AR15.Com Archives
 Tell me about ICF construction
HomeSlice  [Team Member]
3/17/2012 11:04:59 PM
I didn't want to hijack this thread, where several people recommended it.

The bit of reading I've done indicates that it adds 3-5% vs. traditional stick built construction, but is significantly more energy efficient re: HVAC, depending on what you read up to 30+%.

Has anyone here built a home using this stuff that would like to share your experience?

There appears to be multiple types of forms, so I'm curious about the pro/con's. Also, is it hard to get a contractor who can build it? Does the bank bitch because it's non-traditional construction?

Is a basement made out of ICF, or traditional poured concrete? Are there condensation problems? Does it drive up the electrical and plumbing installation costs?

Is it bullet-proof?

Thanks,
-Slice

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jim02  [Member]
3/17/2012 11:33:12 PM
I would like to know as well. I saw same thread but have not had time to research.
beakerello  [Team Member]
3/17/2012 11:36:00 PM
I haven't built with it.

Yes, you can build a basement with it.

When you are installing plumbing and electric you use a hot knife (has a wire that is heated) to carve out some of the styrofoam once the concrete is set.

Yes, there are all types of forms, my guess is that it is more personal preference than anything. I read about a product called Faswall the other day that is along the same lines of ICF's.

I think you are looking at more along the lines of 10-15% additional cost over conventional construction, from everything I have been told. Being told and having read are 2 different things.

I don't think you will have condensation problems if you seal it right and have good drainage.

When are you wanting to build? I have found lots of info, by going to the Home and Garden shows that are usually put on by the Home Builders Association in your AO usually in the spring. You will find lots of ICF vendors at these types of shows.

Hope this helps.

J
iNuhBaDNayburhood  [Team Member]
3/17/2012 11:43:03 PM
I've only done one project with ICF. It works well if you get the right contractor that wont skimp & cut corners reinforcing the framing of the forms during setup... problem is I've only ever met 3 contractors that do jobbs perfeectly as specified! all othhers would cut corners & cheat their own parents to make a higher profit margin. the engineer I work with often has done severeal, and agrees that if done right to specs they work well. Problem is most contractors dont do things according to plans & specs correctly. is it bulletproof? no. especially the honeycomb style forms! are there moisture issues? not if properly barriered & with proper backfill & draintile systems & sumps. electrical usually isnt too tough to install either, but it's easier with a preplanned electrical layout broke down by circuits. I wouldnt do it unless I found the RIGHT contractor with tons of experience framing & reinforcing things properly. otherwise hell no. better off doing a foundation in precast reinforced concrete. Sorry so disjointed. wrote this via cell.
gdawg  [Member]
3/18/2012 12:03:24 AM
We have built several basements out of it. They were all in the middle of the house so didn't have condensation problems. They were backfillled properly before we poured the cells. Normally we braced properly and had everything square before we poured the cells full. It is pretty interesting watching them tie the rebar into every block. We then used steel nailer plates to the top of the block,when the cement set up just a little, usually 2 foot on center. Then set the red iron truss system, with corrugated metal deck. We usually had a box-out for our electrical and HVAC, so we could get whatever we needed into the basement, without cutting concrete or metal decking.

Usually we had the box-out going into a 2 X 6 wall on the ground floor, or an angled wall so the ducting could go down into the basement a little better. The red iron trusses were 12-18 inch depending on the span, so plenty of room for lighting, ducting , etc. Yes it is a little more for the electrical, plumbing, concrete, etc but I feel it is a good system. The electricians use a tool the has a hot wire on it and it cuts right through the foam, for a track for the wiring. Couple of things we had problems with was drywall screws breaking off into the plastic bracing in the ICF block itself when installing drywall. And of course if you forgot to have something in the wall.

When you first see it being install it is flimsy and unstable. But after the rebar and concrete is installed it is really solid and steady. Maybe this helps a little if you can understand my construction lingo.

We have built a few homes out of it and it doesn't impress me doing the whole house out of it. Lots of things that just didn't seem right or normal like stick frame construction. Haven't heard much from the homeowners, after we built them, to see if it was that much more energy saving or not. The guy I am Superintendent for, I think took a class on it, but I don't think the bank has too much of a fit about it. They want to make money off of your construction loan, so the more money, etc,etc.
EXPY37  [Team Member]
3/18/2012 12:12:13 AM
Why not use classic rebar and forms that most any concrete contractor can do quickly and will turn out right if you SUPERVISE THEM and don't believe anything they tell you without verification.

HuckMeat  [Member]
3/18/2012 2:43:00 AM
Feel free to ask questions/PM, I built my own house and used ICF.

My cost was a wash because concrete was cheaper at the time and I did all the ICF and foundation work myself.
My ICF distributor had a 3 day class, and I helped out on a few pours so I'd know what to expect.

My parents built with the SIP panels. They are energy efficient and quiet too, but go up faster than ICF.

