We have our plan picked out and bid for ICF but the cost is going to be too high so ICF has to go along with finishing the upstairs bonus room and the 3rd garage.
 Specs:
 DFW TX area
2800sqft lower
675sqft upper bonus room
French country plan with steep roof pitches
Not a whole lot of windows.

I was thinking of just 2x6 24"oc with spray foam but after reading awhile that might be a waste of money. I was wanting the fully encapsulated attic so framing the bonus room and adding a mini split later would be an easy thing to do.  We also like lots of recessed can lights.  What stick building and insulation should I be looking at? What attic insulation? The a/c unit and duct work will be in the attic.

If you can't swing the ICF, you should find a contractor who can do Advanced Framing for you. With Advanced Framing, you could still get a more efficient shell.

What is the exterior of your home?

If it was me and the exterior was brick, I would go with 2x6 walls @ 2' on-center fully wrapped with 7/16 OSB for strength, then 1" of foil faced polyiso foam board insulation over that (joints staggered from OSB joints) with all foam board joints taped and sealed. Then have wet spray applied cellulose blown into the stud cavities. Allow plenty of time for the cellulose to dry before applying drywall. Don't use any vapor barriers on the interior side of the wall. That will give you R20 or better whole wall insulation value at a reasonable cost. Minimize west facing windows or provide awnings or covers to limit summer heat gain.

If at all possible, I would try to at least locate the HVAC unit inside the condition space. Surely you can find a 3'x3' spot somewhere inside the home to install a vertical air handler? If not, suggest framing out a small area in the attic just for the air handler and insulating around that. It will be much less expensive doing that with blown cellulose in the attic than spray foaming the underside of the roof deck, especially considering you have steep roof pitches which means lots of sq ft of roof deck to spray foam. You could easily have twice as much square footage of roof deck as you have in floor/attic space and spray foam easily costs 5 times as much as cellulose per square foot for a given R value and with the large roof deck you may be looking at ~10 times as much cost compared to cellulose. You can get most of the benefits of the spray foam at a fraction of the cost by having them spray the top side of the ceiling board with only ~1" of closed cell foam (at ~$1/sq ft) for air sealing and then blow in ~R38 of loose cellulose on top of that (at ~$1/sq ft).

Duct work, if installed in an unconditioned attic, should be well sealed with a minimum or R6 reflective insulation over the ducts. If you using rigid metal duct work, which I recommend, you might consider having the spray foam applied to the metal duct work at the time the ceiling is sprayed. I have seen that approach used several times in my area. Helps to insure no leaks in the duct work. Also dampens sound.

Since you are in an area that experiences frequent severe thunderstorms and tornadoes, I would also insure that you have a safe room built into one of your lower rooms such as a large walk-in closet over a concrete slab so that it can be properly anchored. FEMA has plans on-line for safe-room designs. One plan that is relatively easily incorporated into a new home uses wood stud walls (double 2x4 at 19.2" on-center) with heavy plywood over the studs and block in-fill for missile protection. Also insure your roof rafters/trusses are securely attached to the walls with metal strapping or hurricane ties.

I think that 2x6 plus cellulose and rigid foam is hard to beat. Not so clear on taped XPS vs EPS + building wrap. I do not like the idea of non-vapor permeable foil or plastic covered foam.

I have heard it suggested that anything such as ducts that will be sprayed with closed cell polyurethane that might need to be accessed in the future should first be wrapped with 6 mil vinyl so the spray foam can be peeled off without all of the scraping.  But how often are repairs or additions done on ducts?  I can not see how vinyl over metal ducts would hurt anything.  It should not take too long to do and vinyl sheeting is inexpensive in rolls.  Rolls are available in different widths and thickness.

It's going to be brick and Austin stone exterior. I have thought of just removing the staircase and putting the hvac unit there and run the ducts in chaises inside the house. Whats the best way to seal over the 40+ can lights? Bummer is the ICF included a FEMA 320 storm room.

Posted By fordracing19 on 02 Jan 2012 01:40 AM
We have our plan picked out and bid for ICF but the cost is going to be too high so ICF has to go along with finishing the upstairs bonus room and the 3rd garage.
 Specs:
 DFW TX area
2800sqft lower
675sqft upper bonus room
French country plan with steep roof pitches
Not a whole lot of windows.

I was thinking of just 2x6 24"oc with spray foam but after reading awhile that might be a waste of money. I was wanting the fully encapsulated attic so framing the bonus room and adding a mini split later would be an easy thing to do.  We also like lots of recessed can lights.  What stick building and insulation should I be looking at? What attic insulation? The a/c unit and duct work will be in the attic.

How high was the ICF bid? I doubt it was it the typical 5% that is espoused and more like the realistic 15%.+ You would figure that ICF contractors would be more competitive in this economy to compete with wood frame. But apparently not. From what I have heard and read, ICF guys are making their money right now in commercial.


Stay away from uninsulated recessed can lights. They are HORRIBLE when it comes to thermal loss. For every 20 canned lights in the attic ceiling roof, that is equivalent to having an open window up there. They do make INSULATED can lights, try those if you must have can lighting.

