I’m looking at both of these products for my new house. The ICF’s seem like they would provide the ultimate envelope but are far removed from what I think of as normal construction, IE: window depth, hanging cabinets, electrical routing, trim, venting, ANY wall penetrations, etc. The spray in foam seems like it could be a close second (insulation quality) with all basicly standard construction practices. I’m looking for other opinions out there!
Thanks for your thoughts!
Rich L.
Eastern Iowa
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Replies
I don't have much for you but I look forward to hearing from others who have experience with ICFs because I am interested in that too. My understanding is that you can cut channels in the foam to make runs for wiring, junction boxes and plumbing. I've heard that a heated wire "knife" is available for making quick clean cuts. As far as hanging cabinets and trim, like baseboard and window casing, I've heard that some builders make cutouts in the drywall and use polyurethane glue to attach ply wood nailing strips to the foam, also anchoring the nailing strips with screws long enough to screw into the concrete.
There are a thousand hacking at the branches of evil to one who is striking at the root. -- Henry David Thoreau
I guess the question is what are you looking for - just insulation/air infiltration issues. or something more. Price the spray foam...I had estimates in the 7K range for my roof deck, and the house is only 1700 s.f.
I just built an ICF house this summer - it went up very fast, and is extremely strong, well insulated, basically bug and rodent proof, has wide windowsills, thermal mass, there is a peace of mind factor during storms and it is quiet (I live near a railroad). These are some of the reasons I built it with ICFs.
window depth, hanging cabinets, electrical routing, trim, venting, ANY wall penetrations, etc.
I was concerned about this type of thing too, since I knew only standard construction. None of these were even close to a problem. The solutions were (in order)
Extension jambs - do you have a tablesaw? - these were no sweat.
We used Amvic forms - the webs held the wall cabinets fine, we used a lot of screws, and screwed the tops to a soffit as well, so no probs. Sheet metal or let in plywood are other solutions.
I bought a $29 electric chainsaw and cut all my wire runs in an hour.
The webs hold trim nails OK, but I used a few trim head screws. There isn't that much trim on exterior walls when you think of it, and window and door openings have framing lumber for nailing.
HRV if you want, we're waiting to see if we'll need one many say they don't.
I forgot to sleeve on hole and rented a 2" drill ~$50 with the big bit. 10 minutes later there was a 2" hole through my 8" 4500 psi concrete wall. No sweat. I ran wires over the top plates and down grooves to exterior lights and outlets.
I have no spray foam experience, but I can say I would do the ICF thing again - it was an enjoyable way to build.
Thanks for the replies!
Do you think it's worth doing just the basement in the ICF's? The East wall is going to be a walkout. Unfortunately I didn't start my research soon enough in the design process and I'm being told that my upper floor plans may not work well for ICF's. There's a bump out window seat, bay area in the dining room, and a cantilevered corner that don't sit directly on the basement walls. Could I do most of the upper level in ICF's and just do these spots traditional wood frame with spray foam?
Thanks again for all of your input! The more I read about ICF's the more intrigued I am. Unfortunately I preparing to dig my hole as soon as the weather straightens out and that's getting awfully late in the game to make these kind of changes!
Best regards, Rich
There's a bump out window seat, bay area in the dining room, and a cantilevered corner that don't sit directly on the basement walls. Could I do most of the upper level in ICF's and just do these spots traditional wood frame with spray foam?
What do you mean by a bay area? Does this have a foundation under it?
Yes - ICFs are really straightforward, and these you wuold treat like window openings etc. If you want to keep the insulation package consistent, maybe SIPs for those areas.
There are internet forums for ICFs and a HUD manual called "Prescriptive Manual for ICF Construction" Google these and you will know a lot.
Treat every person you meet like you will know them the rest of your life - you just might!
Thanks for your reply Brian.
"What do you mean by a bay area? Does this have a foundation under it?"
