Hardiplank over foam board over OSB

[tjcanno]

Greetings all! I have been lurking for a while, getting ready to break ground on the garage at the end of the month. I am in North Georgia in the mountains.

I was thinking about putting OSB over the framing studs and then foam board over that and taping the foam board.

Then putting Hardiplank siding over the foam.

My siding contractor is concerned about putting hardi siding over the foam. He says it will move because it won't get secure through the foam.

Anyone have any experience with that?

I need to get back to him right away with a decision.

Thanks!

Jim

 

[sselander]

They do not mention installing over foam board, just solid sheathing and a vapor barrier.

Installation guidelines can be found here:

http://www.jameshardie.com/builder/support-installation.shtml

 

[deter]

for what reason do you want to put foam on top of the osb?

 

[tjcanno]

for what reason do you want to put foam on top of the osb?

Trying to get a base level of insulation outside, then insulate inside later. It is an idea I picked up on GJ. Maybe its not worth it.

 

[rockchucker]

If you do anything just put the Foam Board between the Studs on the inside of the Building or insulate normally.


There are a bunch of idiots here in Seattle that keep talking up installing Foam Board on top of the Sheeting on a Roof then installing the 3-Tab Composite Roofing OVER the Foam Board!!! Sorry but unless you have stuff anchored it will fail. Regardless of how it will fail...IT WILL FAIL!

I would highly suggest not trying to reinvent the Wheel. Use the tried and true methods that have been proven to work over a century. Not what has just come onto the market as a new idea. Any new idea needs to be tested for 50 years before it is proven.

OSB...Don't even get me started on OSB that is so widely used today. I will not use it. It has not been tested long enough because it has not been around long enough. Look at the homes built in the early 1900's. They are still standing only requiring normal maintenance. Even some homes built in the 70's and 80's and newer are already being torn down due to failure and inferior building products. Oh buuuuut it is to code....Yeah a big huge scam of a code requiring everything to be built using particular products that have not even been tested thoroughly.


If you really want to use the Foam Board on the outside then you will want to install it then go over the ENTIRE building with 1x2 or something similar every 12" or the width of your Siding so you have something to anchor the Hardi Plank to. I have done this on Concrete, Stucco and Block Homes to install Siding but it is well more of a PITA then it is worth for sure.


Just my 2¢ though.

 

[deter]

around here, 1/2" foam board (r2) costs about $.40/SF.... r13 faced batt costs about $.25/SF.

 

[tjcanno]

OK, thanks. I might drop it. It is just a garage, after all. I am not living in it (yet).

 

[rockchucker]

You may be after the project is over and the wife sees what the Contractor tacked on to the bill for your custom Foam Board! lol

I would bag the Foam Board for sure. You will get much better insulation for your money using good old Fiberglass Faced Rolls of Insulation on the interior of the building.

 

[HunterWare]

Check out Zip Systems R-Sheathing. I'm dried in with my new barn/garage using that and the whole experience has been great. The price really wasn't bad when you realize you bought the OSB and foam and TyVek all at once, and then put them up almost as easily as just putting up the OSB alone (labor time isn't free). The place is incredibly tight too. The R-Sheathing also puts the foam under the (coated) OSB, so any siding is just done conventionally.

I know a couple others here have used it too, and I haven't heard anything but praise from people who have it.

 

[tjcanno]

My siding guy actually recommended the Zip board today. I will look at it. Thanks for the replies, guys!

 

[Spudland_Dave]

There are a bunch of idiots here in Seattle that keep talking up installing Foam Board on top of the Sheeting on a Roof then installing the 3-Tab Composite Roofing OVER the Foam Board!!! Sorry but unless you have stuff anchored it will fail. Regardless of how it will fail...IT WILL FAIL!

Those idiots aren't confined to Seattle...some of them here in Maine too. I will disagree with you on the new products thing though , I know what your saying, but I wouldn't blame the new products. I will blame crappy workmanship and cost cutting.

For years we've been told you NEED to have a vapor barrier on the outside...ie Typar/Tyvek...which I believe. Now some of these idiots are putting foam board? Last time I checked foam wasn't permeable. So common sense would dictate that the moisture could collect between the foam and your sheathing. I don't care if your using RockChucker's old fashioned boards or new ZIP sheathing (Love the ZIP system BTW), it will rot right there if it cant breathe.

A buddy of mine is getting ready to build a house and contemplated doing it because one of his buddies did it...my response was if you want more R value in your walls, frame with 2x8's and forget the foam.

 

[rburke65]

I think Tyvek is a water barrier. It will allow water vapor to pass but restrict air infiltration in a build.

 

[tjcanno]

I decided Zip board was too costly for what you got. I am just doing OSB with Tyvek, then Hardi siding and putting all the insulation inside the 2x6 walls.

Thanks for all your input.