Bonding over sand and cement render.

Jda plastering

New Member
Hi everyone,
I'm fairly new to plastering (I'm good at that bit ) a customer had damp issues so I've removed the plaster boards from the ground up to 40cm all round. Sand and cement rendered the walls that have been treated with a form of damp proofing and cavity repair. The customer specifically asked me to render out to the depth of the boards (which were dabbed on by someone else and the dabs are about 3" thick!) I've done 2 coats of render already and still got 12.5mm to go, rather than adding another coat of render can I use thistle bonding coat on it instead and then rule it off level with the existing wall? The render was done 24hours ago.

Thanks
 

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algeeman

It’s A Boy
Hi everyone,
I'm fairly new to plastering (I'm good at that bit ) a customer had damp issues so I've removed the plaster boards from the ground up to 40cm all round. Sand and cement rendered the walls that have been treated with a form of damp proofing and cavity repair. The customer specifically asked me to render out to the depth of the boards (which were dabbed on by someone else and the dabs are about 3" thick!) I've done 2 coats of render already and still got 12.5mm to go, rather than adding another coat of render can I use thistle bonding coat on it instead and then rule it off level with the existing wall? The render was done 24hours ago.

Thanks
download.jpg
 

carl-the-plasterer

Well-Known Member
Thistle Dri-coat?

You'll need to key that second coat of sand & cement though.

Wouldn't surprise me if you'll get someone suggest dot & dab 9.5 mm plasterboard onto the cement to bring it level also......but I wouldn't personally.
 

beader

Private Member
Hi everyone,
I'm fairly new to plastering (I'm good at that bit ) a customer had damp issues so I've removed the plaster boards from the ground up to 40cm all round. Sand and cement rendered the walls that have been treated with a form of damp proofing and cavity repair. The customer specifically asked me to render out to the depth of the boards (which were dabbed on by someone else and the dabs are about 3" thick!) I've done 2 coats of render already and still got 12.5mm to go, rather than adding another coat of render can I use thistle bonding coat on it instead and then rule it off level with the existing wall? The render was done 24hours ago.

Thanks
What is causing the damp issue?
 

Jda plastering

New Member
No idea mate I've just been asked to skim the boards and he's selling the property... Doing as I was asked. Think the damp coarse has had it to be honest and he floor is letting damp through sone places. I suggested he sort the floor out and the damp corse but he refused the idea. I bonded it in the end it stuck OK and looks fine for now... Was going to dot n dab board on another area to see if it worked. I scratched both coats of render as I intended to add another lay of render however it still wouldn't have met the boards. Thanks for your advice
 

carl-the-plasterer

Well-Known Member
No idea mate I've just been asked to skim the boards and he's selling the property... Doing as I was asked. Think the damp coarse has had it to be honest and he floor is letting damp through sone places. I suggested he sort the floor out and the damp corse but he refused the idea. I bonded it in the end it stuck OK and looks fine for now... Was going to dot n dab board on another area to see if it worked. I scratched both coats of render as I intended to add another lay of render however it still wouldn't have met the boards. Thanks for your advice

Why didn't you back the remaining area out with Thistle Dri-coat,especially if damp course is a bit dodgy?

worst thing you can do is put gypsum based backing on a damp wall..........but being a 'plasterer' you should know this.
 

Jda plastering

New Member
I used bonding coat on one patch and dot n dabbed another. I can plaster and all my walls r flat and as close to perfect as possible, haven't had experience with all backing plaster only hardwall and bonding coat so ever so sorry to disappoint
Why didn't you back the remaining area out with Thistle Dri-coat,especially if damp course is a bit dodgy?

worst thing you can do is put gypsum based backing on a damp wall..........but being a 'plasterer' you should know this.
 
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