Yes, it helps SIGNIFICANTLY with your utilities. My utilities on this house are the same or less as my old house 1/4 of it's size.
I heat and cool a retardly large house for about $120 per month (less in the summer).

Bank doesn't care, to them it's like a commercial building - For other forms that are a little more edgy, like rastra, they cared a little.
I was my own GC, most GC's don't like them because they do take longer to get the whole building done. My plumber and electrician were fine with slightly modifying their methods.

I've shot an insert I had to cut out with .308. Bullet created a small pockmark in the concrete, but under the foam, so you almost couldn't tell from the outside that it had been shot. Nevertheless, bullets will eventually get through some kind of concrete, but it's of course, way better than plywood and 2x4.

I used a form called Nudura, do your research. There are some pretty crummy ones, some that are harder to install than others.

Biggest con is that you need to pre-plan every penetration (or pay the guy with the core drill later, as I had to do on a couple!) and it takes longer to get up.

Pro's - Super sound damping, I don't hear big winds until the windows start shaking. Super energy efficient, wonderfully quiet house, especially if coupled with radiant heat( which ties well to hot water solar).

Basement is done out of ICF too, waterproofed with platon membrane, and gently backfilled. Another (minor) con is that even though the foam is self extinguishing, building department is used to 1970's foam and made me sheetrock my unfinished basement. Not a big deal since I'll finish it soon anyway.

ETA: We poured 8" basement and 6" main floor walls, but it's an adobe style house, so the deeper walls actually helped with the effect we wanted. The nudura form doesn't have much to block the flow of concrete, and most concrete providers supply a special mix - Ours was a 4000psi mix with 3/8 aggregate and flowed right in. No blowouts in any pours.

Also, you don't get all that exterior door settling and sheetrock cracking like you do with stick frame often.
JosephTurrisi  [Member]
3/18/2012 9:26:06 AM
Originally Posted By EXPY37:
Why not use classic rebar and forms that most an concrete contractor can do quickly and will turn out right if you SUPERVISE THEM and don't believe anything they tell you without verification.



Because you will lose the insulating factor of the double sided foam. That being said I would not use the ICF method because I have wired two houses built using them. One was the basement only and the other was the whole house they were both a nightmere to wire and took alomst twice as long to rough end not to mention all the extra metal boxes and screws and anchors need to do them job which added more cost.
TaylorWSO  [Life Member]
3/18/2012 10:04:02 AM

Originally Posted By HuckMeat:


Yes, it helps SIGNIFICANTLY with your utilities. My utilities on this house are the same or less as my old house 1/4 of it's size.
I heat and cool a retardly large house for about $120 per month (less in the summer).



the ICF is not magical and that is not a fair comparison. The ICF provides a proper vapor barrier that gives a better savings but if you compared to the same stick built house with proper vapor barrier and traditional insulation you wont see the "significant" savings.
ilbob  [Member]
3/18/2012 10:26:09 AM
I hear from actual professional electricians about this pretty regularly. They claim it significantly increases their labor time unless there is a lot of solid up front preplanning that usually involves installing chases in various places. The consensus seems to be from them that it is somewhat more labor intensive. OTOH, many jurisdictions will allow the use of Romex in these type of constructions as it is VERY expensive to try and run conduit or EMT. I did hear the sad tale of one electrician who had to run EMT to meet local code and the self designed building had never planned for it. Very expensive labor wise.

But if you are doing the electrical work yourself, the labor is less of an issue.

I have heard estimates that suggest the construction costs are anywhere from 5-40% higher than for more conventional construction. There are reasons why there is such a huge variation. If you want it to look like a more conventional home, it costs more. If you go with the big open spaces that this type of construction encourages, the cost can be more reasonable.

The reality of energy savings is that if you run the number, whatever saving there may be in energy over the life of a mortgage is generally eaten up by a 5-10% increase in the upfront costs. Keep in mind that one must compare apples to apples. Modern stick built homes are far more energy efficient than those built in the past. There is nowhere near the difference in energy efficiency between a modern stick built home and one of these style homes as there is between an older home and any new one.
Surf  [Team Member]
3/18/2012 10:46:07 AM
Thinking of doing a garage/shop with ICF. That said money no object it would be covered in log siding to match the cabin. However it will end up with siding.

As mentioned above, like a log cabin, you need to pre-plan EVERY hole in it.

One of my co-workers built a hanger with ICF and loves it.














MP0117  [Member]
3/18/2012 11:07:20 AM




That looks really nice!


MP0117  [Member]
3/18/2012 11:08:31 AM
Have any of you guys heard of (or used) Superior Wall Systems?

http://www.superiorwalls.com/home
TaylorWSO  [Life Member]
3/18/2012 11:48:43 AM

Originally Posted By JosephTurrisi:
Originally Posted By EXPY37:
Why not use classic rebar and forms that most an concrete contractor can do quickly and will turn out right if you SUPERVISE THEM and don't believe anything they tell you without verification.



