Query about Plaster

WageSlave_3

Hi all,

My query is more about the types of plaster to use. I have sections where the old plaster has fallen off (biggest is about one foot radius and the depth is obout 1 - 2 mm). I have never plastered before, so after much reading up, I picked a few sections and all went well with putting on the base layer. It looked a bit 'grainy' rather than a nice smooth consistency after a dragged off excess using a straight piece of wood but it dried out ok .

My problems have been trying to put on the final coat and getting it nice and marble smooth. I got the plaster to a fairly runny consistency (like melting ice cream) but just can't seem to get it to look good). Some parts are ok, but the odd section has a few lines where some of the larger pieces of aggregate have been dragged along as I have been trowelling it with the trowel dipped in water.

I am wondering if my problem might be the choice of plaster. I got a small bag of 'One Coat' and have used this for both base and top coat. When I mix it, it feels very 'grainy'... like it has very fine sand in it. I had expected it to be almost creamy with no grainy feel. It does seem to smooth to a certain extent, the bit that is driving me mad are the bits that scratch. I also have one section where it looks like air bubbles have popped while dring and it doesn't look good at all.

So if anyone could advise, you'll have the pleasure of knowing you have saved my sanity and a good deal of money before I give up and get a pro in!

Cheers,

WS

debbie42

Did you mean 1-2 cm? Can't imagine why you'd need a base layer otherwise?!

I've patched up the odd bit with the multi purpose stuff, but it never looked quite right. It was fine for taking wallpaper but woulld look really naff if just painted. I've also done a larger area with "proper" plaster (top layer = finishing plaster, I think?), and that was better, but still annoyingly lumpy compared to the smooth finish a professional can get.

Pretani

WageSlave wrote: »

I am wondering if my problem might be the choice of plaster. I got a small bag of 'One Coat' and have used this for both base and top coat. When I mix it, it feels very 'grainy'... like it has very fine sand in it. I had expected it to be almost creamy with no grainy feel. It does seem to smooth to a certain extent, the bit that is driving me mad are the bits that scratch. I also have one section where it looks like air bubbles have popped while dring and it doesn't look good at all.

So if anyone could advise, you'll have the pleasure of knowing you have saved my sanity and a good deal of money before I give up and get a pro in!

Cheers,

WS

don't buy those 'One Coat' bags. total madness.

Presuming that you know the plastering trade, buy bags of skim when looking to achieve a smooth finish. If your wall is a brick wall, plaster it with cement and them skim over with skim plaster. If your wall or ceiling is a stud wall and it's in bad shape, you need to add a layer of bonding plaster before you skim. this is like the 'one coat' bags you mentioned, it offers something for the layer of fine skin to bond to:D

WageSlave_3

Thanks. Unfortnately, I don't know the plastering trade but I'm learning. I guess from what you've both said, I need Thistle Multi-finish (it's wall rather than plaster board). Sounds like the one coat was not a good plan. Ok... shortcuts are out in future!

I did mean 1 -2 mm. So perhaps I should use the one coat as a base and proper finish plaster for the finish.

I intend to paint over rather than wallpaper and I have had to sand the walls, so its relatively smooth rather than totally. Have to trade off a competely smooth finish all over against the cost of a complete reskim.

Only last question is, does finish plaster have a finer texture to it or is it as 'gainy'.

Ohh, sorry, editing to add - are skim, as you call it, and 'finishing plaster' as I know it the same things?

Cheers!

WS

Pretani

WageSlave wrote: »

Thanks. Unfortnately, I don't know the plastering trade but I'm learning. I guess from what you've both said, I need Thistle Multi-finish (it's wall rather than plaster board)

the finish on wall is the same finish on plasterboard, the difference is the preperation, one is cement (wall), one is bonding (all in one)

.

WageSlave wrote: »

Sounds like the one coat was not a good plan. Ok... shortcuts are out in future!

Unless you've got a good level hand, I wouldn't atempt to put on the finishing coat.

WageSlave wrote: »

I did mean 1 -2 mm. So perhaps I should use the one coat as a base and proper finish plaster for the finish.

That would be fine, use it up on the holes.

WageSlave wrote: »

I intend to paint over rather than wallpaper and I have had to sand the walls, so its relatively smooth rather than totally. Have to trade off a competely smooth finish all over against the cost of a complete reskim.

best to re-skim the whole wall if you want to paint. trust me, no matter how much you think you've covered in the holes, the light will show them up.

WageSlave wrote: »

Only last question is, does finish plaster have a finer texture to it or is it as 'gainy'.

There's practically no grain to finish (skim) plaster. It's like talcom powder