Vinyl Siding With Foam Insulation

This home has quite a few ‘soft spots’ in the siding. All I know is that it’s newer vinyl siding with foam attached (not foam board insulation). Any ideas? Is that a poor install?

Secondly, the panels overlap each other by a good two inches but you’ll notice in the pic they are not exactly flush with each other. Install issue?




The siding is designed to overlap like that. That way as it expands and contracts there won’t be any gaps.

As for it not being flush, it is also designed to be “hung” not nailed securly. The nails are intentionally left a little loose so when it does expand and contract it won’t bind on the nails and buckle.

As for the soft spots, that’s problably where the foam insulation under it, was either removed or fell out prior to installation. If it’s only in one or two spots, I’d just note it and move on. If it’s “everywhere” then then that might be a bigger issue. You’ll need to decide that.

Not an answer so much as a question Erol.
I hope they used sheating such as osb .
They should also have other insulation behind the moisture barrier as I read up on it the insulation behind the siding is most likely no more than R4.
Wonder also why the seams line up that way as they are usually staggered

Mark with that much give could they unlock?
Also looking at the pic more I see the panels may be wider than usual.
Got a link for this stuff?

Thanks Mark,

We’ll find out pretty soon when he has a contractor come out and remove a section. I observed a small area of ice build up on the inside wall of the living room. I’m concerned that he may not have a vapor barrier. Thermal scan showed only a small area of missing insulation. I know it’s not focused…

Cold Air Near Outlet.jpg

I see what you are saying about lining up now. I’m thinking they are double wide panels but I’m not sure.

As for “give”, we’re not talking a lot. But you should be able to “slide” the panels back and forth a little (with some effort). If you can’t, then the nails are too tight. And no, they don’t unlock unless there are very high winds, and then you’ve got other issues. Of course with the picture, I can’t tell how “loose” they are. The nail head should be nailed in far enough that the underside is holding the siding next to the sheeting without pinching or dimpling.

No web site, just installation instructions from the local big box store, when I was considering it for my own home.

Hi Bob,

Just noticed your post. Yes, I have a big concern what’s behind this siding. Especially since the client believes there isn’t a moisture barrier and I suspect there isn’t a vapor barrier. :shock:

Erol, They have two but joints one on top of the other, they should be staggered and this looks like double two sidings with a full back unfused and installed in the field.

I believe it looks as shown like in this link.

Hope this helps.

Marcel :slight_smile: :slight_smile:

Thank you, Marcel. :cool:

good link

Marcel knows his stuff. :cool:

Erol, There is a new siding on the market that has pre-formed foam backer that has to be installed behind the siding, looks to me like some of the foam backing is missing. Marcel is also correct about the butt joints being stacked on top of each other, should be a 2 foot stagger for each course of siding.

I’ll try to find a link for this new siding, it actually has a decent R value but very expensive.

Found it,

Thanks Pete. Yes it does have the foam backing. I have a concern with installing this siding over a 20 year old frame that never had house wrap.

I would be too, vinyl siding is not a water tight product and neither is the foam that is installed under it.

Every building needs a vapor/moisture barrier under the siding, no matter what type of siding is used. In some cases, especially in coastal area’s a secondary barrier is wise to use such as felt paper.

Expanded foam insulation itself holds water and essentially becomes a resevoir for water bypassing the siding. On sunny sides of the house, this water heats, turns to vapour and can move though the permeable sheathing membrane into the wall system due to higher vapour pressures. I have seen the sheathing and sometimes structural elements rotted. In our area, the rain screen principle has been added to the provincial building codes in 2004 to allow water to drain and not be held in and behind porous sidings.