Because you will lose the insulating factor of the double sided foam. That being said I would not use the ICF method because I have wired two houses built using them. One was the basement only and the other was the whole house they were both a nightmere to wire and took alomst twice as long to rough end not to mention all the extra metal boxes and screws and anchors need to do them job which added more cost.
Thats why the concrete forms would be better IMO. 6" wall, poredtrditionally. 4" Ridgid foam on the outside. Steel studs on the inside. rest=traditional.

The steel studs take care of the wiring/pluming labor.

foam on outside= vapor barrier+insulation and the all important thermal mass on the INTERIOR.


I think the ICF are great except for the internal insulation. I want that thermal inside the structure to where I can use it for a heat sink to even everything out and keep the swings down.

Bonz23  [Member]
3/18/2012 2:17:00 PM
Take a look at Durisol or Faswall products. They are a cement-wood fiber based form that is like the foam forms but imho better. With the wood based forms you can nail or screw right to them, something you can't do with the foam. And the surface of the blocks is ready to go for plaster on the inside and either a stucco or brick/stone on the outside if you want to go that way to finish the walls.
fluwoebers  [Member]
3/19/2012 12:03:35 PM
Originally Posted By TaylorWSO:

Originally Posted By JosephTurrisi:
Originally Posted By EXPY37:
Why not use classic rebar and forms that most an concrete contractor can do quickly and will turn out right if you SUPERVISE THEM and don't believe anything they tell you without verification.



Because you will lose the insulating factor of the double sided foam. That being said I would not use the ICF method because I have wired two houses built using them. One was the basement only and the other was the whole house they were both a nightmere to wire and took alomst twice as long to rough end not to mention all the extra metal boxes and screws and anchors need to do them job which added more cost.
Thats why the concrete forms would be better IMO. 6" wall, poredtrditionally. 4" Ridgid foam on the outside. Steel studs on the inside. rest=traditional.

The steel studs take care of the wiring/pluming labor.

foam on outside= vapor barrier+insulation and the all important thermal mass on the INTERIOR.


I think the ICF are great except for the internal insulation. I want that thermal inside the structure to where I can use it for a heat sink to even everything out and keep the swings down.



this was my main turn-off with ICF also. Who wants internal insulation?
It looks like the Faswall and Durisol systems may solve that problem.
HomeSlice  [Team Member]
3/19/2012 12:37:20 PM
Can you help me understand the internal insulation thing? Most of what I've seen appears to be a 6" concrete wall with 2" of foam insulation on both sides of it.

T-WSO, you don't happen to have any pictures of one of those wiring jobs, do you?

ETA: I'm a little surprised by the reaction here. Generally this stuff is held in high regard in many BOL threads, but I get the feeling you guys who've worked w/ it before have a luke-warm perception... Interesting.


HuckMeat  [Member]
3/20/2012 1:09:09 AM
I'm trying to find my data, but I have temperature sensors embedded in most of my ICF walls - At the exterior, in the concrete, and underneath the sheetrock.

In Colorado's climate, we get fantastic temperature swings - 80 during the day, snow that night, etc.... What I find is that with the daytime/nighttime swings, the concrete core stayed pretty constant (say, a 3 degree swing) - Meaning all night, your heat system is working like it's a 60 degree day outside. The converse was true in the summer, where it would warm up a tiny bit during the day, and cool off at night.

While I like the super exterior insulation concrete idea, I did visit 2 homes built this way. My wife wouldn't live in a house like that, is about all I can say..
The first we visited in new mexico, and it was hot as shit (mid summer). I suspect over time, the energy infiltration across the outside foam still allowed the concrete to heat up, to the point that it's warm to the touch (The same way ice still melts in a cooler, just slower). Great during winter (except that it doesn't get warm to the touch in winter, just cold). The second was cold and damp. If you're going to go with an an exterior insulated concrete design, you'd better have a damn good building science engineer figure out your HVAC, dew points, and exchange rates. Here, in Colorado, (low humidity) Pouring vaults built into ICF homes has been popular. Typically, only the exterior side of these roofs was insulated, as they were generally used as wine cellars and wanted to be kept cool - Nevertheless, both of the concrete roofs without a thermal break poured this way had moisture issues during times of the year. My brother wants to build his house this way, in NM, but he doesn't have a wife who wants wall finishes, etc.

My first choice would have been real adobe, double walls, with a 6" insulation between them... I don't know if it's the nature of adobe, and all that baking in the sun, but exposed adobe is much nicer than exposed concrete. There is another ICF based on that thermal principle, but I don't think you can easily make up for double 18" thick walls with concrete.

If you really want the benefit of a thermal flywheel, you need to get energy into that concrete/mass through some means when you are heating, and keep it out when you are cooling. We did in floor radiant, tied to a propane modulating boiler. However, we sized the tubing runs and flows for lower temperature solar hot water, so the boiler can run less.

It's not perfect, but IMHO, much better than stick frame, and IMHO, better than SIPS (which I've helped build a house out of). Definitely do you homework, but I will never live in a stick frame house again.

