masonry screws or adheasive?

[grodenhiATgmailDOTcom]

I have a sunroom/mudroom in my house that is built on slab that rises about 6-8 inches above ground. Underneath the doorway going to the outside there was a plank of wood (then covered with vinyl to match the siding) that covers the slab under the doorway (kind of like a faceplate). This piece of wood has somehow become loose where it falls off periodically. Looking at the plank it looks as though it was never permanently attached, just sort of wedged in. I'd like to come up with a more permanent solution. I'm thikning one of two options:

1.) Construction Adheasive (Liquid Nails.. etc). This plank sits under the lip of the thresold and does not get stepped on. Would this work for adhearing wood to cement? Would it be a strong bond?

2.) Srewing the board to the slab using masonry screws. Now comes the dumb question... If I go this route do I simply buy masonry screws and drive them into the slab just like I would a normal screw into wood, or do I need to predrill first using a masonry bit? I can take the vinyl off the plank to do the work (so no screw heads would be visable).

Is there a better solution than either of these?

[bremen68]

I'd go with the masonry screws. You'll want to drill your hole in the wood with a regular bit, then switch to a masonry bit to pre-drill for the screws in the cement.

I had a similar problem with a basement door... It hasn't moved since. I added a bead of clear silicone caulk across the front edge to help keep water out too...

[Edwin Pawlowski]

I vote for adhesive. The urethane stuff is incredibly strong. Easier than using any sort of screw or anchor. Worst case scenario is that if it fails, you can still put the screws in later.

[John Gilmer]

Amen!

Old concrete doesn't want to "drill" right and, often, you end up with oversized holes. Even if he does drill, the belt and suspenders with the screws and urethane glue together will keep things in place indefinitely. That type of glue expands while it cures (and it cures by reacting with the water in the environment). Thus, it's important to have a good amount of clamping pressure on the joint.

I had some problems with carpet nail strips on a concrete floor. The original concrete nails weren't put in right as all the nail did was blast a crater in the concrete. The glue "fixed" the nail the locked the nail strip in place.

[grodenhiATgmailDOTcom]

I'm starting to lean more and more towards the glue side of things (at least for round 1). Hopefully this holds, this board doesn't take any abuse (it simply is a faceplate below the door threshold facing outward). There's really no way for me to clamp it though, so my thought is to lean a heavy patio paver up against it while the glue cures for 24/48 hours). I'll just have to find a warm day as this is in New England and nights are now getting into the upper 30's.

John Gilmer wrote:

[John Gilmer]

Of course! You "clamp" something to the ground with a BRICK!

[yorick.phoenix]

Alternatively screws give you more options for the future should you want to change what you have for something else without having to deal with "unglueing" and breathing the glue while it cures.

Yorick

[grodenhiATgmailDOTcom]

This is not on the ground (or floor) it's basically a faceplace for the "wall" below the doorway on the outside. Basically the doorway is about 4-6 inches above ground outside (as the doorway sits on top of the slab). This covers the exposed slab underneath the doorway (basically it's siding below the door).

John Gilmer wrote:

[John Gilmer]

That's a lot more difficult: keeping pressure on verticle surface. I'd say you are stick with anchors if you want ot be sure. In old concrete you often end up drilling an oversized hole because of a mix of "hard stuff" and "soft stuff."

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