# Protecting exposed internal oak ceiling joists



## RogerS (9 Oct 2008)

Two rooms. One with very old and bent oak joists and the other new straight green oak.

Problem - going to be plasterboarded in between and I want to protect the beams and minimise the amount of work after the plasterer has done his worst. Already done many rooms upstairs and the missus is getting a tad bit fed up cleaning down the beams after the event.

Taping up doesn't work but a fitter told me about some sort of spray on stuff (wax he thought) to put on the beams first so that plaster would come off easily and not stain.

Now, in my experience water (aka plastering) doesn't bode well for normal sort of briwax wax so is there anything better? What might they have used to spray on ?

Thanks


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## Woodfinish Man (15 Oct 2008)

This is a difficult one.

Something that may work and worth looking into is a product called Gramos Peelable Spray Coating. It is normally applied to metal spray booths and after it has attracted all the dust and vapour particles removed.

I see know reason why it shouldn't work on timber especially if you seal the wood first with a coat of Polyurethane Varnish Satin. 

Your best bet is to give Gramos a call although they will probably say no - I'd be getting a sample of their product and giving it a go.

Hope this helps in some way.


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## chipchaser (15 Oct 2008)

Hi Roger,

never used this myself but recall that a colleague used a latex coating to protect timber.

You might Google: "Peel-Guard" peelable liquid applied latex rubber protective coating.

The problem I anticipate arising is if your oak is unsealed/finished. The coating may be difficult to remove from open grain and pores etc.

Watercolour painters use clear or tinted latex masking fluid which they rub of with an eraser when not required. 

I have exposed reused timbers in one room of my house. I can't remember (20 years ago!) how I protected them whilst plastering between but they cleaned up without much trouble. I think I taped thin polythene sheet around them and then used a sharp thin blade to cut off the poly flush with the plaster. You can cut through any excess plaster blobs too.

Hope this helps

Graham


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## DangerousDave (15 Oct 2008)

Roger, what about simply using masking tape? When fitting new skirting I apply masking tape to the floor flush with the wall but a good bit wider than the board, fit the skirting, apply the finish then tear up the bit of masking tape thats showing beyond the skirting if you know what I mean. Could you do the same to the beams? i.e. apply enough tape width to cover the depth of the plaster board and skim coat(s) plus a bit more. Fit the plaster board, then when your plasterer is cutting in he's got that bit of masking tape to work to. When the skim coat has gone off, carefully score the tape with a stanley knife at the point where the plaster meets the beam and pull off the excess. If your worried about plaster splashing on the remaining exposed bits of the beam, simply cover with 300 gauge polythene etc.. and secure with tape. I find that the masking tape thats guaranteed to come off cleanly within 48 hrs still comes off with little or no residue after a couple of weeks  HTH


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## Skelp (15 Oct 2008)

Be aware, if you do opt for a brush-on liquid latex barrier, it may react with the tannin in the oak and cause staining. What ever solution you choose, I would recommend testing the whole process beforehand.

I've used the masking tape trick on the floor prior to fixing skirtings too. I ran a flexible blade along the skirting prior to painting it so the excess masking tape peeled away easily.

If you could accurately predict the thickness of the ceiling plaster, you could do a similar masking job. Perhaps you could wipe some Vaseline over the tape too to ease the excess tape from under the plaster when it's dry.


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## RogerS (16 Oct 2008)

Hi guys and many thanks for the suggestions.

I think that the masking tape might work for the new beams providing that I only apply it just before plastering. Because the house is unheated, tape is reluctant to stick to the beams. But as I type this I have just had a Eureka moment :idea: based on all the suggestions.

Here's the plan. 

The plasterboard is not yet up between the joists. Neither are the noggins that the plasterboard will go onto. So if I get some builders plastic sheet and pinch it between the noggin and the joist then fix the noggin to the joist, wrap the sheet around and under the joist and back up the other side where it will be fixed with another noggin then all I should have to do is cut the plastic sheet off at the plasterline after the plasterer has done his worst?

What do you reckon?


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## lurker (16 Oct 2008)

Can't you just "bandage" the joists with cling film and cut exceess away afterwards.


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## RogerS (16 Oct 2008)

Nice idea, Lurker, but I can't get to the top side easily.


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## DangerousDave (17 Oct 2008)

RogerS":3dth2z5w said:


> Hi guys and many thanks for the suggestions.
> 
> I think that the masking tape might work for the new beams providing that I only apply it just before plastering. Because the house is unheated, tape is reluctant to stick to the beams. But as I type this I have just had a Eureka moment :idea: based on all the suggestions.
> 
> ...



The plastic sheet would need to be very secure to the beam, any movement in it when cutting in/when plaster is going off/when you're removing the excess could ruin the finish. This then takes you back to the issue of using some form of adhesive to secure the plastic to the beam :? Dunno, it might work tho. It would mean the edge of the skim coat would be bonded to the plastic which in turn wouldn't be bonded to anything except where its held in place with the noggin. Sorry thats not much help to you Roger, but to get a clean plaster line it'll be important to think what the edge of the skim is bonding to.


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## MikeG. (18 Oct 2008)

Getting a clean plaster line alongside a green oak beam is completely unecessary, as the oak is going to shrink so much in the next 12 months or so that the gaps will be up to 12mm or so wide. You will inevitably be replastering or at least filling and redecorating, or putting cover mouldings up.

Actually, it is probably quicker and easier to remove the plaster overspill from the oak than it is to muck about with masking etc. Gypsum plaster doesn't stain oak (in the way that mortar does). It rubs off completely and easily with a wet cloth or sponge, leaving no hint that it was ever there. It really isn't an issue........my house is full of new oak, plastered between, and I have been involved in dozens of jobs like this over the years.....there really is no problem. Your plasterer should do most of the cleaning-off.

Completely different situation if cement mortar is involved, though.....that does weird things to oak.

Mike


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## CWatters (23 Oct 2008)

Beware masking tape. I used some that claimed to be long life. A week later I tried to remove it and it made a right mess. Had to try use all sorts of different solvents in an attempt to get the glue off.


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## RogerS (23 Oct 2008)

I agree, Mark, that new oak is not a problem...nice and straight..no woodworm..but old ancient oak is a different issue as the grain is much more open, worn, woodwormed..you name it..and plaster fills in all the cracks and is a nightmare to get rid of.


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