I'd stay away from rastra, they have leaking problems like crazy. I'd looked at reward, polysteel, nudura, and a couple others. I like how quiet it is - When you walk into an ICF house, you'll know.

My floors and roofing are more traditional, TJI joists for floors, engineered trusses for the roof, entire underside of roof deck sprayed with spray foam sealed to the ICF's..... The more recent IRC energy codes have adopted conditioned attic space as an option when done properly as it A) reduces a lot of penetrations in the roof B) is more energy efficient.

One other caution - In a super insulated house, make sure your HVAC guys know their business... A) they won't oversize the equipment B) they won't rely on guestimates and crap to figure out make up air C) You'll need to budget extra for an HRV or ERV (About a grand) in an ICF or SIP house - Otherwise you won't get the air exchange that even the 'best' stick frame houses have (stick frame gets it through leakage), and when your dog farts, you'll still smell it days later.

iNuhBaDNayburhood  [Team Member]
3/20/2012 12:44:42 PM

Originally Posted By HuckMeat:
I'm trying to find my data, but I have temperature sensors embedded in most of my ICF walls - At the exterior, in the concrete, and underneath the sheetrock.

In Colorado's climate, we get fantastic temperature swings - 80 during the day, snow that night, etc.... What I find is that with the daytime/nighttime swings, the concrete core stayed pretty constant (say, a 3 degree swing) - Meaning all night, your heat system is working like it's a 60 degree day outside. The converse was true in the summer, where it would warm up a tiny bit during the day, and cool off at night.

While I like the super exterior insulation concrete idea, I did visit 2 homes built this way. My wife wouldn't live in a house like that, is about all I can say..
The first we visited in new mexico, and it was hot as shit (mid summer). I suspect over time, the energy infiltration across the outside foam still allowed the concrete to heat up, to the point that it's warm to the touch (The same way ice still melts in a cooler, just slower). Great during winter (except that it doesn't get warm to the touch in winter, just cold). The second was cold and damp. If you're going to go with an an exterior insulated concrete design, you'd better have a damn good building science engineer figure out your HVAC, dew points, and exchange rates. Here, in Colorado, (low humidity) Pouring vaults built into ICF homes has been popular. Typically, only the exterior side of these roofs was insulated, as they were generally used as wine cellars and wanted to be kept cool - Nevertheless, both of the concrete roofs without a thermal break poured this way had moisture issues during times of the year. My brother wants to build his house this way, in NM, but he doesn't have a wife who wants wall finishes, etc.

My first choice would have been real adobe, double walls, with a 6" insulation between them... I don't know if it's the nature of adobe, and all that baking in the sun, but exposed adobe is much nicer than exposed concrete. There is another ICF based on that thermal principle, but I don't think you can easily make up for double 18" thick walls with concrete.

If you really want the benefit of a thermal flywheel, you need to get energy into that concrete/mass through some means when you are heating, and keep it out when you are cooling. We did in floor radiant, tied to a propane modulating boiler. However, we sized the tubing runs and flows for lower temperature solar hot water, so the boiler can run less.

It's not perfect, but IMHO, much better than stick frame, and IMHO, better than SIPS (which I've helped build a house out of). Definitely do you homework, but I will never live in a stick frame house again.

I'd stay away from rastra, they have leaking problems like crazy. I'd looked at reward, polysteel, nudura, and a couple others. I like how quiet it is - When you walk into an ICF house, you'll know.

My floors and roofing are more traditional, TJI joists for floors, engineered trusses for the roof, entire underside of roof deck sprayed with spray foam sealed to the ICF's..... The more recent IRC energy codes have adopted conditioned attic space as an option when done properly as it A) reduces a lot of penetrations in the roof B) is more energy efficient.

One other caution - In a super insulated house, make sure your HVAC guys know their business... A) they won't oversize the equipment B) they won't rely on guestimates and crap to figure out make up air C) You'll need to budget extra for an HRV or ERV (About a grand) in an ICF or SIP house - Otherwise you won't get the air exchange that even the 'best' stick frame houses have (stick frame gets it through leakage), and when your dog farts, you'll still smell it days later.

This is excellent advice given my limited experience with ICF's.

Honestly, I'm not the biggest fan of ICF's compared to reinforced precast forms - but having a Class-A truck and crane rolling up tends to draw attention if you're trying to keep low profile. That's one of the advantages of ICF's. You can have a concrete truck come in, fill the forms, and drive out fairly quickly. One of the other problems in addition to the interior insulation layer and wiring/plumbing issues is there are many contractors that don't frame it & support it properly. The walls can sway or lean when filled, or heaven forbid you have a blow-out. Also not a big fan of some moisture issues.

Make sure you get a quality experienced contractor for the ICF work. It can be done yourself too, but it's notably faster if you have professionals do it.

TaylorWSO  [Life Member]
3/20/2012 1:02:35 PM

Originally Posted By HomeSlice:
Can you help me understand the internal insulation thing? Most of what I've seen appears to be a 6" concrete wall with 2" of foam insulation on both sides of it.

