My new home in Michigan will have closed cell insulation sprayed on the exterior of the poured walls from sill plate to footings, and part of it will be exposed between the ground and the Hardie siding. What typically goes on this for aesthestics?
It is a sloped area from front to back, and I imagine over a length of 20 feet or so the exposed material is about 4-5 feet high. The siding will step down following the slope’s contour but not go all the way to the ground.
I just read an article in FH about using laths and chicken wire and so forth, but I would like to just spray a paint or something on it. Stucco, stone or brick would look out of place given the location on the house and the rest of the exterior finish. Sprayed foam is not smooth like sheets, obviously. Thanks for any input!
Replies
How about concrete tile backer board glued to the foam and finished with a screed coat of concrete stucco. Don't forged a metal termite shield at the top under the sill plate and extending over the foam.
Concrete board is not for use in full ground contact
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but ya didn't tell him why...
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Short answer - the manufacturer says so.So I asked whyIt will wick water and delaminate.
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shorter answer...
discovered it was an expensive no go...
and if it freezes.... it's history..
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
shorter answer...
discovered it was an expensive no go...
and if it freezes.... it's history..
IMERC, are you referring to the closed cell spray here? What happened when it froze, and in what stage of the building process did it happen? Thanks.
I was referring to the cement board sheets...
as for the foam...
in continious contact with water the water will infiltrate... water freezes and expands.. so after time it breaks down...
seen this on foam that has been exposed to the elements during rehabs or repairs....
also UV raises cain with the stuff...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
IMERC was referring to the concrete board material that somebody suggested using to surface your foam. It will wick water up when in ground contact, then that water freezes and delaminates the material, so a couple of seasons later, it needs replacing.On the surface, it is easy to assume that since it is concrete it will be fine.
True that it won't rot, but other things happen to man-made materials. They each and all have their pros and cons.
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Piffin,<!----><!----><!---->
When you say cement board is not to be used in direct ground contact, are you referring to a specific brand or does that apply to all cement boards?<!----><!---->
The reason I ask, is I used Durarock on a few houses about 8-10 years ago and on one of them I had an opportunity to come back and cut in additional egress windows. I saw no deterioration in the Durarock that was installed. That cement board would have been about 7 years in the ground at that time<!----><!---->
I will admit to not reading any instructions that would have warned me not to - isn't that the great American male way of doing things?<!----><!---->
I haven't used that method a lot over the years, as it is pricey (just as IMERC said).<!----><!---->
Terry<!----><!---->
none that I know of are intended to be used in full ground contact. I checked my suppliers a couple years ago when I wanted to do just this sort of thing and they all came back negative. That doesn't mean you can't get away with it occasionally with good drainage and no hard freezing, but I wouldn't bet my rep on it.
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so why spray it on there? Sheets are less expensive and have the smooth face.
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I haven't seen anyone spray foam on the exterior of a foundation. It makes me wonder if there are going to be any compatibility issues with the foundation sealer used here. It's an oil based sealer thats sprayed on.
I have seen the sheets used before. A stucco finish was applied later.
Woods favorite carpenter
seen it sprayed below gound elevation...
wunder how that held up???
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
This reads like somebody who is trying to re-invent the wheel as he rolls down the road and still hasn't figured out where the potholes are but doesn't have any brakes...So he still needs a steering wheel, a road map, and a windshield to look thru
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Michigan codes were supposed to be changed to where sheet foam had to be applied to the exterior of the wall.
Last I had heard it wasn't introduced yet.
Spray foam would be a big expense for very little gain, but what do I know. You've had to correct me a few times lately. Woods favorite carpenter
It's not you I am correcting here, for sure.My bet so far is that this guy has a third of the knowledge he needs and is being buffaloed by a spray foam installer ( gee - I hope it IS closed cell foam) who sold him on the idea. He probably thinks that because closed cell foam is mostly waterproof, he is getting two for one and skipping the foundation waterproofing.Saved that step in an unconventional way, but has now created another problem or two, like how to finish it and how to keep the insects out of it.Gunnite sprayed on and troweled smooth is the answer to his Q, but each solution to a previous problem is getting more and more expensive.
