How to install foam board over clapboard?

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TonyGunz
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How to install foam board over clapboard?

Post by TonyGunz » Tue Feb 13, 2018 11:48 am

Thanks to Shannon I gathered the courage to vinyl side my old 1930'ish house. The house is not insulated, despite the arguments online, I have decided to have cellulose blown in. On the exterior I have what I would assume to be wood clapboard in great shape, other than the paint job. From what I gathered from youtube, vinyl sidng needs to be nailed to a flat surface, and clapboard is not flat. So I figuered I need to reluctantly install a foam rigid board like everyone is doing online. I say reluctantly because I was trying not to beef out my house so much that when I install replacement windows, they will end up being sunk in the depth of the foam board plus the vinyl siding (they are currently flush to the clapboard). My question is, if I tack on foam board over the clapboard, there will be triangular gaps between the clapboard and the foam board. Will that space between the clapboard and foam board affect the barrier that I am attempting to create? I cannot find a video or a forum that discusses the matter, it's as if I am addressing the elephant in the room that everyone is attempting to ignore.


Clarence
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Re: How to install foam board over clapboard?

Post by Clarence » Tue Feb 13, 2018 1:20 pm

Make a positive profile of the clap board siding and take it to a foam cutting shop they can cut the shape so that when installed there is solid foam board matching the clap board.

TonyGunz
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Re: How to install foam board over clapboard?

Post by TonyGunz » Tue Feb 13, 2018 3:12 pm

Are you pulling my leg..? I have never heard of a foam cutting shop and if they did exist, im sure they would only service foam manufactueres and not an average doityourselfer like me.

Clarence
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Re: How to install foam board over clapboard?

Post by Clarence » Tue Feb 13, 2018 3:20 pm

No i am not pulling your LEG.
Check with any EIFS installer ask them where they get the shapes cut.
I have had very many shapes cut a hot wire is used to cut foam ALSO they use a laser to cut it very cheap to have it done. I also had my own hot wire machine, you can build one very easy. Check out EPS shapes on the internet see what you get

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Shannon
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Re: How to install foam board over clapboard?

Post by Shannon » Tue Feb 13, 2018 8:24 pm

Clarence wrote:
Tue Feb 13, 2018 1:20 pm
Make a positive profile of the clap board siding and take it to a foam cutting shop they can cut the shape so that when installed there is solid foam board matching the clap board.
I have never seen this or heard of this being done, sounds like a huge PITA and costly.
I personally would pull off the siding and install the foam over the wood sheeting myself . I have seen guys even install right over that old clap board but I don't like covering over old layers that do not need to be there.
What style of windows do you currently have? Can you post a picture?How thick of foam are you installing?
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Clarence
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Re: How to install foam board over clapboard?

Post by Clarence » Tue Feb 13, 2018 9:58 pm

NO PITA at all say you want the foam 1&1/2 inch thick give the profile to the supplier state the size of the sheets required say you want 1.5" X 4' X 8' sheets. They will load a 2' X 4' X 8' block in the cutting machine set the required thickness and cut 15 sheets total time 5 min. cost about $ 125.00.
Now you can cover 32 Sq/Ft at a time and have a smooth surface to install your siding over. WHY don't you look at some of the detail shapes that have been cut and are being cut from EPS board. I also have had a negative profile cut and used to pour plaster into than remove the EPS. Which would product the positive shape required i have used this method for 3 D capital tops works great.

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Shannon
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Re: How to install foam board over clapboard?

Post by Shannon » Wed Feb 14, 2018 4:47 pm

Clarence wrote:
Tue Feb 13, 2018 9:58 pm
NO PITA at all say you want the foam 1&1/2 inch thick give the profile to the supplier state the size of the sheets required say you want 1.5" X 4' X 8' sheets. They will load a 2' X 4' X 8' block in the cutting machine set the required thickness and cut 15 sheets total time 5 min. cost about $ 125.00.
Now you can cover 32 Sq/Ft at a time and have a smooth surface to install your siding over. WHY don't you look at some of the detail shapes that have been cut and are being cut from EPS board. I also have had a negative profile cut and used to pour plaster into than remove the EPS. Which would product the positive shape required i have used this method for 3 D capital tops works great.
Sounds great, I will guarantee there is no one in my area that does that but it would be handy in many cases.So average 1200 sq.ft bungalow would be maybe 35-40 sheets would be about 300$ extra? You can't rip the clapboard off for that and haul it away thats for sure. I guess in a perfect world if the clap board was all perfectly installed exactly like the profile you provided it would work.Not sure I would take the chance but it is an interesting option.
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Twolfy
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Re: How to install foam board over clapboard?

Post by Twolfy » Fri Feb 16, 2018 7:41 pm

I'm new here but have been learning from Shannon's videos for about a year now. Tony, I understand your concern with the windows being far inset after installing foam board and then vinyl siding. I had the same concern back in 2001 when I installed a 3/4" or 1" foam board (can't remember exactly) over T111 rough sawn wood siding and then put up vinyl siding. It looks nice though. If I were to do it again now I would remove the rough sawn board and go with a 2" foam board, tape it and then vinyl side it. Not sure about if house wrap would be needed. I will defer to someone here more knowledgeable than a DIY'er like myself. As far as putting rigid foam board over cladding I wouldn't be concerned, unless I'm missing something here, with the ridges as the foam board is "rigid" and will sit up on top of ridges in your clap board. Occasionally you might need a thin furring strip if board ends right on the indent but you could prevent this by measuring out first. Good luck on your project!
Hope to learn a lot more here from other members.
Tom

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Shannon
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Re: How to install foam board over clapboard?

Post by Shannon » Fri Feb 16, 2018 10:33 pm

As far as the windows being set in when adding foam and siding I have dealt with this two different ways just last year. (should have done a video for sure but the timing did not work for doing them)
In house #1 I was adding 2" foam and the windows were 3 years old. And they had reno brickmolds. So I ripped 2x4s to 3" wide and placed them on edge around the windows before the foam and screwed them to the walls. I then install white pre-bent metal covering the 2x4s so the entire finished product was maintenance free. There was a bead of caulk then between the metal and window frame. the foam butted tight to the other side and the house wrap went on and siding over that.
In house #2 I had 15 yr old windows with nail fins. I was installing 2" foam again. I took a different approach because of the nail fin needing to be exposable in the future if windows needed changing. I installed the foam and house wrap 7/8" shy of the window frames and then built a "L" shaped finished trim that would fit around the windows built from a combination of a fiber board trim and PVC trim.The PVC would slip in between the foam and the window frame where I had left the gap and make up the difference in thickness to hide the foam insulation edges because they stuck out further then the window. The fiber board trim was nailed onto those PVC strips and laid over the foam board . The siding J channel then butt to that. I will post a few picture of both.
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