T-WSO, you don't happen to have any pictures of one of those wiring jobs, do you?

ETA: I'm a little surprised by the reaction here. Generally this stuff is held in high regard in many BOL threads, but I get the feeling you guys who've worked w/ it before have a luke-warm perception... Interesting.


I think JosephTurrisi was the one talking about the wiring, as Ive only seen it done, not done it myself.

Its not that it is not a great idea, but you could do a lot better with a different approach. I would take it over traditional stick build any day, but I dont like giving up the quality of the thermal mass, especially if you think about SHTF

JoeRedman  [Team Member]
3/20/2012 2:02:55 PM
I have been trying to get one built for a while now, and had the troubles mentioned in finding a contractor willing to work with it or that has experience. I am planning a basement and a SIPS roof. My wife loves to take pictures, so I am sure that I will have a 56k-no way page when I get going on it. Still waiting on contractor to get my estimate today, and when I come to after looking it over, I'll see if I can post some more info.
Cpn_Ron  [Team Member]
3/20/2012 9:00:55 PM
Originally Posted By TaylorWSO:

Originally Posted By HomeSlice:
Can you help me understand the internal insulation thing? Most of what I've seen appears to be a 6" concrete wall with 2" of foam insulation on both sides of it.

T-WSO, you don't happen to have any pictures of one of those wiring jobs, do you?

ETA: I'm a little surprised by the reaction here. Generally this stuff is held in high regard in many BOL threads, but I get the feeling you guys who've worked w/ it before have a luke-warm perception... Interesting.


I think JosephTurrisi was the one talking about the wiring, as Ive only seen it done, not done it myself.

Its not that it is not a great idea, but you could do a lot better with a different approach. I would take it over traditional stick build any day, but I dont like giving up the quality of the thermal mass, especially if you think about SHTF


In climates like Oklahoma's, the thermal mass effect does not matter to me as much as the thermal mass of the walls themselves. We have pretty wild temperature swings and the ICF walls will be a huge help in buffering the inside of the house from those swings. You can always go with a poured concrete floor and tile or stone for true thermal mass for passive heating/cooling. I've been looking at the possiblity of using a thin layer of concrete under the entire floor(hardwood throughout, with tile in bathrooms and kitchen). I don't remember the name of the stuff but it is thinner and lighter than regular concrete; most importantly it lets me install pex tubing for a future geothermal system or solar radiant heating.

I plan on sprayed closed-cell foam on the radiant-barrier roof deck and an extra two or four inches of PIC board insulation(possibly with radiant barrier as well) on the outside of the walls. Likely built on a good-sized crawlspace due to the cost of a full basement. With some passive cooling/ventilation features I'm hoping to
severely minimize our cooling needs in the summer. I do commercial automation systems for a living so I'll be building in a bit of monitoring/control for energy management. Well, as much as the budget allows anyway. I've been planning our future build for a couple years now; we have an offer contract pending on some land, waiting for a water well test before we close. If all goes well we might start building in a year or so. I hope.



EXPY37  [Team Member]
3/21/2012 12:42:09 AM
Re leaving bare concrete INSIDE walls in poured wall constuction, I'd never do that.

Like already mentioned, foam board 2" or even 4" insulation on the outside and then 6" 24 ga metal studs on the inside, 7/8" hat channel crossways on 16" centers on the interior surface of the studs to break heat conduction directly from the sheetrock to the stud.

R19+ inside the 6" studs and you will be amazed.

Last year we built a 24 x 20 clearspan room inside a bldg almost like that but it is a freestanding load bearing [with much heavier 6" metal studs] room on a concrete slab and the temperature in there without any heat all winter stayed right between 32F and 42F [a couple times may have dipped slightly below 32] with temps below zero outside lots of times.

This room was inside an uninsulated metal bldg.

The hat channel run crosswise is an important part. I've done that at several locations, cost is minimal and OMG the insulation factor goes way up.

This kind of construction is flexible with no surprises and anyone knows how to do it.

I avoid wood frame construction anymore...



lukus  [Member]
3/21/2012 1:06:42 AM
I built my house about 12 years ago using ICFs. Durn if I can remember the name right now, but they came as large blocks (with 6" diameter holes 8" on center) that stacked and locked together like legos.

I'm in the building industry and have built a dozen other houses, so I did most of the work myself. The screw strips for interior sheetrock were a real pain in the ass and the electrical was a hassle, but overall it was worth it. My electric is about the same as my previous residence at half the square footage. A real adjustment for me is how quiet they are. Birds have to be right outside a window to notice and I rarely hear my dog bark. I also don't know it's raining until it's pretty hard. I feel pretty secure in most storms.

