Filling wall chases for wiring

[simonjamesm1]

Hi,

We've had the wiring replaced in our 1800 (ish) red brick house. The walls are lime plastered and we chased through the lime into the brick, which was actually very neatly done apart from one chase where the bricks seems to break up (poor set of bricks). Has anyone had any experience of filling them in? I have had some advice saying just use 3 part cement, lime, sand mix, others say use a bonding agent to create a bond onto the wires then fill or use a filler then lime plaster over.

I am told that lime on its own will struggle to bond to the cables. The circuit protected by a 30mA RCD so there is no cable conduit, which I imagine would be even harder to get lime to bond to.

Any tips or advice would be great!

thanks

 

[Lime]

IME (I've done it 1000s of times) on lime plaster the best material to use to fill the chases is Polyfilla (interior).
It adheres well to the lime plaster and mortar, cable and brick and has much the same properties as lime.
It is best to do it in two stages.
1.
Wet the old lime plaster and fill the chase with polyfilla to just below the surface of the lime plaster and let it harden.
2.
Fill the remainder of the chase so the polyfilla is slightly proud of the lime plaster.
Lightly sand down (with a course paper No 40 -60) about an hour after it has hardened.
DON'T LEAVE IT to fully harden because it will be a lot more difficult to get it perfectly flat.

 

[Feltwell]

I'm with Lime but get yourself a bag of Gyproc Easifill from any builders merchants.

It's a powder filler that's meant for jointing bevel-edge plasterboard sheets when drylining - but it's also just a great general purpose filler. A bag of the stuff is fairly cheap, easy to mix, doesn't shrink much, and is dead easy to sand and get a good surface with. A bag last for ages, if you keep it inside a polythene sack then it will keep and be useable a long way past the best before date - only thing is when it starts to get really old (3+ years past it's date!) it goes off a bit quick after you've mixed it.

I've filled umpteen cable chases here with the stuff, works a treat. I'd use a finer paper than Lime does for this stuff. I tend to fill in one go, slightly proud of the surface, it's so easy to rub down it never takes long even if you leave it for a few days.

If you get yourself an Abranet kit and a Henry vacuum cleaner or similar, it's both incredibly easy to rub down (the abrasive won't clog) and it's virtually dust free. Great system. I use mine all the time, both for sanding wood and plaster filler.

https://www.restexpress.co.uk/acatalog/Mirka_Abranet_Professional_Starter_Kit_70x125.html#SID=12