Wainscot

[Tim Lamb]

I am about to glue some grooved MDF sheet to an emulshed plaster board wall.

6mm primed stuff from Wickes. Any gotchas I should be aware of?

[The Natural Philosopher]

It probly will tear the emulsion off. shove some screws through it as well/instead.

Fill the holes with filler

[alan_m]

+1 for the emulsion being the weakest link

If the wall isn't perfectly flat the the glue may not stop the mdf from straightening out and leaving gaps between the MDF and wall. I have a nail gun and I would use that as well as glue/no=more nails etc.

[Tim Lamb]

OK. Not planning to put any load on it but there is always cleaning lady!

>

[newshound]

While emulsion can blister and flake locally, with a reasonable area of contact and a sound coat on a good surface (like plasterboard) you'd probably get away with it. I wouldn't try for a picture rail that I was planning to use as such.

[Tim Lamb]

OK. The studs are probably at 600 centres. Currently acclimatising the MDF to indoor temperatures.

>

[nothanks]

I would fix (screw) thin battens to the wall and then fix the MDF to the battens (small nail gun). This overcomes the ups and downs of plaster, plus means the MDF can be removed in the future without having to re-plaster the walls.

[Tim Lamb]

I'm rather hoping this will see me out! Sadly the skirting board is tapered at the top. The 6mm is just about flush and accepted by management. The wall is factory assembled timber frame and looks flat. Probably only two coats of emulsion since 1995.

[Andy Burns]

Batten spacing will need to be quite close to avoid 6mm MDF deflecting rather easily ...

[Andy Burns]

I'd use a low expansion foam, have had good success using it to line plasterboard onto painted, unplastered brick walls in a porch, braced against opposite wall using spreader clamps and random bits of 4x2

[Tim Lamb]

The bracing while setting issue has been exercising my mind. The last big sheets I glued up were braced using flexible battens from the opposite wall. Not practical here although the island unit would work for part of it. Current thinking is to combine TNPs fixing screws with some temporary horizontal roofing batten. Checking for *square* against door frame, I found the MDF slightly bowed towards the painted side:-( With 6 sheets to glue, fit, attach battens without anything falling off the wall is going to take more pairs of hands than I have! Oh well. Preparation is under way. First locate the uprights...

[Brian Gaff (Sofa]

Yes even a slight warp or out of trueness will not allow the glue to hold on paint. I've been there. Screws are to be preferred or a lot of nails. Brian

[Andrew]

MOdern vinyl matt is rubbish so you might even be able to wash it off where the glue needs to stick.

Or just stick it on with no-nails in dot and dab mode but abrade the paint where the glue is to be applied then just push the mdf panels on to it and hold in place for a short while. If they are above floor level then some temporary mechanical support might be required.

What are you going to prime the MDF with though ?. Water-based primers might make the surface rough. Finding solvent-based wood primers seems to be more difficult these days. Wilco used to do one but I was in my local one yesterday and couldn't find it.

Andrew

[Tim Lamb]

In message <su8gpq$1ntn$ [e-mail]>, Andrew [e-mail] writes

The Wickes stuff is already primed. I'm going with the advice on the glue (polymer) instant grab. Strip all round 50mm in from the edge and then parallel strips to fill in. Backed up with some strategic screws. The stud spacing is 600. Sadly the board width is 605. With 2 lots of 6 panels to fit, I am going to find the vertical joints moving off the studs. The edges are grooved to match before trimming is suggested:-) Now to find the noggins.