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.

MickMick
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.

[Harry72]

Dont use that mesh tape it is crap, ask any plasterer/flusher.
Come to my house and I'll show you mesh V's paper... currently doing my whole house now(well I was until I had an operation done on my lower back...) I started using mesh, then a plasterer mate came around and laughed at me for using it. He showed me how to apply the paper tape(its easy... very)and that stuff hasnt cracked yet, all the meshed area's will have to be scraped out and redone because every millimeter of it has cracked!(the G/rock is glued directly to solid brick and its still cracked)
Barry, Mick is right you should have used basecoat 45, topcoat is just that it fills sanding marks and very slight imperfections!

[princhester]

Thanks all.

[JDub]

Sorry to dig out this old thread all.....



but Im about to embark on my first crack (pun intended) at plastering.

I am filling in a doorway and also removing a dividing archway.



From what I understand mesh tape is easier to use but paper tape is stronger.

Any tips/instructions on how to use the paper tape effectively? :eek: :o



Cheers

Joel

[BrisBen]

Joel

The real key with paper tape is bedding it in. Most mudslingers (plasterers) run a thickish layer of basecoat with a 4 inch knife over the join then bed the tape in. Once it is in place they will run the knife over it again, smoothing it into the join and removing the excess mud - but it will take a bit of practice, if the tape bubbles - rip it up and start again - if you hit paper tape when you are sanding it makes a bit of a mess.

If you are going to do a bit of plastering buy decent broadknives (or trowels if you are more comfortable with them) - keep away from the plastic stuff, plaster is abrasive and you will lose the edge on them quickly. Carbon steel is easier to use for a starter as the mud sticks to them a bit better, but clean them well and spray with cooking spray when you have cleaned them to store. Mud will slide off the stainless ones a bit to easily for the uninitiated.

Final word, start with smaller tools and work wider on joins - say 4 inch first coat, 6 inch second, 8 inch final, a butt join of this type should really be about 400mm wide when finished pre sanding. On thicker in the middle then feather the edges each coat. CSR have a pre mixed multi purpose compound that will probably make it a little easier for you.

hope this helps

BrisBen

[Jacksin]

Not wanting to stir the pot further but---

Looking at a DIY gyprock installation guide put out by CSR Gyprock that I recently picked up, I see they recomend Gyprock 'easytape' which is the meshed type with built in adhesive.

I think where I went wrong with paper tape was after spreading jointing compound on the joint and running the tape over it so the excess compound squeezed out, I tried to load more compound onto the joint before allowing the tape to dry, ending up with bubbles here and there.

I have always been wanting to try the mesh to avoid problems, but if its not as strong-----
Jack ;)

[Harry72]

And it will crack at the slightest movement of your house...
The paper tape is easy to use, the way I been do it.
Slop on a decent amount of mix(stiff), I cut the lenght before starting. Line the start up using your finger pushing in the centre of the tape, holding the tape out from the wall with your right hand(im RH'ed)with you arm streched out, this will help you keep it lined up. Using your LH fingers in the centre of the tape walk along the lenght of the wall pushing only the tape centre into the mix.
Then using a 4" plaster/broad knife from the start push the rest of the tape in the mix using a sliding action along the lenght, dont put too much pressure on it or you'll squeeze out to much mix and end up with excess/stretched tape bubbles.
Once thats done while its still wet slop on the main fill coat.

[JDub]

Thanks for the detailed explanations guys, that will really help me out.....:D

Do you think the internal corner plastering tools are worthwhile or are you better off just using the broadknives for the internal corners?

With the external corners I assume there is no special tools etc needed when using the metal beeding edges, just use the broadknives and feather the outside as with the other joins......?

Thanks again,

If it works I will post some before and after pics:o ;)

Joel

[princhester]

I've now finished (sort of, read on) my plastering job. It went well in some areas, but in others the compound in the joints seemed to swell when I painted so that it is now slightly raised and a bit ugly. I'm trying to work up the necessary head of steam to sand it all off and repaint.

JDub, I found the internal thingy of limited if any use. I found you could do the very corner itself OK, but you needed to use an ordinary knife to smooth out from there.

[johnc]

The internal thingy is pretty useless in the plastic version as it tends to deform in use and wears quickly, however there is a stainless version which is OK. I use it to load on the material, clean (feather) the edges with a plasters trowel and use the internal angle tool to give a nice clean line at the finish, a gentle swipe down the full length seems to give a tidy result. To be honest you can keep the broad knives and plastic of any kind I've stuck to a plasters trowel, paint scrapper, small tool and internal angle tool, but then I'm no plasterer so perhaps what I don't know doesn't hurt. I've noticed some plasterers run the paper up the corners before applying plaster and then trowel over the top with base coat, and then the final top coats later, its what I've done and no cracking but am I just lucky? Or is this a case of not reading the instructions again before jumping in feet first, Dohh.

[BrisBen]

A lot of guys will "flat tape" internal angles on the side that doesn't run through the wall - so that the only wall that gets the plaster is the wall that runs at right angles to a perimeter wall for example, remember to sheet the perimeter walls first so they butt right up to the studs. A clean cut sheet butting up to another sheet in some circumstances may only need a little "no more gaps" or similar, giving it a little room for building movement.