Glueing wood to plaster

[Martin Bonner]

I am building some cupboards in our new bathroom. The walls are now made of soft wood-fibre insulation, so it is hard/impossible to screw any fixings to them (the fixings will just pull out). On the other hand, if I glue a sheet of wood to the wall, that will spread the load over a wide enough area that all should be well.

The walls are not completely flat, so any glue will need to be at least slightly gap-filling. I have had not had good experience with no-more-nails (skirting boards usually fall off). The obvious answer appears to be foaming polyurethane glue (manufacturers tend to claim that will fasten most things), but I have a pot of cascamite, and I wondered if that would work.

What does the panel think?

[Ret.]

I would have thought 'NoMoreNails' or one of its competitor products would be ideal. I've just bought some B&Q equivalent and it specifically refers to use for fixing skirting boards, battens, etc to walls. Having used similar stuff in the past I can vouch for the strength of adhesion.

[fred]

In article , Martin Bonner writes

Made of soft wood-fibre insulation or filled with same? What provides the finished surface? Plasterboard? Low density fibreboard? Any studs underneath?

The risk of gluing to any surface in a bathroom is moisture ingress and detachment of the surface layer that you have bonded to, resulting in the mounted item falling off and landing on someone's head.

Without more info on the substrate, I'd say bad idea.

[Martin Bonner]

The surface ~10mm is painted hydraulic lime plaster. There is then

100mm of Pavadentro (which is approximately very thick low-density fibreboard), and masonry behind that.

The floor will carry the weight, this is only to resist (eg) toddlers pulling themselves up by it.

The substrate doesn't really lend itself to screw fixing either ...

[fred]

Reet, yuk :-)

No paper on the surface though which was my worry, also no weight on it so other worries evaporate quickly too.

First thoughts are that you don't want anything too sticky. If you use foaming poly then I would expect the plaster to come off in a lump if you want the board(s) off. A no more nails type adhesive applied in the usual squiggles might be more appropriate, with that you might be able to probe behind to break the bond without too much damage to the plasterwork.

Perhaps some smaller 150mm sq pads glued on would suffice with screw fixings into those.