Hello,
I am planning an ICF house, and I was also planning to use fiber cement siding for portions of the exterior (fake stone for the rest). Neither James Hardie or Certainteed have any website instructions for installing their fiber cement siding on ICF walls, so I wrote to both of them and asked. Both of them more or less said that they do not recommend their products for use with ICF walls.
This seems strange because I thought I read on Breaktime or JLC about this combination being used, but maybe I am wrong.
Anyway, is there a solution for fiber cement siding and ICFs that would work well?
Thanks
Replies
gerrha,
You would have to screw the hardie planks into the screw strips.. some brands have screw strips every six inches, some have them further apart.
It will be slow, frankly I would look carefully at using real stone or brick over hardie plank.
I'm a do-it-yourselfer and I looked only at the cost of materials and it was close enough for me to prefer real over fake..
Watching the pros do it next door I think the time it took was similar as well. (and I am not a mason by any stretch of your imagination)..You can see my work if you go to 94941.1 in the archieves..
If you have a certain look in mind and hardie plank and fake stone are the only solution then of course that's what you can do.. around here though the increased market value of stone and brick is significant enough to offset a higher cost..
Thanks for the reply Frenchy,
If I understand what Certainteed and James Hardie are saying, fastening their products through +/- 2.5" of EPS to an embedded screw strip is not recommended due to pull-out requirements, and doing so might be impossible to get past an inspector.
And, you have brought up another subject that I am now afraid to think about. If there are issues with fastening something as simple (I thought anyway) as fiber cement siding to an ICF wall, what about putting stone on it, fake or otherwise - especially in a seismic location like western Oregon?
Gosh, what to do now?
gerrha,
those screw strips are pretty solidly connected.. when I put my stone on mine I used a brick tie with a fine threaded screw (instead of coarse threaded sheetrock screws) I can now crawl up my wall on those stones and I weigh 270 pounds!
I first became aware of just how sturdy this fastening method was when I installed my circuit breaker in the wrong location.. With only 4 screws holding it in place I figured it would be extremely easy to pry off the wall and move it to where it needed to go.. After all I had a 8 foot long pry bar that I used to move heavy granite stair stones around..
I mean what's 4 screws compared to hundreds of pounds of granite?
Well it held so well and I grunted so hard that my heavy duty pry bar now has a slight bow to it.. I did finally move it, by unscrewing the plywood and moving it rather than pulling the screws loose.
I have seen ledger boards attached to it that held the second floor up so I suspect that the engineering behind them is pretty impressive..
I don't know that the metal connectors would be as tough, I only have experiance with the nylon ones..
By the way, if you put sheetrock on from the inside the screws will pull right thru the sheetrock just like 2x4 stud will. but since the strips are every 6 inches it's easier to hit the "studs" with ICF's than with wood studs 16 inches on center..
I would guess that the resistance to pull out of screws in ICF's is about on par to the resistance of pullout of wood studs.. The fact that you can be so much closer together is a bonus..
When you add siding to ICF walls, the right way to do it is to use strapping and screw it to the ICF at the recommended locations, then nail your siding to those furring strips.
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Piffin & Frenchy,
I agree with what both of you are saying. I was always planning to use furring strips for the siding and I am sure screws in the plastic strips in the ICF wall are very strong if correctly done. The thing is, the two primary manufacturers of fiber cement siding seem reluctant to recommend (and probably to warranty) their products for use on an ICF wall.
Doesn't this seem strange? Would you use it yourself anyway?
Doesn't seem strange at all.As I understand it, the concern of the cement siding manufacturers is that it not be allowed to remain wet. If the siding absorbs water and then freezes, it will support mold growth and delamination from freezing.I can envision where moisture is locked on the back sides of the siding if it were to be installed directly over the ICF foam, but with the drainage plain, there is no call for concern
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Hello Piffin,
It seems their concerns are all associated with pullout resistance, see below. When I read these, I get a bad feeling that fiber cement and ICF do not mix, in their mind at least. Do you get the same feeling by reading these?
Thanks
From James Hardie: You will have to screw it in with a size 8 or bigger corrosion resistant screw in accordance with our installation guide. It is on the ICF manufacturer to demonstrate that their attachment system is comparable to what JamesHardie¯ has published within NER-405 Table 2A and 2B. In doing so they have to convince the building inspector that their ICF attachment system is equivalent in pull out resistance to a Number 8 1-5/8” long X 0.323” head diameter ribbed bugle head screw into a 20 gauge X 3.62” X 1.375” Metal C stud. The fastener should have the same or larger head diameter to prevent product pull through. The fastener also has to be corrosion resistant.
