Villaboard butt joints using paper.

[JDarvall]

Hello. Need some help on plastering.

I'm putting up some villaboard in my laundry. Never done it before. So, I'm taking my time with it, so I get it right. Screw the wife and the mother-in-law and their incredible impatience I say ! :D ...I don't want to have to do it again, if I stuff it up, because I rush it. I can't afford to employ professionals.

Anyway, the villiaboards already been cut, and resting up against the walls. Haven't nailed them in yet. What I'm nexted faced with is joining them. Its recessed plaster, as you probably know. So, where each piece of board meets the next, there's two recessed edges butting together. The combined recessed area at this butt, is 2 and 1/2 inches...... I got a picture here to make it clear.....That first picture. Most of these joins do not reside over studs or noggins. The corners of the room do.

Went to bunnings, and on there advice, I bought.... 2" fibreglass mesh tape, and a tub of 'pre-mixed total joint Cement' ...CSR products. That 2" mesh fits well into that recess.

But, I've been just told that 'paper' is the go, instead of fibreglass. Fibreglass fails, says the experts... So Bunnings arn't experts ? :eek: :D

ok, I want to get it right, so I'm willing to try and return this stuff, even though I've lost the reciept, and buy the 'right' stuff.

From what I've read from previous threads on this is...you lay down a thickish layer of basecoat down this recess with a 4" broadknife. Is this right ? A 4" knife being wider than 2 and 1/2" would mean your bedding it in flush with the rest of board. But because you want to put more than one coating on I'd imagine you wouldn't want to make if flush first. ????

What I'm after is a procedure using paper tape. Appreciate any help.
Would it go something like this ? Based on what I've got from other threads.

1 - spread a thickish layer of basecoat down the joint first.
2 - push the paper down smoothly...pushing down the centre of the tape.
3 - run a knife down it to set the tape in. (knife smaller than 2 and 1/2" right so it fits into recess area )....not pushing too hard so that it doesn't squeeze or bubble out too much...

That second picture shows what I'm visualising. :o

Now, what I do ? Do I start putting down the topcoat. And how many coats of it ? Letting dry between each coat right ? Or do I just put down as many coats as needed to fill up the resess completely to a flush finish ? Then sand and paint.

Thanks Jake

[echnidna]

I cheat with paper tape
I glue it to the plasterboard with pva.
Plaster shrinks as it sets so just fill flush with basecoat.
1 or 2 coats of topcoat.

[mic-d]

Well I'm yet to have a joint with fibreglass tape fail yet. I know the story poo pooing it and I even used to spread it myself, but many plasterers I've seen and talked to use it. I have joints that are now many years old and they have not failed. But I would use a base coat which sets in a short time for the first coat rather that total joint compound - finish the joint off with that tho'. Don't use it anywhere you are tiling either, tile adhesive doesn't stick very well to it. In those areas tape the joint and fill it with flexible thinset tile adhesive.

Cheers
Michael

[Gaza]

Dont forget to use a wet area compund, not the std stuff.

[derekcohen]

Most of these joins do not reside over studs or noggins.

Jake

With the plasterboard walls I have made in the past (admittedly not for about 10 years), I made sure that all butted edges were nailed to support battens. My reasoning was that any movement would promote cracking in the plastered joints. Are yours going to be rigid enough?

I never experienced any problems with fbreglass tape. Never heard this before.

Regards from Perth

Derek

[JDarvall]

Thanks for all replys.

Well, maybe I should just use the fibreglass tape. ? . Just use what I've got and be done with it.

Its just I read a thread from this forum, from early this year, where most of the posts said that paper was stronger than plaster. That all plasterers use paper. That when you pull paper apart in your hands it has more resistance than if you do it with the mesh. One guy blamed cracks forming in his walls, put up a few decades back, due to the use of mesh; that he wished he used paper instead.....so, its hard to know what to think, ..... :confused:

One of those, many ways to skin a cat things, I guess.

Mic-d...... Thanks for that 'flexible thinset tile adhesive' tip. I will be laying splash tiles.

Derek, I'd say your right. That it would be better to have joins over somekind of framework. However, to do that now, would mean putting in a few studs.
Probably anything that will improve its strength the better. Especially since its an old house that has already shown its prone to movement.

I might divert my attention to other things for a while. Keep asking questions and see if the problem sorts itself out.

Thanks again.

[Marc]

Hi Apricotripper... paper is stronger, yes, but harder to use. Use the autoadhesive mesh on base coat.

That all- in- one stuff is the pits, you can only apply it in thin layers or it drips out of the joint. Find base 45 or 60 so it gives you time, and don't prepare too much at one time. Remember to poor the plaster in the water and not the water in the plaster. If you are going to tile over the villaborad, you don't need to apply top coat. Just give it a second coat of base.

As for your concern of unsupported joints, what you do is you screw the villaborad pannels horizontal. The shorter sides will be vertical and the longer side horizontal. I cut the villaborad in a way that the end of the panel finishes in the center of a stud (vertical timber) so that that joint is fully on top of the wood.