I wouldn't hesitate to use them again. I might go with another system, but I've been very pleased. I've seen several Rastra homes being constructed and I like how they are sandable/shapable with a block wrapped in stucco mesh. I also like how Rastra are ready for hard plaster (no sheetrock) on the inside and stucco on the outside.

lukus
HomeSlice  [Team Member]
3/21/2012 12:39:20 PM

Originally Posted By beakerello:

When are you wanting to build? I have found lots of info, by going to the Home and Garden shows that are usually put on by the Home Builders Association in your AO usually in the spring. You will find lots of ICF vendors at these types of shows.


If we do this, it'll be soon. Rates are as low as we're ever going to see them in my lifetime, so it's pretty much now or never.



Originally Posted By gdawg:
We have built a few homes out of it and it doesn't impress me doing the whole house out of it. Lots of things that just didn't seem right or normal like stick frame construction.

Would you mind expanding on this a little bit? I know it's different, but other than being that, are there issues that aren't obvious?



Originally Posted By HuckMeat:

My cost was a wash because concrete was cheaper at the time and I did all the ICF and foundation work myself.

I was my own GC, most GC's don't like them because they do take longer to get the whole building done. My plumber and electrician were fine with slightly modifying their methods.


Was it a wash w/ you doing the ICF labor vs. a contractor doing stick framing, or your labor on either side of the equation?

Also, I'm a little surprised it would take longer than a stick built house. My gut instinct was that it would be faster. Why do you suspect this is? Maybe because most GC's dont' have a lot of experience w/ the stuff?



Originally Posted By HuckMeat:
I've shot an insert I had to cut out with .308. Bullet created a small pockmark in the concrete, but under the foam, so you almost couldn't tell from the outside that it had been shot. Nevertheless, bullets will eventually get through some kind of concrete, but it's of course, way better than plywood and 2x4.





Originally Posted By HuckMeat:

One other caution - In a super insulated house, make sure your HVAC guys know their business... A) they won't oversize the equipment B) they won't rely on guestimates and crap to figure out make up air C) You'll need to budget extra for an HRV or ERV (About a grand) in an ICF or SIP house - Otherwise you won't get the air exchange that even the 'best' stick frame houses have (stick frame gets it through leakage), and when your dog farts, you'll still smell it days later.

Please help me understand what this is.....?



Originally Posted By EXPY37:

Like already mentioned, foam board 2" or even 4" insulation on the outside and then 6" 24 ga metal studs on the inside, 7/8" hat channel crossways on 16" centers on the interior surface of the studs to break heat conduction directly from the sheetrock to the stud.

R19+ inside the 6" studs and you will be amazed.

I thought the "normal" method was to hand the drywall directly to the foam blocks? Does it need studs and insulation on the inside? or is this an extra layer for insulation value?

Thanks all, sorry for the giant combined post. Felt it better than 10 individual replies...

-Slice


Cpn_Ron  [Team Member]
3/21/2012 2:05:04 PM
Originally Posted By HuckMeat:

One other caution - In a super insulated house, make sure your HVAC guys know their business... A) they won't oversize the equipment B) they won't rely on guestimates and crap to figure out make up air C) You'll need to budget extra for an HRV or ERV (About a grand) in an ICF or SIP house - Otherwise you won't get the air exchange that even the 'best' stick frame houses have (stick frame gets it through leakage), and when your dog farts, you'll still smell it days later.


Please help me understand what this is.....?

I can answer this one. An ICF or SIP is nearly airtight, much more so than a stick-built house. Because of that you will need a source of outside air for ventilation. In a stick-built house(most, anyway) the inevitable cracks and holes provide enough path for sufficient air changes in the house. If you neglect outside air you deal with not enough fresh air to breathe comfortably, moisture and smell issues, etc.

Expect somewhere in the neighborhood of $1k for an HRV or ERV. I'm not familiar with Indiana weather so you'd have to ask a local HVAC guy which would be best for you. Google for descriptions of both, I'd just end up copy/pasting anyway. Cliffs is Heat Recovery Ventilation vs. Energy Recovery Ventilation, one is better in heating climates and the other for cooling climates.

edit: From what I understand ICF's save you 40-50% on your heating/cooling bill, hence the need to not oversize the unit. If the unit is oversized you will pay too much up front, you'll have humidity issues, and the cost efficiency of the unit will be less than it should.
EXPY37  [Team Member]
3/21/2012 2:07:14 PM
Originally Posted By HomeSlice:



Originally Posted By EXPY37:

Like already mentioned, foam board 2" or even 4" insulation on the outside and then 6" 24 ga metal studs on the inside, 7/8" hat channel crossways on 16" centers on the interior surface of the studs to break heat conduction directly from the sheetrock to the stud.

R19+ inside the 6" studs and you will be amazed.

I thought the "normal" method was to hand the drywall directly to the foam blocks? Does it need studs and insulation on the inside? or is this an extra layer for insulation value?

Thanks all, sorry for the giant combined post. Felt it better than 10 individual replies...

-Slice





Extra insulation on a poured cocrete wall [could be used on any type of construction, incl foam block] and it will steal from the interior size. So make the perimeter larger.

