Plastering over wood?

[zenonithus]

Hey all, the door frame plaster pulled off to reveal the frame underneath. I know plaster doesnt stick too good to wood though if I pva it then put some bondig plaster should that do? Otherwise one trick I saw the plasterer do was to fix plasterboard to the wood and plaster over that, though not sure what the best solution is and I have no plasterboard :-\

 

[John D v2.0]

Yes wood will expand and contract, you would need some mesh, or plasterboard and tape the join between the two well. If you don't have the thickness to do any of that you can always cover it up with a moulding

 

[Gerrydelasel]

Won't it be covered with architrave?

 

[zenonithus]

yes it will be, though the architrave doesnt sit flush to the wood as the plaster is slightly raised over the wood on the other side. I have plaster board though it may be too thick, otherwise I have some Expanded Metal Mesh and Lath. Would I just nail this to the wood and plaster over that?

 

[zenonithus]

I screwed the plasterboard and the thickness wasnt too bad.

I will still need to fill the gap with bonding. Should I scrim tape where the bonding meets the plasterboard and skim over?

 

[zenonithus]

more exposed wood that needs plaster over, this time I nailed a bit of mesh to it for the plaster to grip to. Though not sure what to do about the gap? Should I just stuff it with bonding? Though not sure how deep it goes, or put some expandable foam in there and bonding over the top?

 

[roughcaster]

2 answers.
1,,, Scrim tape where the bonding meets the plasterboard.
2,,, Push some more wire lath into the gap, dampen down, then fill with bonding.

Another thing worth looking at. I don't know what type of nails you used for nailing the wire lath on with, but make sure they're galvanised otherwise they will rust, and might show through the finished plaster.

Before you fill up the gaps with plaster, give the area/s a good dampen down, and pva, then put on your bonding coat while the areas are still wet/tacky.

Another good tip about plastering onto areas wher there is "exposed timber".
Before fixing wire lath onto timber, I normally give the timber a coat of bitumin paint with a brush, and then fix on the mesh, It seals the timber and stops it from swelling up and cracking the plaster.

 

[zenonithus]

thanks for the advice roughcaster. I'm not sure if the nails are galvanized, good point. It will be a bit of a nightmare getting them out. Is there anything I can coat them with that will help with the rust? Otherwise might have to keep painting over the plaster.

with putting mesh in the gap do you mean just stuff it in so it holds into place? I cant fix it to the masonry above as its solid brick and tricky to nail to the top of wood. Also speaking of the wood should I give it a coating of pva even with the mesh on it? Cheers

 

[roughcaster]

With the rusty nails, just use a q tip and dip it into some "oil based paint", and dab it onto the old nail heads. With the gap, just "jam the wire lath in", it'll never budge. Just before you put the plaster in, spray some water into the hole, then pack in the plaster. The "jammed in wire mesh" will hold the plaster perfectly.
Regarding the wood, just dab it with the oil based paint, let it dry, THEN put on the pva, and plaster onto it right away,, no problem at all.

 

[zenonithus]

Great, will get some oil based paint tomorrow, cheers. Looking at the nails they have that faint rainbow shine to them so its possible they are galvanized

One thing I did which I wasn't sure of was apply the pva to the areas where chunks of sand cement crumbled off, though I let it set for 6 hours before applying the bonding as I had to pop out. Do you think this will be ok?

Also I will fill the gaps between the wall and ceiling with bonding, though is it wise to put scrim mesh tape around the entire edge of the ceiling/wall before skimming to prevent further cracking?