The longer horizontal joint meets a stud every 450mmm and that is support enough. I wouldn't make a joint that lands between two studs for all it's length, but if you have cut your villaborad already, I wouldn't cry over it.
Just add a couple of noggins under that joint so that it adds some support to it.

An important observation is that studs are hardly ever properly aligned so that you need to use stud glue if you want a stright flat wall. The stud glue once hard will fill in the gap between your stright villaborad and your crooked frame. You can check your frame with a stright edge and see how bad or how good it is.

Of course many point will tuch the board but some will be away from it and it could be one centimeter or more. When you screw the panel against the studs, you must make sure you don't go all the way on those studs that are not aligned. On those just tighten the screw enough to keep it in place, when the glue is hard, give it 24 hours, you can go over those screws and tighten them more so that they dig in the board and go flush. But if you don't it is still ok since you are going to tile over it.

[JDarvall]

Thanks Marc. Great advice. so...

- I'll just stick a few noggins accross for support.
- pour plaster into water.
- no topcoat where I tile. Just another coat of basecoat.

Might be a stupid question. But do I put a basecoat down first before the mesh ? ...cause I thought your supposed to put the mesh down first. Then basecoats, then final topcoat.

Your so right about my studs being out of alignment. Miles out in places. I've already screwed in many buffing pieces to support a flat wall. Countersunk the screws deep. Seemed very fiddly....I ran about 3 string lines from one corner of the room to the other for each wall. Then, with the electric planer just planed at those buffing pieces to get all the humps out. Seemed to work. But fiddly. And then I forgot myself and let one of the strings drift towards the planer while it was still on, and wound the string in deeply into it. :o Took good 15 minutes to cut it out. :D oh dear.

But thanks for that stud glue idea. Should I still be out, I'll just use it.

[savage]

I cheat with paper tape
I glue it to the plasterboard with pva.
Plaster shrinks as it sets so just fill flush with basecoat.
1 or 2 coats of topcoat.

I did the PVA thing with fibretape last night worked a treat!.Didn't shrink of course!...I know it is already sticky but it really became a strong bond, just needs a finishing coat and light sanding!...Good idea for both!..:)
savage(Eric):)

[Marc]

Thanks Marc. Great advice. so...

Might be a stupid question. But do I put a basecoat down first before the mesh ? ...cause I thought your supposed to put the mesh down first. Then basecoats, then final topcoat.


The auto-adhesive mesh is designed for "beginners" who would have otherwise difficulties with the paper tape and you glue it to the Villaborad and them apply the plaster.
Whoever, I don't do it that way. Working on the fact that the adhesion of the mesh to the Villaborad is temporary at best and that by sticking it to the board, I will reduce the surface of plaster that cements to the board by probably 25%, I give it one coat of base, and then slap the mesh into the plaster. Works for me and in theory should be stronger. Of course you cover the mesh with another coat straight away. Once dry sand the bits that stick out and give another coat of base. Now you have a strong joint. If you are going to tile over it, give a generous coat of Boncrete so that the tiles stick better to the board and joint. Dilute according to the instructions on the bottle.

[JDarvall]

Thanks Marc. Will give it a go after work tomorrow.

- base coat then mesh and base coat over that. Dry, sand, then another base coat......Do I use topcoat at all ?

[Marc]

Not if you are going to tile, yes in the parts that are to be painted, top coat is much more easy to sand and to get a nice smooth finish.
Pre mixed top coat is good, but.... do not use premixed base or "all in one", in my experience it is realy bad.

[AndrewPatrol]

Dont put any base on first, trying to put mesh in it after is messy. Just put the mesh on (remove dust from board) fill joint flush or under with base (wetarea base can be used but do not let it stand proud of joint - its rock hard and a bugger to sand) . let dry then apply another coat of base. I usually dont worry too much about first coat 'cept to make sure its flat. "holidays" can be filled by second coat. Try to feather out this 2nd lot a little to about 120/ 150 mm . after drying ONLY topcoat with your miracle all-in-one goo where you wont tile.

Miracle goo is only useful for topcoating. BTW I've used mesh tape heaps, havnt cracked a joint yet( may happen on butt joins if its sanded too much, but that can happen to paper as well. Totally agree with nogs to back your verticle joins. should have laid the sheets sideways, oh well , next time.

Take two offcuts of villaboard out side, nail em to a bit of chipboard and practice on it.

[spartan]

As a side question what are people using to cut Villaboard with?

[echnidna]

trimming knife

[JDarvall]

I found one of those big plaster cutters to work best. You know, the ones with long handles that you bring together like bolt cutters. To me, faster than using that knife. But then the knife was good for cutting out window slots and the like.

and,,,thanks to Marc and AndrewPatrol for there sound advice.

[mic-d]

As a side question what are people using to cut Villaboard with?
A score and snap knife will do, but a guillotine is best. An old hardpoint saw for cutting out windows/doors/alcoves once the panel is fixed in place. A hammer for making holes but a hole saw or circle cutter is better.

Cheers
Michael

[AndrewPatrol]

Proper cutters (like giant sort of scissors -bout 600mm long) or a diamomnd blade in grinder works well too.