Plus most folks would never do this and instead accept an increased heat 'transfer', lower cost, and cry abt it afterward.

txgp17  [Team Member]
3/21/2012 5:21:06 PM
I've been reading up on ICF's for a while now, if and when me and the wife get to build in the new future, we'll use ICF construction for all the exterior walls, and maybe the interal load-bearing ones too, if there are any.
Orion_Shall_Rise  [Member]
3/21/2012 5:24:58 PM
Originally Posted By Cpn_Ron:
Originally Posted By HuckMeat:

One other caution - In a super insulated house, make sure your HVAC guys know their business... A) they won't oversize the equipment B) they won't rely on guestimates and crap to figure out make up air C) You'll need to budget extra for an HRV or ERV (About a grand) in an ICF or SIP house - Otherwise you won't get the air exchange that even the 'best' stick frame houses have (stick frame gets it through leakage), and when your dog farts, you'll still smell it days later.


Please help me understand what this is.....?

I can answer this one. An ICF or SIP is nearly airtight, much more so than a stick-built house. Because of that you will need a source of outside air for ventilation. In a stick-built house(most, anyway) the inevitable cracks and holes provide enough path for sufficient air changes in the house. If you neglect outside air you deal with not enough fresh air to breathe comfortably, moisture and smell issues, etc.

Expect somewhere in the neighborhood of $1k for an HRV or ERV. I'm not familiar with Indiana weather so you'd have to ask a local HVAC guy which would be best for you. Google for descriptions of both, I'd just end up copy/pasting anyway. Cliffs is Heat Recovery Ventilation vs. Energy Recovery Ventilation, one is better in heating climates and the other for cooling climates.

edit: From what I understand ICF's save you 40-50% on your heating/cooling bill, hence the need to not oversize the unit. If the unit is oversized you will pay too much up front, you'll have humidity issues, and the cost efficiency of the unit will be less than it should.



the real key in sizing the unit is cycle time. If you are really efficient it will always be running for short times which kills lifespan and uses lots of energy on startup. You want something that can keep up with the loss by running for a good while not overpowered on and off
Cpn_Ron  [Team Member]
3/21/2012 8:58:38 PM
Originally Posted By Orion_Shall_Rise:


the real key in sizing the unit is cycle time. If you are really efficient it will always be running for short times which kills lifespan and uses lots of energy on startup. You want something that can keep up with the loss by running for a good while not overpowered on and off

That's why I mentioned humidity issues and efficiency. If the unit is short cycling during the cooling season it won't dehumidify properly, even more so with outside air ventilation. It would kill the equipment early as well, like you already mentioned.

Originally Posted By EXPY37:
Plus most folks would never do this and instead accept an increased heat 'transfer', lower cost, and cry abt it afterward.

Are you talking about the 6" stud interior framing? Seems like a large cost increase, essentially a house within a house. Obviously a very high and effective insulation value, though. I'm wondering if I should add an inch or two of XPS or PIC board to the interior, I'm thinking the cost of the 6" framing and insulation may be prohibitive(for me). I was planning on adding additional insulation only to the exterior of the ICF wall.
HomeSlice  [Team Member]
3/21/2012 9:07:28 PM

Originally Posted By Cpn_Ron:

Originally Posted By EXPY37:
Plus most folks would never do this and instead accept an increased heat 'transfer', lower cost, and cry abt it afterward.

Are you talking about the 6" stud interior framing? Seems like a large cost increase, essentially a house within a house. Obviously a very high and effective insulation value, though. I'm wondering if I should add an inch or two of XPS or PIC board to the interior, I'm thinking the cost of the 6" framing and insulation may be prohibitive(for me). I was planning on adding additional insulation only to the exterior of the ICF wall.

That's interesting. I was under the impression none at all was required.

We have 4 real seasons here. Hot/humid summers (sometimes 100+), nice/humid spring, nice/dry fall, moderately cold winters (sometimes but not always well < 0).


Cpn_Ron  [Team Member]
3/21/2012 9:27:03 PM
Originally Posted By HomeSlice:

Originally Posted By Cpn_Ron:

Originally Posted By EXPY37:
Plus most folks would never do this and instead accept an increased heat 'transfer', lower cost, and cry abt it afterward.

Are you talking about the 6" stud interior framing? Seems like a large cost increase, essentially a house within a house. Obviously a very high and effective insulation value, though. I'm wondering if I should add an inch or two of XPS or PIC board to the interior, I'm thinking the cost of the 6" framing and insulation may be prohibitive(for me). I was planning on adding additional insulation only to the exterior of the ICF wall.

That's interesting. I was under the impression none at all was required.

We have 4 real seasons here. Hot/humid summers (sometimes 100+), nice/humid spring, nice/dry fall, moderately cold winters (sometimes but not always well < 0).


No additional insulation is "required" with ICF construction. I am still planning on adding additional insulation with a radiant barrier to the outside. More is better. The radiant barrier part is important too. It's not as much help in the heating season(if the radiant barrier is on the outside, which it will be), but it makes a huge difference in the cooling season.

