PVA and Browning and thermalites???

19 Jul 2007
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United Kingdom
I know it says on a bag of browning that you shouldn't use pva prior to using it but why not!!!?

The only reason I ask is because when I use browning on thermalites the scratch coat invariably cracks from drying out so quickly and on big walls when I skim I have to work my nuts off trying to keep it workable.

I do damp the thermalite down first etc but they still suck like a whore on heat and I am getting no younger.

Anyone got any tips on how they manage high suction substrates or should I just do dot and dab like everyone else seems to??

A worn out old git!
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Forget your Browning and Bonding, Hardwall is the new "kid" on the block, when you've used it you won't go back to the others.....
I would agree with Roy about Hardwall & whilst not wishing to teach suck egs & all, are you damping down ehough & how thick are you putting it on? I prefer Hardwall but it will still craze if it's all too dry or you try & lay it on too thick in one hit.

I wouldn’t put Bonding in the skip though! It’s most suited to low suction backgrounds so would not normally be used for block work but still has its uses on a crumbly old block wall!
Thanks for replies.

As for damping down I even use a hose where its possible but you know what thermalites are like, they can be soaked in a bath and still dry out in 20 mins.

Scratch and floating go on no more than 10 mm each.

I'll give hardwall a go on my next job. I must admit I thought it was for low suction like concrete walls etc, but I bow to your experience. Do thermalites still need damping/soaking or do you pva when using hardwall?
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Hardwall can be also used on block work but seal & bond with PVA or a proprietary primer to control suction or you’ll be back where you started with the Browning.
thanks richard,

I took a look at a bag of hardwall today and it said on the back not to be used with bonding agents but substrates with high suction should be treated with gyp-prime.

BG site say no PVA as it doesn't do what their products do but then they would. :rolleyes:

I've searched this forum and it seems that most people just PVA thermalites first, but before I try it i just want to make sure that this is the case and that no one has had any problems.
Hardwall is the best backing for multi finish on the market. As long as you get a shift on with floating your walls early in the day, you can skim them all up a few hours later. So solving your suction problems when skimming, huge areas are attainable.

Ps. Dont leave it more than 24 hours before skimming or you'll be back to square one.....
Cheers guys,

Well I guess it is my age and I am just slowing down!!

Used hardwall today and I found it not that different from browning. Granted it didn't suck the first coat of finish in quite so much but I still had to work above my max heart rate!! :unsure:

Just have to price float and set jobs (aswell as ceilings) with a labourer in future!!
My motto is: If in doubt - get the PVA out. You can't plaster onto something with the properties of a Farley's Rusk. It doesn't matter how fast you are - it will dry before it has time to cure and will probably fall off later.

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