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My bet so far is that this guy has a third of the knowledge he needs and is being buffaloed by a spray foam installer ( gee - I hope it IS closed cell foam) who sold him on the idea. He probably thinks that because closed cell foam is mostly waterproof, he is getting two for one and skipping the foundation waterproofing.
I feel like Grandpa in the room with people around him speaking about him in third person! I really do not care to re-invent the wheel at all, and I may have bitten to hard and quick on the sprayer's pitch (it is closed not open cell). But locally the builders I speak with think anything beyond code minimum is reinventing the wheel, and I am trying to get my builder to think about what's best, not what's habitual. I may have stepped in it on this one, and I still have day to choose NOT to spray the exterior.
They already sprayed the waterproofing, wouldn't skip that.
Aside from expense, I have read suggestions here of it being unfit for exterior use and being exposed to the elements. Anyone have supporting evidence? I am not sure I have evidence to the contratry.
Let me just give a bird's eye view of this situation. BTW - I'm a superintendent, which means I build homes, but I'm not the one who puts out the money... "The builder" stops by every few months just to see how it's going.
Your builder has given you some specific advice, but you want to try something more innovative. He knows what is tried and true because he's done it before - presumably many times. You want a better than standard home. Commendable and who doesn't. The thing is you want to be on the leading edge of building technology - not the bleeding edge. Sometimes it's difficult to determine the difference.
It sounds like a spray foam contractor has sold you on the idea of straying foam on the outside of the foundation. OK - but he hasn't been able to tell you how it is to be finished - covered up.... Here's what you need to think about... often times subcontractor's just don't have the whole picture - the big picture. That is why you hired a builder - that is his job.
No way I'd spray foam on the outside of the foundation without going and looking at one that has been done and seeing how it was dealt with. Call the spray foam contractor - ask him for addresses. Take some pics - I'm sue we would all like to see them so we can learn something.
BTW - even if you have them spray the interior of the foundation you are still going to have to cover it with something substantial - to meet flame spread and smoke requirements.
In the mean time I have some Qs: If foam were to be sprayed on the outside of the foundation how thick will the foam be? Will the house mud sills be set out by that amount to make the siding more or less come out flush with this exterior foam layer on the foundation? Has the foam contractor said that the sprayed on foam will come out nice and smooth (a uniform layer), or will it be more of a + or - 1/2" kind of deal? If it is the latter(+-), and you have some kind of protective coating sprayed on, how will it look?
Edited 1/3/2008 8:16 am ET by Matt
"BTW - even if you have them spray the interior of the foundation you are still going to have to cover it with something substantial - to meet flame spread and smoke requirements."guess it depends what you consider substantial. We spray it with firefree88, all it takes to satisfy the requirements
Barry E-Remodeler
>> We spray it with firefree88, all it takes to satisfy the requirements <<
That's really interesting. I haven't hear of that product. I found their web site:
http://www.firefree.com/
What is the stuff like to work with? Does it go through a regular airless paint gun? What is the approximate thickness of the coating applied? What is the cost?
yep sprays like paint, they were using a 395 pump. I'd have to check but the last one the sprayed the crawl space, about 1100 sq ft and i think they charged me 250.00 L&MI did have to take the specs to the BI on the first job for them to approve, but no problem since then
Barry E-Remodeler
Matt, thanks for the reply. Your summary is dead on. Breaking new ground with my head is a bad idea.
It is now officially a moot point, because they tar sprayed the foundation and the foam cannot be sprayed onto that. I am glad--saved a bad decision on my part.
2" foam board with borates on outside below grade, insulating from the inside above grade is what builder and I have discussed. Thoughts?
>> 2" foam board with borates on outside below grade, insulating from the inside above grade is what builder and I have discussed. Thoughts? <<
I'd say that is the way to go. The sprayed foam on the inside, especially in the rim joist area would work out well. The rim joist area is a very difficult area to insulate properly and is very prone to air leaks. I'd still recommend getting a borate treat spray foam product though.
