Dri coat over Gypsum

[supertrowel]

Hi guys
Starting a job tomorrow where browning has been hacked off 1mtr high due to flood damage. it has dried out and Ive been asked to float over with dri coat as the customer wants some thing more than hardwall to replace. It does say on the dricoat bag NOT to use over residues of gypsum, however there are 20% residues of gypsum left.

Can i use any thing to seal the residues of gypsum then use dri coat or is this a no go?
Any advice would be appricated

cheers

 

[twitcher]

I've used an sbr cement slurry like this before.

 

[Render Systems]

do the job properly mate 2 x sand and cement render 5 sand 1 cement 1st coat add freeflow... second coat 6 sand 1 cement... top off with multifinish

 

[henry]

That di coat is good gear just get your walls clean .

 

[supertrowel]

i thought id use dri coat as i was advised S and C would blow with gypsum underneath.

would a pva seal help before applying dri coat ?????

 

[henry]

you have to take the gypsum off a pain I know.

 

[rockhardsolidplastering]

get a good razor scraper and get yer back into scraping it off .pva is a no no .dri coat is good gear but it needs to be gypsum free

 

[henry]

That's all I use internal works now rocksolid ,that and renderlite I leave it for 48 hours to dry suction over when possible on dpc work.Have you picked anymore work up yet?,

 

[spunky]

What's freeflow render?

 

[henry]

just trying to think bubbles told me about this stuff spunk now what did he tell me?

 

[S a plastering]

What's freeflow render?

freeflow is just the addy i think mate

 

[rockhardsolidplastering]

henry not yet mate altho some positive leads hopefully will come to fruition

 

[spunky]

Is it like sbr

 

[supertrowel]

so why cant you dri coat over gypsum resides then ?

 

[henry]

so why cant you dri coat over gypsum resides then
It holds moisture mate there is only one way that is the right way.

 

[supertrowel]

So what would be ok to use over gypsum residues on block work ?

Hardwall ?

 

[spunky]

Krend

 

[twitcher]

hardwall's gypsum based innit, so should be fine

 

[henry]

I feel your pain mate I bet it's a right t**t to get off . How high up the wall is the hardwall ?

 

[supertrowel]

it a mtr heigh mate

A mtr too heigh

So my options are take off all existing browning and use dri coat

or

wait until the walls completely dry out and use hardwall

 

[rockhardsolidplastering]

I WOULD NT TAKE THE CHANCE WITH A GYPSUM BASED PLASTER NOW THAT ITS HAD BAD WATER DAMAGE oops caps it wont be hard to get off with the right tool and some grease for yer elbows

 

[supertrowel]

Thats it then il go and get my scraper out the shed

Nice one lads

Thanks for your advise

 

[flynnyman]

Is the wall still wet?

 

[henry]

Ive seen were chasing have been made up around skirting height in old terrace housing with drywall, and after a time it just bubbles the plaster..
If your putting a gun to my head then mix sbr & cement slurry and paint the wall, your call.

 

[supertrowel]

no the walls have dried out now

 

[martinemj]

dricoat is a renovating plaster like limelite ----a 1:1:6 lime/cement/lime mix lime products should not come into contact with gypsum (difficult not to)due to a reaction...

bg say to skim over dricoat with multi finish but i prefer to stick with high impact finish ----

best to hack it off mate .....




e&m jenkins plasterers & builders,plastering,gloucestershire

 

[a.d.plastering]

do the job properly mate 2 x sand and cement render 5 sand 1 cement 1st coat add freeflow... second coat 6 sand 1 cement... top off with multifinish

eeer no dri coat is better than s/c based render it was designed to 4 the job i acts as a vapour barrier to alow the walls to dry out but stop the passege of water & htdroscopice salts s/c renders dont let walls dry out :-0

 

[a.d.plastering]

i now its going to be a pain but it needs to be done properly i did one not so long back you need to get the walls clean i think the reason why dri coat cant go over gypsum is because the gypsum acts as a barrier & stops the dri coat from doing its job vapour barrier ( get the idea ) :RpS_thumbup:

 

[Chris W]

a vapour barrier stops the passage of airborne moisture e.g. water VAPOUR... e.g. a plastic sheet between plasterboard and porous insulation over a cold surface, such as a single skin wall or a cold roof...
something that allows water vapour to pass through whilst holding back liquid water is known as 'breathable', e.g. tyveck roofing felt etc...
there may be a confusion of terms going on here...

p.s. isnt dricoat basically sand cement and possibly lime with added waterproofer and salt neutraliser (vinegar) in the same way multicem is basically opc with added plasticiser?

 

[a.d.plastering]

thats whay is said on the bag when i used it vapour barrier

 

[martinemj]

a vapour barrier stops the passage of airborne moisture e.g. water VAPOUR... e.g. a plastic sheet between plasterboard and porous insulation over a cold surface, such as a single skin wall or a cold roof...
something that allows water vapour to pass through whilst holding back liquid water is known as 'breathable', e.g. tyveck roofing felt etc...
there may be a confusion of terms going on here...

p.s. isnt dricoat basically sand cement and possibly lime with added waterproofer and salt neutraliser (vinegar) in the same way multicem is basically opc with added plasticiser?

yes it 6:1:1 sand /cement/lime with additives(same as limelite)

 

[twitcher]

WTF are the little hairs innit though? It's not the nicest stuff to lay on either.

 

[martinemj]

yes it has fibres in it... i reckon its great stuff to lay on myself ----





e&m jenkins plasterers & builders,plastering,gloucestershire

 

[henry]

dri coat and renderlite are the dogs with the big b*ll***s

 

[Chris W]

has it got any pearlite in it or just 6:1:1 with fibres and good consistent sand?
just strikes me a 12 quid for 25kg of stuff you could make yourself as long as you use good sand and guage the mix properly...
not hard to get hold of fibres.... not heard fibres mentioned on here for a good while actually, prolly since everythings been about the pre-bagged stuff these days...