Repairing plaster - advice needed

[philipb82]

Hello, I'm planning on repairing some cracked and hollow plaster in my spare bedroom. I plan to remove the affected area probably back to brick. So heres what i propose to do: 1. PVA or dampen the brick then do a sand and cement base.
2.PVA or dampen the sand cement base then apply some patching plaster, maybe polyfill.
Would this be the right way to do it? If i use PVA then how much? Do i apply the sand cement when pva is dry? Just a few things i need to get straight before i start. Thanks. Phil

 

[1john]

Whats on the wall at the moment?

Normally I would remove the excess, if it's quite thick then I wont PVA, i will fill out with one coat plaster, rule off flush with the wall and then once it's firming up trowel it in a little. once that has set i will apply and sand as many coats of easy fill are required to get an acceptable finish.

 

[philipb82]

Its plaster and the undercoat is that browning stuff, our house is a 1950s construction. Some of the browning is crumbling so thats why i think its best to knock that off too. Phil

 

[PrenticeBoyofDerry]

I would use the same basecoat than the existing one, so browning.
This can be applied at depths of about 12mm, anymore and I would be thinking of a couple of visits.
The walls can be dampened down prior to applying basecoat, you can also apply finishing coats to the browning, as starts to firm up, no need to wait for it to completely dry.

 

[philipb82]

Thanks for your reply, thats made it clear. So can i not use sand cement as a basecoat even if i'm applying it 2 bare brick? Phil

 

[roughcaster]

Let's take a step back for a minute. You say the undercoat is Browning,, but has it a dusty, "sandy" texture,, the colour of sand,, that powders away as you rub your hands over it? A pic would be very handy.

 

[philipb82]

Hello roughcaster, it is how you describe it. I have posted a pic.

I say its browning because thats what i've been told it is.
Phil

 

[WalksWithTurkeys]

I would not use Polyfill, it is hard to sand. For small areas Easi-fill is much easier to use. I don't know how wide and deep you can go with it though. I'm a novice, and a builder doing some work for me recommended Easi-fill. I've done invisible patches to 6" across without much difficulty.

 

[stevethespreader]

Hello roughcaster, it is how you describe it. I have posted a pic.

I say its browning because thats what i've been told it is.
Phil

by the look of the cracks it looks like it has crazed and blown where it has dried out to quickly

 

[philipb82]

Thanks for the replies. The plaster that i intend to repair is old so i suppose it is to be expected. I'd be more worried if it was new plaster! Phil

 

[jrplastering]

is that pic super zoomed in or is that plaster really really thick, how big is the hole??

 

[philipb82]

I took the pic close up! The crack is about 4.5 inches across and approx. 2/3mm thick

 

[jrplastering]

haha wassnt too sure it looked like either a really zoomed in pic or not and the plaster was mega thick.
im not sure if that is browning mate could be a lime coat, scratch it a bit and see if thiers hairs and small stones in the coat

 

[1john]

That looks like grey carrolite bonding. I would just easy fill over that.

 

[stevethespreader]

could be a lime coat

a lime coat? lol looks more like browning or bonding to to me if i had to pick one i would go with bonding