Hello - and 1930s black ash mortar advice!

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Vix79

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Hi all

I’m a decently skilled DIYer looking for some advice...

I have a bedroom (outside) wall with large patches of blown plaster in my 1930s London house. The background is black ash mortar (horrible stuff!) that isn’t damp anymore but is very crumbly and dusty. After loads of research I’m thinking of PVA - bonding coat - skim as a solution. I’m looking for any advice relating to this: e.g product recommendations, how to prep the very dusty black ash, how to apply PVA coats etc.? The black ash is obviously v.high suction, but presumably if I PVA I can then use a low suction bonding coat?

Looking for majority opinions as there’s so much contradictory advice out there and I’ve started going round in circles!

Oh, and don’t say get a professional in. The quotes I’ve had are ££££ and I can’t afford it. The wall is small enough for me to at least have a go.
 
Bonding - lovely to use but ain’t for high suction backgrounds but you can PVA the heck out of the wall and then PVA on top of the bonding if it is feathered in at the edges or not getting skimmed same day
Why don’t you get a professional in to advise you and pay him for his time because snippets of info can be misleading
 
Hello - and 1930s black ash mortar advice!
 
Vix79 said:
Hi all

........30s London house. The background is black ash mortar (horrible stuff!) that isn’t DAMP anymore

Looking for majority opinions as there’s so much contradictory advice out there and I’ve started going round in commando
Click to expand...
The quotes are probably high because it's not a cheap fix

Why was it damp
 
bof said:
The quotes are probably high because it's not a cheap fix

Why was it damp
Click to expand...
Yeah. The quotes weren’t *too* high, per se. Just I can’t afford them!

Damp had come in from rainwater on outer wall thanks to dodgy gutter. Fixed now.
 
Have you added up the cost of the tool’s you’ll need?
trowel, hawk, handboard, (you need both of those on this site) buckets, mixer paddle, drill, spot boards etc
And compared it with the cost of a quote?
 
To clarify, it’s not that I resent paying a pro, it’s just that lockdown hasn’t been kind to us financially, we’ve just had a second baby 6 weeks ago and this wall is in the room our older boy needs to move into. Atm it’s exposed black ash (I’ve removed the blown plaster to check for any remaining damp in the background) and I need to get it sorted. No time to find the funds to pay a pro and as I’ve done many (admittedly simpler) patching/rendering jobs before I need to, and can, do it myself.

Any advice on the techniques I mention would be much appreciated.
 
Problem is there’s original plaster coving that won’t come off without disintegrating so it’s not an option. Otherwise plasterboarding definitely would’ve been my first choice!!
 
You’re going to do it aren’t you?
Techniques:
Watch loads of YouTube videos on rendering and plastering then try to do a practice wall somewhere even if you get a small sheet of plasterboard and fix it to the wall you’re going to work on in the end to give you a feel for technique then remove it after but the gear will react/behave different on ashen block than it does plaster boards
Oh and do post pics pls
 
Monkey Boy said:
You’re going to do it aren’t you?
Techniques:
Watch loads of YouTube videos on rendering and plastering then try to do a practice wall somewhere even if you get a small sheet of plasterboard and fix it to the wall you’re going to work on in the end to give you a feel for technique then remove it after but the gear will react/behave different on ashen block than it does plaster boards
Oh and do post pics pls
Click to expand...
Like I said, I’m experienced with rendering and patching. It’s more tips regarding prepping / PVAing the ash wall etc. as it’s not a straight forward job. Basic rendering and plastering skills I’ve already got down
 
Monkey Boy said:
Have you added up the cost of the tool’s you’ll need?
trowel, hawk, handboard, (you need both of those on this site) buckets, mixer paddle, drill, spot boards etc
And compared it with the cost of a quote?
Click to expand...
Tools? Tools? Who knew? You have'nt seen the foreigners - bucket and a bucket trowel to mix and finish with, no probs, cash please.
Ignore the coving, leave it alone, fix the board up to it, and keep your boy warmer. He doen't care about how it looks, sort it later whne he leaves home or you're flush.
 
Vix79 said:
Hi all

I’m a decently skilled DIYer looking for some advice...

I have a bedroom (outside) wall with large patches of blown plaster in my 1930s London house. The background is black ash mortar (horrible stuff!) that isn’t damp anymore but is very crumbly and dusty. After loads of research I’m thinking of PVA - bonding coat - skim as a solution. I’m looking for any advice relating to this: e.g product recommendations, how to prep the very dusty black ash, how to apply PVA coats etc.? The black ash is obviously v.high suction, but presumably if I PVA I can then use a low suction bonding coat?

Looking for majority opinions as there’s so much contradictory advice out there and I’ve started going round in circles!

Oh, and don’t say get a professional in. The quotes I’ve had are ££££ and I can’t afford it. The wall is small enough for me to at least have a go.
Click to expand...
Give the wall a coat of blue grit let it dry for 24 hours then skim
 
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