BTW - is this a basement? I assume so... If it is, and you spray foam on the inside, you still need to think about how the interior would be finished - even if there is not plans to do it in the immediate future.
Thanks, Matt. Basement with a walkout, so one full wall is on grade. The basement will be finished eventually but used by the kids from day one. We plan to spray foam the rim joists and the sill area from the inside. I am concerned about the heat loss from the slab vertically through the part of the sill that is not sprayed from the inside. The thin foam gasket used under the sill plate can't really do much but maybe keep out some H2O, so getting that area well insulated seems to be a trick without spray foam. I am open to all input as I read up on it.
For interior finish I will furr out and drywall.
Are you referring to the walk out part of your basement?
If so then the best defense you can have is proper drainage. Make sure the exterior grade is 6" minimum from the bottom of the treated bottom plate.
On our spec houses in MI we would pour a slab outside the door that dropped 6" down. In that slab we installed a drain that tied into the houses drainage system. Slab had a 1/4" per foot drop on its way away from the house.
Your doors are the weakest point in a walkout, we found that a $200 slab was a cheap fix for water infiltration.
Woods favorite carpenter
Matt, the walkout wall isn't really an issue--it's the vertical concrete I was mulling over. There will be a slab outside the walkout door graded away from house, and the framed wall will be closed cell spray foamed like the rest of the framed walls in the house.
My builder has been very busy for about 25 years, with many beautiful homes in west Michigan, but we are learning together about energy efficiency and newer ways of doign things. There's a lot to learn (and unlearn)!
I believe you said you were going to finish the basement.
Do a search here on that, Piffin or others might go into detail on the best approach to it.
We use 1-1/2" sheets of foam on the inside, looks like coffee cup foam. Expanded maybe. Attached to the concrete with a foam gun. Then frame walls in front of the foam. insulated with fiberglass.
The floor in your basement will be cold at times. Making the basement a few degrees colder than the upper floors. Look into putting it onto a different zone with the furnace, or putting down an insulated subfloor.
I'm not sure what stage you guys are at in construction so the subfloor might be time consuming if the stairs are already done.
What part of West Michigan are you in? I'm about 30 minutes east of Kalamazoo. Woods favorite carpenter
Matt, we're gonna finish it eventually. The slab will be well insulated and so will the walls. I am thinking 1-2" foam on the interior walls as well. We'll have it set up for radiant heat in the basement, and forced air vents to in the basement to use until we hook up the radiant to a heat source.
Radiant heat is a great idea for a basement slab.
I wasn't sure if you were past that point yet or not.
You are making the right steps to getting a house you'll be comfortable in for many years to come.
Good luck on your project and welcome to BT.
Post some pictures in the photo gallery for us. We like those.
Woods favorite carpenter
Matt, we'll isulate the interior walls and slab with 2" foam. We will have heat runs for the basement until we hook up the radiant in floor heat to a heat source. The house will be zoned on all floors.
We're in Ada.
Isn't Ada outside Grand Rapids?
>>We will have heat runs for the basement until we hook up the radiant in floor heat to a heat source.<<
During construction you might look into doing the opposite. Furnaces suck up all the dust and debris that flies around while work is being done. Using the radiant would help cure that, and more than likely keep the house warm enough for work to be done. Woods favorite carpenter
Yep, just outside of GR.
The radiant will not have a heat source or hookup until a year into living there. If I am lucky I will have the extra +/- $3500-4,500 to get that done as I complete the home, but not likely. I'll insulate and run the pex before the slab pour and get it running as budget allows. In the mean time I can use the furnace with decent comfort, and a space heater now and again if necessary. Or I'll wrap up the little rug rats in warmer clothes like I did as a kid and tell em they're lucky to have any heat at all!
minor point:
>> Make sure the exterior grade is 6" minimum from the bottom of the treated bottom plate. <<
How about 6" minimum below the siding? - which generally hangs an inch or more below the treated plate....
Most siding in our area is vinyl, hangs down about 1/2".
