Plasterboard corners

[ban-all-sheds]

I'm planning to dot'n'dab some walls, then paper/paint the plasterboard, i.e. no skim coat.

What do I do about outside corners? All the beading I've seen goes on top of the boards, which would be fine if I was having a skim coat, but....

 

[RonnyRaygun]

Don't know if this is the right way, but I tacked on some metal angle beads and filled over with Gyproc Easi-Fill then sanded and blended to a nice finish for my external corners.
Probably be told by all the plasterers I've made a grave mistake now...

Other options here: http://www.british-gypsum.com/products/plasterboard___accessories/gyproc_beads.aspx

 

[r896neo]

Unfortunatly even when dry lining you need to use at least the metal reinforced tape for the corners and then simply feather in away from them.

I haver never tried it but if you were using really thick lining paper you may be able to get away with the tape only but i doubt it would be much of a result.

 

[ajrobb]

Gyproc Corner Tape or Gyproc No-Coat or similar. Blend in with Easifill and rub down.

 

[PrenticeBoyofDerry]

Best method is to use a thin coat bead
like this

Untitled

• PrenticeBoyofDerry
• 26 Oct 2009
• 3

http://www.diy.com/diy/jsp/bq/nav.j...ndid=9273226&ecamp=trf-005&CAWELAID=266888346
available at most merchants and sheds.
Then apply easifill, it will need two/three coats of easifill http://www.british-gypsum.com/produ...ries/gyproc_accessories/gyproc_easi-fill.aspx and sand down after each application has dried, using 150 grit dry-lining sandpaper. The final sanding should produce a smooth even surface and is best sealed with a primer, prior to papering.
The beads will need to be nailed or stuck on, a spirt level will be required to get them flush.
If you use flex corner tape and are a novice, you will find it difficult to fit and could tear the tape when applying joint compound to it, which makes a dogs rear end of the job!

 

[ban-all-sheds]

I guess what I was imagining was the existence of something like the blue item in this sketch:

(Pink is filler)

I've drawn it with square edge boards - tapered would work better.

Still - if the external beading looks OK when feathered in I'll go with that.

I was going to ask if this stuff was any good, but that was because I started this reply hours ago before ajrobb and pbod posted....

dry-lining sandpaper.

Never knew there was such stuff. What's the difference between that and ordinary sandpaper? (Or aluminium oxide which I usually use)

 

[PrenticeBoyofDerry]

Are the boards you are using 12.5mm?
Is there a reason they are not butted up together on the corner (pink filler area) or have I missed something?
The sandpaper used in dry wall/joint taping is less cloggy.
Because joint compound is soft, you don't need a coarse-grit paper to sand down.
Coarse-grit paper will leave sanding marks.
So 120-150-grit is best to use.

 

[ban-all-sheds]

Yes, they are.
Because I was worried about the strength of such a corner.

 

[PrenticeBoyofDerry]

Ideally the corners should have been butted up, but a thin coat will cover over the corner.
I would advise using thin coat beads on external angles, as they are more durable to knocks and don't damage as easy as the flex, paper beads do.

 

[ban-all-sheds]

The sandpaper used in dry wall/joint taping is less cloggy.
Because joint compound is soft, you don't need a coarse-grit paper to sand down.
Coarse-grit paper will leave sanding marks.
So 120-150-grit is best to use.

It wasn't the grit size I was questioning, it was in what way 150 drywall paper differed from regular 150 aluminium oxide or silicon carbide paper. Dunno if my stuff is open coat though.

But I tend to use 320 for filler on plasterboard.....

 

[ajrobb]

I was going to ask if this stuff was any good, but that was because I started this reply hours ago before ajrobb and pbod posted....

I've just used NoCoat over butted cut edges (i.e. not tapered edge). The filler doesn't cover the plastic corner just the paper edge and plasterboard. It's at the top of the stairs and has already had a few knocks but is holding up OK. I was going to use the metal reinforced tape but TP withdrew it due to "production problems". They offered me NoCoat at the same price.

I finished off with one coat of Gyproc Driwall Primer (TP driwall centres stock magnolia but knock them down to £38 for 10 litres or they try to charge over £70) and one coat of emulsion. B&Q advertise primer at £37.96 but have been out of stock for ages.

I used paper tape and Easifill to join tapered edges and internal corners. I didn't skim or line the walls with paper just primer and matt emulsion. I think the finish is as good as I get with paint over lining paper. It shows up the old plaster walls - I should have lined them.

I've also heard that you can add 10% water to emulsion as a primer.

The primer is NOT recommended if you later want to use a steamer to strip wallpaper (use sealer instead).

 

[PrenticeBoyofDerry]

It wasn't the grit size I was questioning, it was in what way 150 drywall paper differed from regular 150 aluminium oxide

There is nothing wrong with using aluminium oxide paper, it will do the job fine.
The difference between the specialised paper, is that it tends not to clog the sandpaper surface as much and will last awhile longer.

 

[ban-all-sheds]

A thought has occurred to me - the wall where I have this concern about corner strength is pretty small - only about 800mm wide at its widest, about 500mm where there's a window.

Any reason why it would be mad to use MDF instead of plasterboard?

 

[PrenticeBoyofDerry]

It's carp and combustible!
Plasterboard is cheaper and offers a better surface to paint and fire resistant for about 30mins and joint taping compound would struggle to adhere to it. That's if your jointing and beading with the stuff.

 

[ban-all-sheds]

I was thinking about using it so as to avoid needing beading, it being tougher than PB.

There'd be no joints needing filling.