Replastering old plaster.

[27188]

Just started enjoying plastering. My question is why can I not plaster directly only old plastered walls. Walls brushed clean. I have skimmed with multifinish and it seems ok. Do I have to prep with 50/50 PVA each time and why?

Thanks
John

[wine~o]

The main reason not to is that skirtings/architraves will look odd, light switches and sockets may also need longer screws fitting..

As to the 50/50 Pva/water, 1 part Pva to 4 or 5 parts water is the norm, the pva is there to control suction/ stop the plaster drying out too quickly.

[27188]

Thanks. Always like to know why I am doing something. Just to check, it is not about bonding so scould put it on 4/1 night before?

[wine~o]

If you do you'll need to do it again the next day, apply the Pva, leave until it's gone "tacky" then crack on.

[27188]

Ok thanks

[27188]

Hi, I am plastering small areas at a time at the moment. Want to do 1/2 a wall at a time. How do I join up the plaster sections to give a clean smooth finish? Any ideas,

Thanks
John

[cotswold builders]

Fit a 3mm thin coat stop bead ( the wrong way round ) so you can plaster to it then remove when drying leaving a clean edge to skim to.

[wine~o]

Hi, I am plastering small areas at a time at the moment. Want to do 1/2 a wall at a time. How do I join up the plaster sections to give a clean smooth finish? Any ideas,

Thanks
John

Not ideal. put a batten up about halfway along the wall. plaster up to it. Remove batten once dry.

Plaster other side but dampen where the join will be... You'll probably need to sand along the join to get a better finish.

EDIT or what Cotswold said.

[27188]

Hi, I am plastering small areas at a time at the moment. Want to do 1/2 a wall at a time. How do I join up the plaster sections to give a clean smooth finish? Any ideas,

Thanks
John

Not ideal. put a batten up about halfway along the wall. plaster up to it. Remove batten once dry.

Plaster other side but dampen where the join will be... You'll probably need to sand along the join to get a better finish.

3mm batten helps get the layer of plaster correct depth, good
EDIT or what Cotswold said.

[London mike 61]

If you are going to do half a wall at a time then ( as long as the first half is hard from the day before ) after removing the stop bead , you should be able to blend the two together by giving the join a rub over wth a sponge float and a light flick over with a wet paint brush.
Depending on how you get on, you may only need to use the paint brush which essentially turns the plaster into a wet mix and is easier to feather out.
I’m NOT a plasterer just diy but this is the best way I have found to blend two surfaces together.

Mik

[fin]

ya could always put a line of scrim on the wall. then plaster just past it. then when its jus starting to set after youve flattened it off pull the scrim off leaving a straight edge. obv youd have to scrape off whatever plaster went past the scrim.