problems with sand and cement after a dpc.

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brimplas1

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im just after some advice as ive had a problem today with rendering after a dpc. 7 days ago i put the scratch coat on and with the house being empty for months ive had 2 dehumidifiers on to get it nice and dry for the top coat. today the walls looked nice and dry so topped them off, after a couple of hours in about 5 places the render started to turn to p*ss and slide down the wall. these 5 places were all at the bottom and about a foot square. the rest of the walls also dryed up very slowly as i had to go back at 7.30 to give it a good hard rub up and rule off and the gear was still pretty soft. do you think its just the weather / conditions and is there anything i can do to speed up the set without effecting its water proofing propertys ?
 
If it is dpc work with the amount of waterproofer in the mix (if done right ) why scratch coat out ? the top coat will hang about for a day , if i have read it wrong i,m sorry
 
I normally top off when the scratch is still green and never had any problems
 
i think that the scratchcoat has killed your suction. we apply the floating in two coats but always on the same day.
 
Same as others have said, all in in go or scratch coat and top when firm enough to take it.
 
It's caused by the fairy juice the magician Dpc people inject in the walls . When they take the magic injection lances out of the wall, some of the fairy juice spills on the bricks and your s+c won't stick to it
 
i couldnt really top it off the same day as it had to go on pretty thick to tie in with the existing plaster and door cases etc plus the scratch coat in a few places was very soft even when i left at 5pm.
 
brimplas1 said:
i couldnt really top it off the same day as it had to go on pretty thick to tie in with the existing plaster and door cases etc plus the scratch coat in a few places was very soft even when i left at 5pm.
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trying using a renovating plaster/dri-coat etc next time marra.....its more expensive but its a better product
 
Two coats, same day, with good amount of waterproofer, devil up, 2-5 days to let it shrink and cure, then skim.

Skimming over internal rendering is a dream.
 
irish_spread said:
It's caused by the fairy juice the magician Dpc people inject in the walls . When they take the magic injection lances out of the wall, some of the fairy juice spills on the bricks and your s+c won't stick to it
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a think its silicon based stuff they inject.aye it wud cos it 2 slide.
 
we usually scratch and top the same day if poss but reason its sliding is the chemical damp proof course they have injected makes the bricks it is drilled into have no suction makes them like glass lol
 
i topped of the rest of the walls today and kept it tighter than the other walls and had no problems with it sliding but all the walls were on for 10am and were still pretty soft at 4.30! i think its just one of those thats had lots of bodge jobs done over the years as the last time it was dpc'd they floated it out with one coat and floated to the floor plus the house has a piv ( anti condensation fan ) fitted in the loft and the house is f**king freezing.
 
ive fancied trying the dry coat but at £16 a bag i dont see how i could use it on a full dpc when a bulk bag of sand is only £47.
 
you've just gotta sell its plus points to the customers. its a better insulator than S&C which can result in cold spots causing condensation, Its got salt-inhibitors in it. has very little shrinkage and you can skim it after 24 hours..........where did you get £16 a bag from?? thats abit steep
 
my local tp said £14 + vat artisan. and i believe it is a better product than s&c but all my dpc's are in rentals and go through 2 subbys who put there wedge on my costs so need to keep as keen as poss so we all make money!
 
brimplas1 said:
my local tp said £14 + vat artisan. and i believe it is a better product than s&c but all my dpc's are in rentals and go through 2 subbys who put there wedge on my costs so need to keep as keen as poss so we all make money!
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i hear ya marra...........:RpS_thumbdn:........everyone wants a slice dont they
 
Dri-coat is some dusty gear lol we done all the flood work in hull with that and came home with lungs of iron. Horrible to use and expensive but good for dubbing out and throwing on.
 
Has anyone tried adding vermiculite to the mix? A builder got me to try it in his garage where he has his central heating furnace. Made the mix nice to work with and adds insulation. Just a thought.
 
Rhys said:
Has anyone tried adding vermiculite to the mix? A builder got me to try it in his garage where he has his central heating furnace. Made the mix nice to work with and adds insulation. Just a thought.
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Vermiculite now there,s a name from the past did,nt know they still made that!
 
its the stuff in the bonding:RpS_wink: the stuff that floats at the top of the wash bucket
 
You can still get it in builders merchents. Gardeners use it as well to aid drainage.
 
jrplastering said:
i cnt for the life of me remember the name of the stuff thats in hardwall
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PERLITE!!!!!!! i was just sitting here not even thinking about it watching me kids dancing to christmas songs and it sprang into my head there you go artisan bonding has vermiculite in it and hardwall has perlite
 
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