From Certainteed: CertainTeed can not recommend installing fiber cement over foam that puts the siding 2-1/2” out from the point of attachment (the “plastic fastener surface”). The weight of the siding would not be supported by the fastener sticking out that far. You should contact the ICF manufacturer to determine what fasteners can be used to fasten into their plastic strips. They should be able to provide fastener load information (ie: withdrawal resistance). We can provide information as to the types of fasteners typically used with fiber cement and the siding weight, but we wouldn’t be able to determine what fastener would work with the specific ICF system.
gerrha,
That seems to be the usual boilerplate shipped with anything. It might help you to understand that the Hardieplank isn't really hanging off the screws as stated.. what happens is the screws clamp onto the foam. clamping power is what holds things in place.. While you can easily compress foam with a thumbnail or finger. spread that same load over many feet and foam is at least as strong as builtrite or other approved wallsiding units..
Franchy, have you any experience with hanging Hardipanels off ICF. I have a client that wants that and I'm not rethinking my plans.
jimfka (formerly known as) blue
JimAllen,
I've seen it done, I haven't done it myself.. I used stone and timbers outside mine..
go to 94041.1 for photo's..
That represents absolutely no problem whatsoever for me. I would be using #8 GRK screws anyways thru the strapping and into the ICFsWhat confuses me is this -
"that puts the siding 2-1/2” out from the point of attachment"The point of attachement is immediately under the surface of the ICF and some brands have it exposed on the surface. These are not plastic but a composite made for such screw attachments. Some brands like Polysteel use a steel instead of the composite equivalent to metal studs.If the4re were the slightest amount of question, I would use PL 300 under the strapping to glue it to the foam also.Then they could get a D9 and go ahead and test their pullout resistance. The wall would be likely to fall over first.
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Hi Piffin,
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Thanks for the help. I am trying to put all of this together and still have several questions.
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Ok, from the exterior ICF foam outward:
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1. First layer? Would you use any house wrap or water barrier?
2. Next would come the vertical strapping at 16” OC. What exactly is the strapping? Is it wood or metal? I was planning to use Buildblock ICF, and their attachments are at 6” OC, so I am not sure how to work around a 16” OC vertical strapping distance either.
3. For extra margin of safety, glue the strapping with PL300. Screw it to the ties with #8 GRK screws. Which screw would you use?
4. Would you put another layer of house wrap over the vertical strapping? Certainteed’s installation guide shows a layer used over the strapping when their product is used with strapping.
5. Finally, the fiber cement siding is screwed to the vertical strapping. Again, which screw would you use?
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A lot of questions there, but I do appreciate the help.
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Glueing strapping to the house wrap would be pointless. The strapping would be stuck to the wrap only, like a big slip sheet that is only stapled or cap nailed to the ICF wall. No direct contact between the strapping and wall, so the glue would add nothing to increase the adhesion of the strapping to the ICF.
Dave
Yes, you are correct. Should have figured that out myself, pretty dumb to glue to the paper.
negative on the house wrap. If you need it, you did a major mistake on the ICF pour.Strapping is something we can buy at the lumberyard.
Spruce KD 1x3 material. If yours does not have it, typical 1x4 or rip a 1x6 in half.Run the strapping at 12" OC to align with the ICFsGRK for screws.
the multi-purpose R-4
You can get it in stainless too
http://www.grkfasteners.com/en/R4_1_2_information.htm
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I think I got it. No housewrap next to foam or between siding and strapping.
Thanks Piffin
Hardi on ICF is a PITA at best. As Piffin said the correct way would be to strap and nail. The blocks I used had the internal staps that stopped about 1 or so from the top and bottom of each block row (2' tall blocks). Wouldn't you know it that two laps fell right on that seam. What a pain. As for the screws, before starting I contacted Hardie and they recommended the modified truss head screw. For the most part they work well...but slow.
We "fake rocked" a couple of walls, and it's really odd, if you tap on the rock, it sounds hollow and you'd swear it would just fall off....but it seems to be attached firmly.
If I were to do it again...I believe I'd go stucco rather than Hardie.
I don't mean to hi-jack this thread so I'll be brief.
How did you set your synthetic stone to the ICF?
I went to siminar a few years ago where the recomendation was felt paper, wire lath, scratch coat, then butter stone.