I may not be using the right terminology here. I'm not a builder, I'm an HVAC guy and I really appreciate everyone's help! The bay area I'm trying to describe is in the dining room, the walls go out at an angle, windows both sides, then a large picture window in the middle. It sits about 1-1/2 ft. out from the straight back wall of the house. There is a foundation under this area but it's a straight wall and this area sticks out over it. Window seat area is similar with straight walls going out, same foundation as "bay area". Hope you can get what I'm trying to describe by my explanation!
Thanks, Rich L.
While I'm most familiar with ICFs, having built a number of those, anything with decent insulation is the way to go. SIPS look real good as does the double 2x4 walls.
My carp buddy who helps put up ARXX ICFs is using it for both the basement and first floor of his addition since once you are set up with the ARXX bracing for the basement, the next floor goes up even easier since it's just stacked on top of the basement walls. The floor is attached with simple ledger clips that are held by the concrete in the walls.
Check out the ARXX installation manual and other information available at http://www.arxxbuild.com/ Most of your questions can be answered on the site since the documentation is very well done.
For costs, we just installed 66' of 8' wall with block cost of about $2500, including a weeks rental on the ARXX bracing system, verticle wire clips, large nylon ties. The 8" block took about 19 yards for the wall and footer. We went through about 75 sticks of #4 bar, with 12" verticles as required by IRC. If the ARXX design requirements can be follow instead of IRC the verticles could have been on 24" centers, saving 15 sticks or so.
You'll also want a $40 foam gun and some foam (3 28oz. cans for our project), ARXX block lock (a zig zag wire reinforcment used every other course of block), a tie wire reel and a few rools of tie wire.
For basement waterproofing, Grace Ice & Water works great and is easy to put on. We used 2-1/4 rolls when applied 6' and overlapping the edge of the footer. A 2x4 along the top edge will keep the Ice & water from peeling away from the block until it's backfilled and keeps the top edge clean until the exterior finish is applied above ground.
The window and door openings are probably best lined with pt 2x as described in the installation manual. The PVC window bucks work, but they don't allow the flexibility of the wood bucks.
It's a good idea to have some OSB ripped 8"x16" to reinforce block cuts, broken block and other areas that need a little help. We used 3 sheets just for these.
The fiberglass tape is used to hold blocks down and avoid verticle separations and it's quick insurance for most pours and absolutely necessary if you use block heigth extenders.
If you use an ICF system make sure you have read the installation manual and have a backup means of straightening the walls after the pour since they won't be perfectly straight. Most of the waves can be taken out with the ARXX bracing, if installed well and the walls are leaning in slightly. The bracing can push, but can't pull. Our backup system is usually just 2x6s placed opposite the bracing and pushed on with spring boards, or extra ARXX braces, to get everything to match a stringline.
The bracing accepts a scafold plank holder so it's easier to install the top rows of block and to finish the rebar placment and pour. LVLs work the best so if there are any on the rest of your house simply order them early. Some ARXX suppliers may have some extra planks to lend.
Converting stick framed wall plans to ARXX is pretty easy so you might want to consider it even if building is not far off. The walls are thicker so you'll need to adjust some things. The main advantage is that after the shell is poured all the exterior framing (other than roof) and insulation is done. Truss clips can be molded into the upper walls so trusses are set as soon as the contrete has hardend up a bit.
A spray foam house can be quite nice, but the two main downside issues are lack of thermal mass and sound deadening.
A concrete wall is quiet, quiet, quiet. Add 4" of foam (the ICF) and it's even more quiet.
The thermal mass in the wall helps to even out the high and low temps so the insulation can work better than if the concrete wasn't there. ARXX says they have research that shows the effective (real world) R value of an ICF wall to be between R-40 and R-50 depending on your climate.
We just finished stripping forms on an ARXX 330 sqft basement addition.
SIPS try the search. Lots of info.
ICF's, good too, lots of info lots of bad info too. (R-50 with 4" of bead board?)
I was even told that the concrete under compression from the snow load produced heat. These guy's will repeat anything to sell you there product. Effective are values compared to what?
Do your research.
Garett
I think you're looking at it backwards. These are
different types of structures, first and foremost.
They happen to share in common something called "foam."
Masonry vs sticks. Which one would you want to be
in when the wolf is at the door?