foamie wall to floor attachment options ?

[lthomas987]

This is what I did and was trying to describe earlier. After the wall was glued up and dry I unscrewed the offcuts and reversed them. I did run drywall screws both into my wall foam and into my floor. But I wasn't worried because I hadn't finished sealing either of them, obviously.

[rustytoolss]

This is what I did and was trying to describe earlier. After the wall was glued up and dry I unscrewed the offcuts and reversed them. I did run drywall screws both into my wall foam and into my floor. But I wasn't worried because I hadn't finished sealing either of them, obviously.
So drywall screws will thread into the xps foam and hold for some uses ? Not to sound stupid, I know that expecting that using dry wall screws into foam would not support any weight. But they can be used to hold things together (no load usage).

[lthomas987]

So drywall screws will thread into the xps foam and hold for some uses ? Not to sound stupid, I know that expecting that using dry wall screws into foam would not support any weight. But they can be used to hold things together (no load usage).

Um. They will thread. But they won't hold really. For tacking together while glue sets they are fine. I used the to help hold my roof while it dried too. Like bamboo skewers. But slightly more clamping power if you gave them a cardboard washer. And don't over tighten them so they strip out.

[rustytoolss]

So drywall screws will thread into the xps foam and hold for some uses ? Not to sound stupid, I know that expecting that using dry wall screws into foam would not support any weight. But they can be used to hold things together (no load usage).

Um. They will thread. But they won't hold really. For tacking together while glue sets they are fine. I used the to help hold my roof while it dried too. Like bamboo skewers. But slightly more clamping power if you gave them a cardboard washer. And don't over tighten them so they strip out.

Need some clearafaction " I used the(??) to help hold my roof while it dried " ???????????

[lthomas987]

Sorry. That was terribly unclear. I used drywall screws driven through the roof into the sides while the glue dried on my wall roof attachment.


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[rustytoolss]

[KCStudly]

I used 2x2 cedar along the base of my foam wall cores. This did several things for me: (1) it held the bottoms of the walls dead straight during construction and assembly; (2) it provided a hard protective edge that allowed me to handle and drag the walls around, sliding them along the floor of the shop at times w/o having to worry about damaging the relatively delicate foam; (3) it gave me a hard reference edge to work to; (4) it made for a positive screwed joint when attaching the walls to floor with PLP buy screwing up thru predrilled holes; no issues with glue expanding the joint, screws stripping out, or awkward strapping; and (5) it gave me hard blocking along the base of the walls to screw the surface mount vinyl wire chase product that I used to keep most of my electrical system accessible, yet securely contained.

I would not want a 2x2 extending into the cabin as it would if used as a cleat; 1-1/2 thk walls are thick enough as it is. The real reinforcement comes from wrapping the outer skin under.

[dancam]

KCstudly- any particular reason for using cedar?

The 2x2's give you something to screw cabinets and stuff to as well as all the benefits KC mentioned. However they do add weight.
I would reccomend pl premium if you havent considered it already. Drilling lots of holes into the foam and filling them with glue in addition to the glue along the whole joint provided the strongest bond for me. The glue filled holes in the foam really do the trick.


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[KCStudly]

KCstudly- any particular reason for using cedar?

Long straight grain; no knots; naturally rot resistant due to its high resin content; and very light weight.

I was less concerned about ultimate light weight, and more concerned about being able to build accurately using a combination of foamie and traditional methods. The wooden sill plates gave me a hard point allowing me to build and fully finish my wood inner skinned walls separately, while at the same time allowing for a no compromise screwed and glued joint with the floor. Made sure that the base of the wall was dead straight with no issues when the floor got pulled to it.

Drywall screws into foam just didn't seem like they would offer the same pull.

[rustytoolss]

Can I use the PL to glue the foam to the 2x2's and the plywood ?

[dancam]

Can I use the PL to glue the foam to the 2x2's and the plywood ?

Yes, i did my whole foamie with it. All the wood to foam and foam to foam joints. In my comment above when i talked about filling the holes with glue and putting it on the seams i meant the pl premium.
Look through some builds maybe of people who used it to see what they said. I cant remember who i saw post a detailed description of drilling the holes in the foam and filling them with glue, but its out there

[KCStudly]

I cant remember who i saw post a detailed description of drilling the holes in the foam and filling them with glue, but its out there

I'm pretty sure that rowerwet is the one who has been experimenting with "glue nails".

[Andrew Herrick]

You can use plastic roofing cap nails to screw the foam to a wooden cleat.

KCStudly, did you experience any splitting with the cedar?

[KCStudly]

...did you experience any splitting with the cedar?

None that I can recall, and none for sure at the floor to wall joints. I did do a dry fit; pilot drilled all of the screws with a countersinking pilot bit up thru from underneath; and then opened the holes thru the floor up for the shanks of the coated deck screws.

For the floor and bulkhead internal frames, door surrounds and door frames I mostly used plate (biscuit) joinery, but wherever I did screw I pilot drilled. Anywhere critical that I felt I might be doing multiple assembly/disassembly cycles during dry fits, specifically with the small #6 screws, after pulling the screw out I put a drop of CA glue in the hole and let that soak in to strengthen the "wooden threads". There weren't too many spots where I felt this was needed, but it is a good trick to know for soft woods.

[KCStudly]

One more thing that may or may not have made the wall to floor joint stronger and less prone to splitting the cedar; I staggered the row of screws. Rather than putting them all in a straight line down the center of my 2x2 sill board, I staggered every other screw in or out about 1/2 inch so as to broaden the footprint of the clamping effect and lengthen any potential interruption between individual wood fibers. IIRC I spaced the screws every 6 to 8 inches or so along the length of the wall; probably a little overkill but it made for a nice solid joint that pulled the PLP down nicely.