Undercoat plaster for chases with PVC oval conduit

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lsx

New Member
Hi

I've got a few chases above light switches in original victorian lime plastered walls to fill.

The chases look like the one shown in the photo... they're 75mm wide, 15mm deep and contain 2 bits of 25mm wide oval conduit side by side, clipped into the back of the chase. The top surface of the conduit sits flush - or about 1mm below - the top of the chase.

What I'm unsure of is will I have problems applying the backing coat on top of the conduit to a depth of approx 4mm if the 4mm isn't in the chase it's on top of it? I'm thinking that I should have chased the walls slightly deeper so the conduit would then sit 4/5mm from the top of the chase. I'm planning to use something like l*m*-g***n Grippa (Prep Bond Q) for my backing coat.

Sorry I haven't done a diagram. I'm rubbish at drawing.
 

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lsx

New Member
Why are you not using lime putty and sand? Just bed some jute scrim in over the conduit
I went to Womersleys and spoke to them about filling chases. They said lime putty / sand struggles to stick to PVC cables so I could bed the cables in Grippa then lime putty and sand over the top.

Should I try to push lime putty / sand into the sides of the chase and around the conduit or is there no advantage?

Thanks
 

Mouldyoldspudgun

Well-Known Member
I went to Womersleys and spoke to them about filling chases. They said lime putty / sand struggles to stick to PVC cables so I could bed the cables in Grippa then lime putty and sand over the top.

Should I try to push lime putty / sand into the sides of the chase and around the conduit or is there no advantage?

Thanks
Just push the lime and sand into the chase eachside of the conduit and bed the jute scrim into it bridging both conduits let it go off and fill the chase, the jute scrim will hold the putty and sand in place and keep it off the conduit
 
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