I ask about installation over ICF then, but never got an answer.
Appreciate any insight.
Dave
Dave,
that's typically the way it's done the wire lath is screwed on Vs nailed on..
Thanks frenchy
your stone over ICF prep would look something like this. The photo here shows for stucco, but same -o- same-o
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What is used, in that picture, for the flat washers and the means of attaching the lath? I'll be stucco-ing my ICF basement walls in the spring and I want to do it right.
I always seem to have a few handfulls of the discs used for placing insulation on roof decks for gluing EPDM down. They are pretty handy for stuff like this too. Run the screw through.at risk of going overboard - you should NOT use sheetrock screws, even if they are galvanized.;)
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Piffin, do we have a consensus here regarding placing Harid panels (4' x 8') over ICFs?
Am I reading that Hardie and the ICF folks don't/won't warrant it?
If strapping is used, would it be 1x3 run horizontally on 2' centers with blocking under each vertical joint?
Or, for water purposes, it would be better to put the strapping vertical every 16" oc? and leave the bottom open with a screen for drainage? This seems like it defeats the intention of using ICFs in the first place. Essentially, we are "studding" the entire structure anyways, labor wise.
What about gluing and screwing the Hardi Panels direct? Is that causing a mold trap?
I'm in Texas now and I've got to understand this. No one would ever ask me to do something like that in MI, LOL.
fka (formerly known as) blue
"This seems like it defeats the intention of using ICFs in the first place."You may have a different intention in using ICFs than I do_ For superior insulation
_ because when I have to do the form and pour, it is easier for me than building forms.Neither of those has any conflict with strapping over the ICFs.Anyways, I would run the strapping vertical.
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I'm not the guy buying the ICFS. One of his stated intentions was to build something that the termites wouldn't eat. Thus my comment about adding the straps.
I was thinking that vertical made the most sense too. Thats what I intend to propose in light of seeing this thread. Thank you boys!
Anyone got any good source for insect screens at the bottom? I was thinking of corevent, but I thougt that was a 1" product.
jimfka (formerly known as) blue
Jim, Scroll down and look at "strip vents" couple of different sizes available. http://www.cor-a-vent.com/ventilation-products.cfm Or look at this: http://www.cor-a-vent.com/siding-vent-sv-3.cfm They can't get your Goat if you don't tell them where it is hidden.
Edited 10/11/2007 1:14 am by dovetail97128
For the termites, I guess you want to use PT lumber for strapping
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JonE
EIFS type stuccos are better than the old fashioned on ICFs. You've got the foam surface. EIFS is made to bond to foam. Forget the metal lath, too. Glass mesh is the way.
Ron
I noticed the ice and water shield under the lath rather than 30# felt. Is that just extra protection?
My design calls for a synthetic stone from grade to the bottom of the windows, above that is EIFS. The foundation is ICF with standard framing above it, so only a foot or so of lath will be lapped over the ICF.
A picture is worth a thousand words,..... thanks.
Dave
On the photo, two thirds of the wall was to be below grade in a wet area, so we used the Grace for water barrier. That would not be needed above grade. I would not even use the tarpaper above grade. The reason for tarpaper is over a wood framed wall. You do not want the dry wood sucking the moisture out of the mud mix before it cures, so you isolate the wood from the mud. It also keeps rain from penetrating the wall assembly.With the ICF foiam, you alreaddy have a surface that is impervious to moisture so the mud will cure fine in direct contact.I notice that somebody else pointed out that you do not need all this. The EIFS syntheticc stucco is easier to do if appearance is primary consideration and I use it also, but for this particular job, we needed something that would stand up to nicks and picks so real stuco was called for.
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We didn't add the felt paper, the rest is good. Depending on what block you use, and how long it's exposed to the sun, before applying the lath, broom the face of the Styrofoam, soft broom but pretty vigorous. If the block has the thin layer of powder from UV degradation, it will keep the scratch coat from adhering well. It's amazing how well the scratch coat sticks to the foam.
McFeely's makes a stainless fiber cement screw - I blind screwed my planks to the icfs, no drainage plane. I didn't enjoy the Hardie product, but the screws were the bees knees.
ICF and fibre cement siding
Hi,
I've searched the forums and found refernce to the topic but somehow have not been able to find post #94941.1 (2007)
I would like to use fibre cement sheet exterior on ICF wall and was wondering how these projects in the forum worked out.
Are there any photos?
Thanks