black mortar

[1john]

i have a 1920's house under renovation at the moment. It is brick built except for the partition walls upstairs which appear to be poured black mortar as they are not thick enough for a brick or block, apparantly this is the way the local authority built them around here

anyhow, the white skim coat (lime?) has become unbonded from some of the walls in as much as i can easily remove it with a scraper. The black mortar below sounds firm and is fairly flat, can this be PVA'd and skimmed with multi finish or do i need to dab them? I would prefer not to dab some walls as they are in small rooms and every inch counts.

 

[Alastairreid]

pva then base coat (bonding) then skimmed by the sounds of it.

 

[trowelmonkey1]

yeah i agree AR

 

[1john]

thanks for the advice chaps. I had never skimmed anything really before saturday and i cut my teeth firstly on a sloping ceiling, about 1m x 2.5m. pleased with that, so today i did a small ceiling and wall at the same time, both about 2m x 2,5m

I am pleased with the finish, so much so that i would have paid well for the finish i acheived which suprised me, although i have spent alot of time on jobs watching people plaster out of the corner of my eye over the years.

Anyhow, the bonding coat, can anyone talk me through how it should be applied, like thinkness and number of coats, should i try and flatten it with a feather edge? can i apply a skim coat on it when it's wet, similar to skimming or should i let it harden.

Sorry for the amount of questions, hope you dont mind advising