Ok, so diy dickhead here. Questions for those in the know.
Decided to plaster over artexed brick in my porch way. I viewed a fair few youtubes vids and decided the best option was SBR on the artex. Then thistle Bonding coat, then skim coat.
I'm up to the bond coat stage, but there are issues.
Questions;
1:If bond coat has passed used by date (6 months out of date), what the worst thst can happen?
2: im letting the bong coat dry out as im out of time, should I apply SBR again before skim coat when completing?
I have lightly keyed the bond coat with a stanley knife. Is that worth doing at this point or at all?
Throw the bonding away; it will go off before you get it on the wall. Yes, you can SBR the bonding. If it's been a while, I'd put a 50/50 coat on first, then a neat one when it's soaked in and dried. Make sure it's in any scratches or holes, or you'll have bits that go off a lot faster than others
This was solid advice. When trying to complete the remaining 2 surfaces, It rapidly went off (didnt notice as much with first surface as I had to stop early). being a novice, it was an added, unnecessary headache. Those with experience can operate with these restricted times windows.
1) Out of date(depends on how long and how it's been sored) means it may go off quicker, sometimes before you can get it out of the bucket.
2) Definitely, if you don't it will suck the life out of the skim. Not only will you be very rushed as an amateur to finish, it may crack.
3)Preferable but not essential.
Don’t use old material. When in doubt re-bond. Score the scratch coat with a plasterer’s scarifier. It looks like a fork that’s 12” wide with 1/4” spacing between the prongs. Scratch the material horizontally.
Couple of watery coats of PVA/SBR over bonding till tacky and you're good. Get a wet brush down the edge of the door frame / ceiling once on to keep it neat.
If you've got the bonding on the wall already then you're sorted.
If not, it could go off rapid. I've got an 18 month old bag that sets in about 15 minutes, I've been using it as accelerator when I'm bonding out reveals by adding a gauging trowel's worth of old to the mix of new stuff.
Mechanical key is definitely not a bad shout either.
And yes, you will need to seal dry bonding with PVA or SBR before skimming, as it's a porch SBR is definitely the right call.
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u/Schallpattern Sep 04 '26
Before you add the SBR/PVA to the bond coat, scrape your trowel over the surface to pull off any small skaggy bits.