Posted By Lbear on 02 Jan 2012 01:05 PM

Posted By fordracing19 on 02 Jan 2012 01:40 AM
We have our plan picked out and bid for ICF but the cost is going to be too high so ICF has to go along with finishing the upstairs bonus room and the 3rd garage.
 Specs:
 DFW TX area
2800sqft lower
675sqft upper bonus room
French country plan with steep roof pitches
Not a whole lot of windows.

I was thinking of just 2x6 24"oc with spray foam but after reading awhile that might be a waste of money. I was wanting the fully encapsulated attic so framing the bonus room and adding a mini split later would be an easy thing to do.  We also like lots of recessed can lights.  What stick building and insulation should I be looking at? What attic insulation? The a/c unit and duct work will be in the attic.

How high was the ICF bid? I doubt it was it the typical 5% that is espoused and more like the realistic 15%.+ You would figure that ICF contractors would be more competitive in this economy to compete with wood frame. But apparently not. From what I have heard and read, ICF guys are making their money right now in commercial.


Stay away from uninsulated recessed can lights. They are HORRIBLE when it comes to thermal loss. For every 20 canned lights in the attic ceiling roof, that is equivalent to having an open window up there. They do make INSULATED can lights, try those if you must have can lighting.

Well the thing is the bids are apples to oranges. The ICF bid still has the 3rd car garage on it. Im thinking  8% over 2x6 and spray foam that the other builder quoted. What a hassle and we haven't broke ground yet. It gives me a headache. LOL

You only got one ICF bid?

Posted By fordracing19 on 02 Jan 2012 06:40 PM

Well the thing is the bids are apples to oranges. The ICF bid still has the 3rd car garage on it. Im thinking  8% over 2x6 and spray foam that the other builder quoted. What a hassle and we haven't broke ground yet. It gives me a headache. LOL

Why are you building instead of buying an already built home?

Building your own home can be a nightmare or a labor-of-love, depending on how you approach it and what type of contractor you have working for you.

A lot of contractors are not trust-worthy, IMO. Everyone needs to make money but some contractors take advantage of owners. For example, one ICF contractor who was also going to be the General Contractor, he sub-contracted the stucco and priced it at the SAME EXACT price that a wood-framed home stucco job cost. It would have slipped by the homeowner but he caught it. The homeowner called out the stucco guy himself and bid out how much it was to put 2" of EPS and stucco the home. He then asked the stucco guy if the home already had 2" of EPS on the home (hence what an ICF home already has), how much LESS the bid would be. The stucco guy said that not having to put the EPS on the home saves him LABOR & MATERIAL COST by $5,000. The ICF contractor was pocketing the $5,000 plus up-charging another 10% onto the bid for being the GC.

When the GC is calling out subs to do the work(electrical, plumbing, drywall, etc), the GC is making 10% on the each job they sub, which is part of the deal of being GC. Where some of them go bad is when they are ripping people off by lying on the bids. With an ICF home you already have 2.5" of EPS on the exterior. The stucco bid of an ICF home should be LOWER than that of the exact same type OSB wood framed home because the stucco guy doesn't need to put 2.5" of EPS on the home.

Posted By ICFHybrid on 02 Jan 2012 08:25 PM
You only got one ICF bid?

The problem is that some areas only have ONE or maybe TWO ICF installers. In the area I am in, there are only 4 ICF installers, 2 of them only dabble in it, so in reality you only have TWO experienced ICF installers.

Posted By ICFHybrid on 02 Jan 2012 08:25 PM
You only got one ICF bid?

Yes, just one bid. We looked at over 60 homes before deciding to buy 11 acres and build. We built our last house in 2004 and contracted it out ourselves. The wifes uncle was a local framer and knew all the other trades.

Go to the ICF forum on here and see if any of them are in your area. I think there is. You really need to get several quotes.

Basic layout of the house. 3rd car garage will be gone and study is increasing to 12x20 for a media room.

there are only 4 ICF installers, 2 of them only dabble in it, so in reality you only have TWO experienced ICF installers.

So, who wants to do it the most? There were only three possibilities in my area, too. Once you get the bids, you need to talk with them and ask "What can we do to get the price down any more?"

This is a beautiful house but I think there will be a lot of money tied up in the roof.  Be sure that the rafters/trusses are tied well to the walls.  A tall roof like this will have to withstand a lot of wind pressure.  Closed cell spray foam would also help glue the rafters/trusses to the roof decking.

You would have even more usable space under the roof if the roof was built without rafters/trusses.  You might want to consider some type of paneled roof such as SIPS or SCIPS.  I know of a SCIP company that covers the Southeast but I do not know if they will go as far as your location.

With a custom home, you have the perpetual problem of a one-time amateur (the owner) dealing with professionals who do it every day. The pros come out ahead. Plus now we have the problem of the market price being 30% less than the cost to build.

How will you structure the contract(s) with the GC or subs?

Alton is right- independent of wall construction type, the roof will be a big expense, and will be a large performance variable. The more dormers & valleys the greater the framing fraction, and the harder it is to air- seal, reducing the thermal performance of the roof, which appears to be the vast majority of the exterior surface area. Siting & orienting it for minimal solar gain at the roof can make a large difference in cooling-season performance. Panelized systems with low bridging, better air tightness, and thermal mass will make a real difference here. (Do they make ICF roofs? :-) )

Dana. What if I did the 1" cc foam then piled then piled the celluolse on top while moving the hvac into interior soffits and an equipment closet?