I'm going to have to do some more asking around and reading about the additional interior insulation. It goes against the information I've come across so far. With only the ICF forms as interior insulation you would still retain some part of the thermal mass effect, more so with added exterior insulation. More to think about....
HomeSlice  [Team Member]
3/21/2012 9:30:10 PM
When you talk about a radiant barrier, what kind of surface are you talking about? We were thinking of putting stone or brick on the outside...

EXPY37  [Team Member]
3/21/2012 10:24:42 PM
Originally Posted By HomeSlice:

Originally Posted By Cpn_Ron:

Originally Posted By EXPY37:
Plus most folks would never do this and instead accept an increased heat 'transfer', lower cost, and cry abt it afterward.

Are you talking about the 6" stud interior framing? Seems like a large cost increase, essentially a house within a house. Obviously a very high and effective insulation value, though. I'm wondering if I should add an inch or two of XPS or PIC board to the interior, I'm thinking the cost of the 6" framing and insulation may be prohibitive(for me). I was planning on adding additional insulation only to the exterior of the ICF wall.

That's interesting. I was under the impression none at all was required.

We have 4 real seasons here. Hot/humid summers (sometimes 100+), nice/humid spring, nice/dry fall, moderately cold winters (sometimes but not always well < 0).





Doesn't have to be 6", it can be 4" metal studs, with the hat channel horizontally, there's enough space for R19 IIRC. Flimsey 26 ga studs and hat channel aren't expensive.

Or use 1 1/2 or 2 inch foam board insulation but it isn't as good as the above, more $, but quick to install.

If budget is a concern, add insulation to the sunny side of the house in warm climes or the north in cold climates.

The freestanding room we built like this is pretty much controlled in temp by the slab. In winter carpet can be added to insulate the floor and in summer could be removed for cooling if heating/cooling energy were ever an issue [that it will likely become]

As far as short cycling of heating or cooling, that's essentially a function of heat or cooling equipment sizing. So many ways to skin this cat efficiently, it's dependent on specifics.

Also, controlled shading of the sunny side of the building can do a lot to add or limit heat into the structure.

As far as the structure being tightly 'sealed' if you want air from the outside, add an intake to the HVAC, it's req'd by code most places anyhow.

Add a fan in the bath to draw humid air out. Replace by cooled dehumidified air in the summer.

If it's humid outside, damp the vent [automatically, cost isn't much any more if you're creative and think]

Think abt making part of the sunny outside surface a hot air heater to circulate warm air inside as appropriate. There's an amazing amount of heat available in a 10 x 10 foot area on a cold and sunny winter day.


Cpn_Ron  [Team Member]
3/21/2012 11:45:24 PM
Originally Posted By HomeSlice:
When you talk about a radiant barrier, what kind of surface are you talking about? We were thinking of putting stone or brick on the outside...


A radiant barrier is basically metallic foil. You can get roof decking with it on one side, foam insulation boards with it, etc. It's important to use metal tape and try to have complete coverage. The radiant barrier will reject radiant heat and insulation helps slow/block the rest. Check out this Department of Energy page, Radiant Barriers, for some more info. That's just from a quick google search, there is a lot more info out there. Radiant barriers block about 95% of radiant heat.

ETA: I did a lot of reading at www.buildingscience.com. I think it is a great site to learn about energy-saving building methods and their pros and cons.
HomeSlice  [Team Member]
3/22/2012 12:03:57 AM

Originally Posted By Cpn_Ron:
Originally Posted By HomeSlice:
When you talk about a radiant barrier, what kind of surface are you talking about? We were thinking of putting stone or brick on the outside...


A radiant barrier is basically metallic foil. You can get roof decking with it on one side, foam insulation boards with it, etc. It's important to use metal tape and try to have complete coverage. The radiant barrier will reject radiant heat and insulation helps slow/block the rest. Check out this Department of Energy page, Radiant Barriers, for some more info. That's just from a quick google search, there is a lot more info out there. Radiant barriers block about 95% of radiant heat.

ETA: I did a lot of reading at www.buildingscience.com. I think it is a great site to learn about energy-saving building methods and their pros and cons.


From Link Above

Reflectivity (or reflectance) – a measure of how much radiant heat is reflected by a material. It's also expressed as a number between 0 and 1 (sometimes, it is given as a percentage between 0 and 100%). The higher the number, the greater the reflectivity.

Are you saying I need to wrap my house in tin foil?


Cpn_Ron  [Team Member]
3/22/2012 12:36:05 AM
Originally Posted By HomeSlice:
Are you saying I need to wrap my house in tin foil?



Well........yes.

ETA: And don't leave any gaps. Wouldn't want any radiation to get through. You know, the thermal kind.
HomeSlice  [Team Member]
3/22/2012 1:12:14 AM
That's some funny shit right there. Thanks for the laugh!

I'll run that by the wife and see what she thinks...


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