Adhesive advice

[Mark A]

Hi chaps,

I've almost finished preparing a floor prior to laying engineered oak by packing out with hardboard and overboarding with 12mm ply. The last piece of plywood will go down over a particularly bad area of subfloor which dips and rises too much to be easily packed out, so I'd like to use an adhesive which sets rock hard and can fill large gaps.

Any suggestions?

Cheers,
Mark

 

[NazNomad]

I'd get the floor as good as possible before laying the 12mm ply... using something like this - https://www.screwfix.com/p/no-nonsense- ... GwodhKYJnw

 

[Homers double]

Hi mark
I can highly recommend sikabond 54, I’ve recently laid a very large parquet floor which went through 3 rooms and a hallway, one room was about 15mm lower than the rest so I glued and screwed some ply down, the sikabond 54 filled all the unevenness and glued the ply to the original sub floor, we were able to get the floor very level prior to laying the parquet.
Harvey

 

[Mark A]

The problem with typing on a phone with numb hands (and an irritating burn on end of my typing finger - who'd have known a wood burner can be hot?) is that it soon gets frustrating, and so I say to myself "bugger it" and press submit without ensuring what I'd typed actually makes sense.

I should have clarified that the plywood I overboarded with is now acceptably flat (and almost level) as it's been packed up with four-and-a-half sheets worth of 10"x5" hardboard packers and I will be floating the engineered flooring on thick underlay. The last piece of plywood to go down is in front of a patio door and the old chipboard subfloor rests on the blocks between the joists, which are higher than the joists themselves. There's a crawlspace beneath this floor and I can see the joists haven't dropped; either they have shrunk when they dried out (over 1/2" than when installed?) or the ******* who did it in 1976 cocked up. Going by the standard of workmanship around the rest of the house I suspect the latter.

Anyway, to make the last piece of plywood lie flat I've planed and sanded a 12" wide bevel along the entire edge, which will need supporting with something which sets hard, fills large gaps and will adhere to chipboard, hardboard and plywood.

 

[Mark A]

Naz - too late for self leveller as all but one sheet of ply is already down.

Homer - how flexible is the adhesive you suggested? If there's any give I'd be concerned for the engineered boards above as the rest of the floor's solid.

 

[Mark A]

Picture of sloping section of floor and bevelled plywood.

 

[Jake]

I'd use no more nails type stuff - solvent one that sets hard like pinkgrip. Cheap too.

 

[Mark A]

I have a couple of old tubes of Gripfill here, but it takes a while to set and I was hoping to crack on with the floor tomorrow.

What about two-part wood filler or car body filler?

 

[Jake]

Sets a bit too fast for that area, quite brittle, not cheap in that quantity. Fast-set tile-on-wood adhesive?

 

[Jake]

Or pin some packers to the chip to hold the ply at the right level and in enough places to hopefully hold it up if it gets stood on accidentally, then gripfill. And pray.

 

[Mark A]

It's not a very big area and the packers fill up most of the gap (see cat for scale).

Would it matter if filler cracked as it'd be sandwiched tightly with screws once it had set.

 

[gaz44uk]

Would Gap Filler not do the job once dried it can be shaped to any size or area or would it compress underfoot ?.

 

[Geoff_S]

What about adhesive foam. It doesn't dry solid, but it will fill and pack the gaps.

By the way, what are you doing with my cat?

 

[Mark A]

Hi chaps,

All done. Initially packed it up with multiple pieces of damp course, and once it was level added dollops of wood filler to give extra support (found an old tin on a shelf in the shed) before screwing down. Feels solid enough.