size of your floor plan to be some measure of 16 inches. By designing to this module, you’ll reduce the need for cutting and speed up construction.

ICF homes can be designed in any style and will accept any traditional exterior finish including wood siding, stucco, board siding, shingles, and brick. (Find more on siding)

Their small, modular size makes ICFs a great option for creating curving or angled walls. With a handheld rasp, you can sand and round out the edges of the forms to create a softer appearance.

The strength of the concrete gives you the ability to create large openings as well. Just as you would with LEGO blocks, make the openings fit within the spacing of the blocks, rather than just randomly punching holes for your windows and doors. As with any building, window and door openings are made slightly bigger than the window or door you want to put into the wall.

Simple wood pieces (called blocking) can be used to fill in the extra space around the windows and doors.

Remember: Most ICFs come in standard sizes of 4-inch, 6-inch, 8-inch, and 10-inch widths. The insulation is on the outside, so although a thicker wall will be stronger, it will not give you any added insulation value. As a minimum, use at least a 6-inch-thick wall form.

Convincing Your Contractor

Although it looks new and different, anyone with construction experience can quickly get up to speed on ICFs. It’s more important that your contractor have concrete experience than direct experience working with ICFs. One person with ICF experience can easily train the rest of the crew. (For information on working with ICFs, contact the Insulating Concrete Form Association at 888-864-4232 or go to http://www.forms.org)

When the crew has some practice, each ICF home requires less skilled labor and less total labor than a wood-frame home. Plus, ICFs are very lightweight, so crews stay fresh through the day.

If your contractor still isn’t convinced, show him how easily chases are cut into ICFs with a knife, even after pouring the concrete. Fastening drywall or siding is simple; you do it with screws instead of nails.

When your contractor tries ICFs, he’ll soon see their benefit and want to continue building with them. If he’s new to ICFs, you may want to share the following tips with him: