Skimming a ceiling in two parts.

[Rednadnerb]

I have just plasterboarded a ceiling and am going to have a go at skimming it. It is quite big, bigger than any wall I have skimmed before so I was wondering if I could do it in two parts. Has anyone tried this? would the join always show?

Thanks

Brendan.

[Phil L]

It's more difficult doing it in two parts than doing it in one, and yes, the join will show if you intend painting it, if it's being papered then no it won't show (as much)

If you intend doing it in two (not reccomended) then where you finish off on day one, make sure the plaster is chamfered to nothing over about a foot wide, then on day two, you'll have to unibond (PVA) this foot wide strip (and a few extra feet of skimmed ceiling) and skim over it, going onto the part that has been skimmed the day before.

Better idea is to get someone to help you, even if they are just mixing and cleaning up it makes your job easier and you can pay full attention to the ceiling, better still if they can plaster....

[JimK]

not tried it on a ceiling but if I had to I'd:-

do part 1 and at the edge to be continued later skim out to nothing, and polish it out smooth to nothing too makeing a "transition area" as it were

- make some marks on the walls where the full thickness part stops. Next time thoroughly wet the whole of the "transition" area and also back into part 1 with water (i use a cheap hand held pump up garden sprayer).

Old plaster sets new off quicker so there may well be mileage in starting part 2 at the far end and working back towards the join so hopefully you'll have enough time to sort out the transition before it starts firming up too much...

or maybe you could do it in 3 parts if you start hitting snags and do a central transition as the 3rd and final and smallest bit?

Cheers JimK

[Andrew Gabriel]

Join will show if you know it's there. If only you know, that probably doesn't matter. In many houses, you'll find there's a join somewhere up the staircase wall which goes from the ground floor to the first floor ceiling, but you probably didn't notice it until pointed out (or you looked after reading this, sorry;-). Often it's a horizontal line level with the ground floor ceiling or upstairs floor surface.

When I join, I do the opposite of what Phil said. :-)

When you've got the first coat on, as far as you're going with it, use a scraper (or the end of the trowl) to remove the edge before it sets so you have a clean step where the plaster finishes which is the thickness of the main body of the plaster (and not thicker or thinner because it's at the edge).

Another tip is don't make this step a straight line - the eye is very good at noticing straight line inperfections, but much less good at noticing a random edge. (OTOH, if it's going to be bad enough to be really obvious, it's probably better if it's straight;-)

When you do the second coat (applied whilst the first is still wet and ideally not quite set), you do the same again, but about a foot back from the step of the first coat (and wait long enough that the first coat is set so you don't do too much damage scraping it).

Now, when you do the other half, for the first coat, you plaster up against the step edge of the other side's first coat. Then you'll probably need to PVA the gap between the two steps as this will be dry, before doing the second coat. (Avoid spreading PVA over the face of the existing top coat though.) Again, you take the plaster to the second step edge. You'll probably need to wipe/scrape off any plaster you smear over the first half's second coat.

If you don't separate the edges of the two coats, you'll never manage to join them and maintain even thickness (which would then show). The reason for the sharp steps is it gives an edge to plaster up against (even though it's only a mm or two) and helps ensure the plaster thickness doesn't change at the join. Also, I don't find plaster can be feathered to nothing (unlike something like polyfilla).

[Stuart Noble]

I reckon ceilings are about 3 times more tiring than plastering a wall, so I'd be doing it in 6 parts :-) I find Artex more forgiving than plaster and probably better suited to working in stages. It feathers quite well and stays workable for longer.