Gyprocking over a brick wall

[Scoutegg]

I'm a handyman, not a plasterer, but have done my share of bits and pieces.

I have been asked to plaster over a besa block wall (inside - bedroom) as the owners find it an eyesore. The wall is very flat and should cover very well, and is also painted.

Should I rely on adhesive alone? Obviously I have no timber to screw or nail into. Is stud adhesive good for sticking to paint or would a construction adhesive be better? Should I treat/clean/etch paint first?

I know you don't use glue on joins so if the gyprock is glued close to the edge, will it be cool to plaster and tape the joins without a mechanical fixture (ie: nails/screws)?

The wall is very solid and stable, so movement won't be an issue. I'm mainly concerned with the sticking bit.

Any advice?

[rod@plasterbrok]

You either have to do one of 2 things.

1st method is to clean off the paint at 450mm x 450mm intervals including along the join the wall and ceiling lines. Then use cornice adhesive to fix the board. http://www.how2plaster.com/stickonplaster.html this will give you the right idea.

2nd method is to fix either timber or metal battens to the brick and then mechanically attach the plasterboard to the battens using stud adhesive and nails/screws.

stud adhesive and construction adhesive both have pitfalls in their use in sticking to brick. Just don't have time to go into them all right now.

Cheers

Rod

[Make it work]

A few things come to mind here.

1. Is this the inside of an external wall? If not, no problem but if so, does the wall need to be either insulated or moisture proofed before you sheet it, you won't want damp or condensation problems?

2. Is the paint well bonded to the block wall? Any adhesive you use will only be as good as the bond of the paint to the block and moisture may affect this too.

3. I would use a fastener as well as an adhesive, something like this (http://www.powers.com.au/products/focus.aspx?bgid=36) will work, it is easy to use and comes with the correct size drill bit in each box of 100.

I used them for a similar application when I sheeted above & around 2 fireplaces a few years ago and they are still perfect.

Hope that helps...

[rod@plasterbrok]

The only problem I can see with that method it that while drilling the hole into the masonary through the plasterboard you would weaken the plasterboard where the screw should grab and the heads could pull through the board.

Also brick work is notorious for being bowed out of plumb etc. That for the average job, using these screws not only time consuming, compared to using cornice adhesive, but you would not have the straightening ability.

Mind, these screws with a suitable adhesive could work ok for a small job such as your fire place. My preference still is cornice or masonary adhesive then battens. These are proven systems that allow you to straighten the wall etc, if required.

Scoutegg says the wall is in a bedroom so moisture etc, would not be a problem.

Cheers Rod

[Scoutegg]

Thank you gentlemen,

I would rather avoid the batons if possible as this will shrink the room (it's pretty small already) even though it would only be an inch or so. I dismissed that idea when I first saw it. I have done that on another job though and it is the best option. The wall is surprisingly flat. Some bricky must be very proud of themselves.

I think the cornice cement will work after I've ground the paint off for glue points. Good idea.

I've used those Tapper fasteners before and they are great too. Thanks for the suggestion. I agree though, that drilling through the gyprock could create too much damage at that point.

So... thank you very much for your suggestions and advice, I look forward to picking your brains again.

Scoutegg.

[Make it work]

I agree that battens are the best way to go but I thought that seeing as the wall is described as very flat I discounted the need for a lot of correction.

I can't see how drilling 4mm holes in the besser blocks throught the gyprock would cause much damage to the sheets unless you used a huge rotary hammer.

If it were my job I would use the adhesive and hold the sheets up with a few screws till the adhesive of choice was strong enough. The fewer screws the fewer heads to fill.

If you do grind the wall to bare the blocks, be prepared for the clouds of dust it makes and make sure the adhesive is not applied to a film of dust, glue don't stick to dust real good.

[familyguy]

I built on a room about 20yrs ago with stud walls clad in fiber cement and gyprocked on the inside. One of the inside walls was an existing external besser brick painted wall. I have to admit knew almost nothing about building and ended up over engineering it. I was stumped when it came to that painted besser brick wall not knowing how to tackle it (no forums like this back then). I ended up glueing the gyprock to the wall with stud adhesive, 20 yrs down the track it has'nt moved. Obviously the paint had ahered well to the besser blocks which in turn were stable.

These days I might be tempted to do the same thing again if the job was myself, but if it was for a customer and my reputation was at stake I would take Rod's advice and use timber battens screwed to the bricks, I believe this is a safer way to go. In the years since the room was built I've seen quite a few instances where construction adhesive has come unstuck.