So either would work, so long as you don't exceed 8" from the top of the slab to the top of the door threshold. Woods favorite carpenter
another regional thing - we aim for 18"
Snow get deep here
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Agreed. Our code specifies a minimum of 6" of foundation showing. I instruct my landscapers to leave a minimum of 8" at backfill time (which is before siding) and that way I'll be sure to have at least 6" when it's all said and done.
During the 12 or so years that I lived here we had real snow like 3 tiems. :-)
Edited 1/4/2008 6:15 am ET by Matt
Do termites live in that area?
Not many termites to speak of. Lots of carpenter ants, though. The borates should handle both of them.
I'm not current on this, but when i was researching it a few years ago trying to decide what kind of foundation to build, i read that borates are water soluble and can leach out if they come in contact with water. Journal of Light Construction had an alarming article a few years ago on providing a foam highway into your house for termites/ants.
Edited 1/4/2008 7:34 am by splintergroupie
sorry to talk over you. Don't leave the room to go to the bathroom or you will miss something here.
;)
Looks like my assumption was at least mostly right on thoughThe reason some things are habitual is simply because it is best. For the value at least.Unique shapes like dome homes can be done with exterior spray but there is no need to spend twice as much money for spray application in a place where it creates more problems such as how to coat it over with a smooth surface as you ask here. For smooth straight sides like a cellar wall, use the sheets glued on with PL300, cap at the top with copper flashing, treat with borates or stronger if you have insect problems in your area and trowel on the elastomeric coatings or synthetic stuccoes made for this.To spray and then get to a smooth finish, you have to fill voids or carve the surface to remove insulation you just paid for. Filling voids pretty much means a three coat stucco on wire lath.
Alternatively you can do it with gunnite, but then you are talking real money.
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The foams gonna fail! Why would anyone spray the foam on the exterior? Duh
-Lou
The foams gonna fail! Why would anyone spray the foam on the exterior? Duh
The same reason thousands of buildings used asbestos--they didn't know any better.
Westmich:I am building a new house in Wisconsin. I came across a similar scenerio as yours.I wanted my house to be as energy efficient as possible, comply with codes and not cost me an arm and a leg to build. Here is what I settled on...We are installing an "energy wall" on the inside of the basement against the concrete walls (I have a walkout basement so I actually only have two walls that this applies to). The 2x4 studs are held out from the concrete wall about 1/2". I am going to spray about 2" of foam in against the concrete and then sheetrock over it.I did this for a few reasons.....
1.) It was about the same price (maybe just a little more) as it would have been to install 2" foam to the exterior of the cement.2.) I did not want to mess with holding the sill plate out to match up with the exterior foam.3.) I did not want to apply stucco or anything else to the outside of my house.4.) I need the interior wall anyhow to have finished rooms in that part of my house.5.) Wisconsin now requires an "energy wall" on the inside or foam on the outside.6.) I did not want to install fiberglass bats or cellulose in the basement wall due to any possible moisture problems.Hope that helps you out.
Jurassicjet, thanks for the post. The dummy walls have been discussed here a lot, and I like the idea. Only downfall I can see is losing the 6" of floor space in each finished area--might interfere with my door placement and other things, I'll look at the plan.
For the exposed exterior foam, I'd cut it off above grade. Also insulating the interior as well as foaming the sill area and rim joist box would make up for the heat loss form the concrete walls above grade. You end up using a total of 4" of foam, but the cost is not that great.
Lived in WI for 10 years--Madison and LaX.
You don't need to lose 6"2" for foam. Then you can use straping/furing strips on top of the foam.Or use Wallmate, with has slots for 1by furning strips.Or use metal framing and build a 1 5/8" wall.You will endup with 3-4" walls..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
why not insulate the concrete block walls? in central ny (syracuse) we use foam in the block. this won't work with poured foundation in which case an inside wall is best.
I don't think he mentioned block. He said concrete.
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last i knew the were concrete
yes but a concrete block wall is called a concrete block wall. A concrete wall is called a concrete wall
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are you saying they don't use cinder blocks any more???
