Fasteners for Vinyl over Thick Foam
KarlKarlofson
| Posted in General Questions on
My family is building a new home. The plan is to do 2″ of PolyIso as a continuous thermal break/control layer over the sheathing. We intend to use vinyl siding. I understand that the fasteners for the siding need to penetrate the a nailable surface by 1-1/2″, so we will nee at least a 3-1/2″ fastener. What are the best and most cost effective options? Typically Vinyl siding is fastened using roofing nails, but there appears to be no=such-thing as a 3-1/2 in roofing nail. So what to do? What ARE our best options to attach vinyl over 2″ rigid foam?
Thanks,
Chris
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Replies
While vinyl siding manufacturers recommend no more than 1" foam under their products, It seems reasonable to use 2" if the siding is fastened to framing as it seems you intend to do if you are concerned with a 1 1/2 nail penetration. However, the siding wants to be fastened 16" on center. Modern houses typically have 24" on center exterior framing. If you only want to attach the siding to the sheathing (as is almost all vinyl) 3" nails will penetrate through up to 3/4" sheathing.
I recently did a similar project, only I was using insulated vinyl. The extra 1/2" thickness dictated 3 1/2" roofing nails. I got them from Best Materials (part # EGR312). Expect to spend more for shipping than the nails.
Half on my project was sheathed with 3/8 plywood the rest with shiplap. I To reinforce the thin sheathing and air seal the whole thing I added a layer of Zip taped 3/8 plywood. This gave me a minimum 3/4" for the nails to penetrate. Perhaps you might consider upping the sheathing to 5/8" plywood to provide extra support for the cantilevered siding.
https://www.amazon.com/GRK-CAB8318B-Cabinet-8-Inch-Screws/dp/B003VCBERM/ref=sr_1_4?gclid=CjwKCAjwopWSBhB6EiwAjxmqDagW_4IZ_b_cQLbQEhYTIA-8wYcG4pcSBuKijZUFK1gxudBG6IzFQhoCsWkQAvD_BwE&hvadid=410020103700&hvdev=t&hvlocphy=9001858&hvnetw=g&hvqmt=e&hvrand=9148187657147315078&hvtargid=kwd-12873345244&hydadcr=954_1012856229&keywords=grk%2Bcabinet%2Bscrews&qid=1648769026&sr=8-4&th=1
I echo what he said above.
I have used GRK cabinet screws with great success.