Perforated paper tape vs fibreglass tape for plasterboard jointing

[princhester]

The title says it all really: should I use perforated paper tape or fibreglass tape for plasterboard jointing? Boral says use the former, and definitely don't use the latter. CSR recommends the latter. Is there some sort of commercial ulterior motive here, or is there a problem with one or the other?

[echnidna]

fibreglass tape is much easier for a novice to use!!

[routermaniac]

along similar lines, I have a number of cracks in the plaster... what is the best way to use the tape? Do I line it up and just paint over it? does it need to be glued?


Please help :confused:

[princhester]

fibreglass tape is much easier for a novice to use!!

And I think that's what I'll use. But satisfy my curiosity: if fibreglass is easier to use, and if (as I would assume) fibreglass would be stronger than paper, why are Boral so against it? Anyone know what the alleged problem is supposed to be?

[echnidna]

along similar lines, I have a number of cracks in the plaster... what is the best way to use the tape? Do I line it up and just paint over it? does it need to be glued?


Please help :confused:

If you mean cracks in joins, Apply self adhesive fibreglass tape over the crack. Then stop it up with plaster topcoat (or if a small repair use polyfilla).
Sand smooth when set then paint.

If you mean cracks in sheets of fibrous plaster. There used to be available from hardware stores a sticky tape made for sealing minor cracks. Supposedly you only need to paint straight over it but I've found a bit of plaster over the top before you paint gives a totally invisible repair.

[silentC]

Paper-taped joints are stronger and more durable. I don't know the scientific reasoning but I do know that mesh taped joints can move and, especially in ceilings, they need to be back-blocked to give them support.

Paper tape is harder to install. If you don't do it right and it's too dry the tape will curl and lift the jointing compound away from the board. The mesh tape is dead easy because it's self-adhesive. It takes more clean up though because the jointing compound will squeeze out as you run over it with a knife and will require more sanding.

If the sheets are joined on a nogging then you will probably be OK to use the mesh tape for the walls. If not, you're better to go with the paper because if someone leans against the wall it might open up. It's best to use paper tape in corners in any case. I'd prefer to use paper tape on ceilings as well.

[Barry_White]

I built my house 20 years ago and I used the fibreglass tape because as I hadn't done any plastering before and it was much easier to use. On advise from a plasterer I only used finishing compound, three coats.

Now after 20 years I have cracks every where in the joints and wish I had persevered with the paper tape. Now maybe I should have used setting compound first and finished with the finishing compound. I don't know.

My opinion go with the papertape,

[ozwinner]

But Baz!

How do you know the results would have been different if you used papertape??

Al :confused:

[Barry_White]

A few reasons Al.

I have seen 30 year old houses with paper tape and no cracks in the joints.

I have a steel framed house which is more compatable with plaster board from a contraction and expansion point of view, than what timber is.

I am built on a concrete slab with a Granite substrate.

Apart from that there is not one crack in any of my cornices, even in the corners.

[Jacksin]

The problems I have encountered using paper tape is that if you play with it too long it will bubble all over the place (no smart comments Please!!) for this reason I was advised to use the mesh tape. I wonder in hindsight if I was loading too much on the first coat?

I have used base coat etc and all finishing compound and I cant see any difference.

I guess I just wasnt holding my tongue right
Jack

[journeyman Mick]

I've never seen a contractor use the fibreglass tape, but as has been pointed out it is easier to use. Fibreglass tape should never be used on villaboard. Paper tape is much stronger-try to tear a piece of paper tape by just holding it in both hands and pulling it apart, I doubt you'll do it. Now try it with the fibreglass tape, it'll come apart without much trouble at all.
Barry,
the reason your joints are all cracked was because you used 3 layers of topcoat. The topcoat has a higher shrinkage rate than the basecoat and should only ever be skimmed on. The idea is tha you use as many coats of base as is required to fill and then skim on some top coat. The topcoat becomes more dense as it shrinks, thus giving a better surface for a finish sand.
I use fibreglass tape and premixed total joint compound and premixed topcoat, but I only ever do small jobs. Anything that would require more than two or three sheets of board will see me reaching for the phone to get a plasterer in.

Mick

[princhester]

Mick what I have is total joint compound. It says on the bucket that I can just use three coats of that. Do you agree or would you use it only as a base layer then use a top coat?

[Barry_White]

Barry,
the reason your joints are all cracked was because you used 3 layers of topcoat. The topcoat has a higher shrinkage rate than the basecoat and should only ever be skimmed on. The idea is tha you use as many coats of base as is required to fill and then skim on some top coat. The topcoat becomes more dense as it shrinks, thus giving a better surface for a finish sand.
I use fibreglass tape and premixed total joint compound and premixed topcoat, but I only ever do small jobs. Anything that would require more than two or three sheets of board will see me reaching for the phone to get a plasterer in.

Mick

Mick
When I built my house I don't think premixed total joint compound was around only the powder and I couldn't work fast enough before it went off.

Although it was about 10 years before the hairline cracks started to appear and that is mainly where the sun hits the walls. Although some of the ceiling cracks appeared a bit earlier but only in the lounge. The rooms where the sun doesn't hit there are no cracks.

[journeyman Mick]

Barry,
too late now I know, but adding lemon juice will slow down the cure of the powdered type plus mixing as little as possible helps too. The more you mix it the quicker it goes off.
Princhester,
3 coats of TJC is okay, 2 coats of TJC and one of topcoat will give you a smoother better finish.

Mick

[Barry_White]

Mick

I suppose Spackfiller or No More Gaps will fix the problem when I get round to painting again.