Whether to Build with ICF or traditional framing?
I am in the planning stage for building a cottage. An existing cottage will be torn down and a new one built to replace it. The basement will be made using ICF (currently no basement or reliable foundation on existing cottage). The decision that I need to make is whether to continue with the ICF for the upper two floors to the roof or to build the upper two floors with traditional wood framing.
I have read lots of articles promoting ICF as a building material, but written mostly by the manufacturers. I would like to get some "real world" feedback from builders or home owners that live in (or build) foundation to roof ICF homes.
Taking labor into account the claim by the manufacturers is that building costs for ICF are only about 5% more expensive than traditional wood framing. Reading some of the feedback on this site some people claim 3x to 5x more expensive for ICF. I am still waiting for a quote on ICF installation so I don't know what to think about this difference in expense.
I am building a cottage in Zone 5 (Ontario). The cottage is adjacent to a lake with a lot of tree coverage. The exterior wood on the existing cottage (built in 1963) suffers from a lot of mold/mildew/moisture damage, so I would guess that the area is dark and damp.
On the plus side for ICF I like the idea of a quick installation (by a qualified professional). Given the choice I would like to have this structure built quickly.
The other thing that I really like is the solidness of the concrete walls. We have endless problems with small rodents tunneling through the 2x4 walls. They chew up the insulation and leave it in clumps for nests. In some cases the mice/chipmunks completely remove chunks of insulation. The insulating capabilities of my existing walls must be almost non-existent by this point in time.
Heating will be a combination of wood stove and forced air propane furnace. The area is isolated from any gas line service so propane will have to be trucked in and stored in tanks. I am restricted to using the EXACT same foot print as the existing cottage so there are some limitations as to what can be done regarding passive solar heating and my architect is addressing that.
The expected usage model will be continuous occupation during the Summer and Fall months and then only on weekends every two or three weeks during the Winter, so the cottage will remain empty for a stretch of 2 to 3 weeks at a time over the Winter. I expect to never completely close down the cottage. When we are not present I will maintain the furnace at 7 Celsius during the Winter just to ensure that the pipes don't freeze and the place doesn't become an ice-cube when we are away. At some point in time in the future I expect to live there year round.
For the moment lets assume that the differences in building costs are not significant and not address those yet. My 2 biggest concerns are;
1) What would be the relative difference in cost of heating the ICF during the Winter versus wood frame construction (ie 2x6 with Styrofoam sheathing outside or double stud 2x4 walls)
2) Given that the concrete has a high thermal mass, if we are away for 3 weeks (with temp left at 7 Celsius) how long would it take to warm the cottage back up to a comfortable level?
Keeping in mind that future rodent damage is almost a given. This may not happen immediately but it is sure to happen.
Whats the level of comfort living in a "concrete block"? Is it comfortable? Are you always cool and damp? Is it toasty warm?
What do you recommend and why? ICF or wood? Are there any ICF home owners out there that can comment. Was it a mistake? Do you like it? Was it the best thing you ever did?
Posted Oct 13, 2011 12:41 PM ET
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