Fixing Plasterboard to a brick wall

[Strungout]

Hi all.

I am on holidays and have started renovating part of the house.

I have an open brick fire place which all the render has started to fall off.

Instead of re- rendering the brickwork I wanted to fix some plasterboard to it but I don't have the room to batten it out.

The brick work is a little rough but its not too bad.

Can I stick the board straight to the bricks and what preperation will the require?

Thanks in advance.

[kenmil]

Are you talking about the fireplace surround or the fireplace itself ? I presume you are not going to use it as a fireplace anymore:confused:

[Strungout]

Sorry,I should have made it a bit clearer.

Its actually the brick chimney which forms part of the internal wall

We will probably put a Gas Log unit in there.

[journeyman Mick]

Gyprock is not fire/flame proof. If you want to stick it to brickwork you can do so with a combination of wallboard adhesive (made by the various plasterboard maufacturers and comes in blue, green or pink depending on brand), cornice cement and mickey pins. Put walnut sized dollops of the adhesive on the wall at about 400mm centres and put about 6-8 generous dollops of cornice cement per 2.4 x 1.2 sheet on the wall as well. The suction of the cornice cement will hold the sheet to the wall while the adhesive goes off, plus the cornice cement sticks like sh*t to a blanket when it goes off. If neccesary on the next course of sheets up the wall, or on small odd size bits you can hold the sheets in place while the adhesive sets with "mickey pins" - small masonry nails. No need to drive them home, just tap them in far enough to hold the sheet. Once all the glue has gone off either drive them below the sheets surface or pull them out, either way you will need to flush (plaster) the sheet at that point. If the wall is irregular you can use a straight edge to glue packers in place before hand.

If it is the actual fireplace you are talking about you will need to render it with fire proof cement or fireclay. Normal cement will disintegrate with the heat, as will the mortar holding your fire place together if it was made with standard cement and protected by the render.

Mick

[Strungout]

Thanks Mick,

Yes, its not actually the fireplace but the brick chimney that forms the internal wall of the room.

Would I have to do anything to the brick work before putting the glue on. IE primer of some sort.(Cemstick + Water) or just give them a wipe over to remove any loose stuff.

The old place is about 95 years old and I am trying to restore it to its "allmost" original style. WHAT A JOB!!!!!

[journeyman Mick]

As long as the surface of the bricks is sound, no dust etc. primer shouldn't be needed, but as you've got flaky render it may be. I'm a bit concerned about the impact that heat might have on both the adhesive and the cornice cement. You may need to contact the technical department of the wallboard manufacturer. Cornice cement is basically plaster of paris and I know that when this is heated enough it basically explodes as the chemically bonded water turns to steam. The wallboard adhesive is (I think) acrylic based and may melt or break down on a chimney mantle. I find it's always better to be pessimistic about all the problems that might happen before you start a job, rather than being unpleasantly surprised afterwards!

Mick

[Strungout]

Hey Mick,

Just to let you know that I spoke to CSR today and they advised me not to use it due to the heat factor (as you said).

Looks like I go and learn how to plaster now!

Thanks for your help

Greg

[econ]

you could use cement sheet but:

Its more expensive

its more difficult/dusty to cut

best fixed with a few dynabolts

its strong , wont dent easily and wont crack

[Zed]

Hi,

Sounds like you're going to an awful lot of trouble ? Wouldn't it be easier just to render it ? 95 yrs and only just falling out... speaks volumes.

I would get my angle grinder, score horizontal & vertical cross hatch patterns in nice deep wide trenches and re-render the surface.

Bob's yer uncle!

Cheers

Zed

[chocworks]

Hi,

I'm a first timer on this site and have found the info very helpful. Further to the assistance given regarding applying plasterboard to a brick wall - what is the impact of the bricks being painted. Can the plasterboard be applied straight onto a painted brick surface or should the bricks be stripped and cleaned?

Thanks.

[glenn k]

When I had an old solid brick house I went around tapping the walls and chimneys when it sounded hollow I broke it out with a hammer. Then rendered with 8\1\1 sand\cement \lime may have been 6\1\1 let it go off a bit scraped it level to the rest of the wall let it set more then rubbed with a broom to remove grit. then put hard plaster over the top and polished with a float it is easy with practice. I did one a few years ago and found it a lot harder than when I was in practice 20 years ago.
Good Luck