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
relax. warm weather is coming.
in August for apoximately 3.14 days and not to expected to run concurrently....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
Where is "O-Wn-Koots"? Sorry, I'm a little slow but pretty accurate :-)
extreme NW Colorado...
it's an area and not a town...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
Edited 1/5/2008 8:49 am by IMERC
I looked it up on mapquest. I brought up a map of Colorado. Recentered it on NW Colorado. Zoomed in about 1/2 way. Screen came up blank white. Hummmm....??? Zoomed out 2 knotches. Ahh - there we go. Blank screen was caused by there weren't NOTHIN' around there. Must suck when you just need 3 more finish nails to complete the job...
that it does...
if it ain't on the truck...
we don't need it...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
Does the applicator of the foam have any specifications for the use of his foam on exterior applications?
Most of the applications of spray applied close cell foam that I have observed show signs of degradation from U/V, weather, hail, insect and rodent infestation, squirrel and bird damage, or mechanical from mowers/trimmers.
As previously suggested....sheet foam would be more easily over coated with Dri-Vit or a parge over lath. But I would suggest borate treated foam for the exterior/sub-surface applications.
Why not apply the foam sheets to the interior of the wall? Leave the concrete exposed to handle the elements and critters...paint it if you wish.
Just an opinion.............Iron Helix
What got me on the discussion with the spray foam installer was the seamless seal from sill to ground. We have all likely read the old study/studies showing that heat loss through the top of the poured wall and the brick veneer all but destroyed the gains achieved through insulating the vertical areas. As I write this I realize that doesn't mean you have to spray the whole thing--maybe just the sill area and rim joists?
The builders on this forum all have worked with clients like me who try to get cutting edge stuff done, who step in it more than not, and can be a royal pain in the *&% for the builder. But when the builder wanted to put FG batts in the walls and attic and call it good because it's cheap, I started to ask a lot more questions...which landed me here. I just want to do what's right for the house.
excellent post... it's good to have a thinker come in...
have you considered tiger foam on the interior of the rim???
spray foam exposed to the elemnts just doesn't last.. this is from observation...
consider what ever your frost line is to be part of the elements...
here it's 120 inches...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
"As I write this I realize that doesn't mean you have to spray the whole thing--maybe just the sill area and rim joists?"You are on the right track there. controlling the infiltration is a major part of a spray foam job, but it is done from the interior at the places where infiltration happens. No air is going to be leaking through the concrete wall underground.Your best, least expensive insulation job heere would be to glue the foam panels to the interior of the foundation wall, attach furring strips over that for the sheetrock, then sporay foam at the top of the wall at the sill and rim joist. A little bit of it over the foam panels between the furring there is fine too. Matter of fact it is overspray there and free, more or less.
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Piffin, I already contracted for the framed walls and attic to be spray foamed, and I am happy with that decision. I am also doing 2" of borate-treated XPS under the slab and between slab and vertical walls, per suggestions form this forum.
Regarding below-grade portion of the foundation walls, I have read that insulating the exerior of the foundation might be a better way to go, but that doing as you state with the foam board in the inside is also acceptable here in the chilly climes.
If the foundation is not yet backfilled and you were not building with SIPs or ICFs, would you foam outside or inside the slab on your own home? I have about 1 day to decide, but realize that either way it is far better than doing nothing (like the houses I have lived in forever). Many thanks.
2" rigid foam board on the exterior below grade rated for that application...
here it's mylar filmed blue....
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming<!----><!----><!---->
WOW!!! What a Ride!Forget the primal scream, just ROAR!!!
I would foam below grade closed cell sheets EPS or XPS and backfill, then insulate interior as well, but if budget is a problem, only insulate top half interior. oulds do the spray foam interior above grade
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That's exactly the plan--merci bucoups.
"But when the builder wanted to put FG batts in the walls and attic and call it good because it's cheap"FG batts is the worst kind of insulation I know of and it is not even cheap. I can get chopped FG BIBBs or denspak Cellulose installed for about the same price but far better performance.With the cost of energy going out of sight, there is no wiser choice to make than a quality spray foam install. Corbond is what I use when the customer can afford it.There are other advantages too. Customers like the "quiet house" effect in particular
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