Plastering advice

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Greenwoods
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Joined: Sat 12th Jan, 2019 12:28 am

Plastering advice

Post by Greenwoods » Mon 30th Nov, 2020 10:18 pm

I posted on here a while ago about sorting a dodgy conservatory extension done without any proper support.

We're now finally getting somewhere, having put in a steel "Goal post" on padstones, digging out the rubbish concrete over limecrete floor and installing new suspended floor.

I'm going with plasterboard and battens on the party wall with neighbour, but would like thoughts on what to do with the return/outer kitchen wall.

I've been thinking something like Adaptavate to keep it simple for the builder, but wondered if a plasterboard and battens would do for this wall as well.

Suggesting this to the builder as a possibility, he's worried me by saying we could do this and do a vapour control membrane on the outside of the wall. When the mess of lime plaster, gypsum plaster and concrete was removed, he has said the wall had a lot of moisture, but I'm thinking this is relatively normal in a 1904 Victorian a style house and the lime plaster will help this wall to breathe.

I was hoping battens and plaster board might also let the wall breathe, but now I'm thinking to get the Adaptavate in...

If you're doing a fitted kitchen with splashbacks/tiles/etc, does the room need to be as breathable as others when all the walls are pretty much covered in some way anyway?

MatthewC
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Re: Plastering advice

Post by MatthewC » Wed 2nd Dec, 2020 3:37 pm

I'd not heard of Adaptavate but their website claims that their Breathaboard is (as you might guess from the name) breathable. I still wouldn't use it on a listed building, but its use certainly sounds a better bet than plasterboard and battens! NB Is it susceptible to damp at all - would an undetected leak cause it to go soggy?

As regards the kitchen, I had the same thought with both the kitchen and bathroom when I did my house. I decided that, so long as the outside wall was properly pointed and kept dry then tiling the inside didn't matter. If though the outside was badly looked after with plants/high ground level/leaking RWG etc then I would need to fix those. Which I did. And it's all fine, nine years later... But you still need to ventilate the kitchen properly!

Matthew

Greenwoods
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Joined: Sat 12th Jan, 2019 12:28 am

Re: Plastering advice

Post by Greenwoods » Fri 4th Dec, 2020 9:50 pm

Thanks Matthew for reply - now likely going with a cement, sand and lime mix with plasterboard over the top - it's not a damp wall and well above the ground. We've also fitted air bricks in that wall now, with a suspended floor, which will be an improvement I think (and should help the flow of air throughout the whole house as well, from front to back).

TheForge
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Re: Plastering advice

Post by TheForge » Sat 5th Dec, 2020 10:14 pm

This is not a good idea. Any mix with cement in is a cement mortar. Lime plaster will be best suited and that will be a simple lime and sand mix with fibre in the base coat.

MatthewC
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Re: Plastering advice

Post by MatthewC » Sun 6th Dec, 2020 4:06 pm

TheForge wrote:
Sat 5th Dec, 2020 10:14 pm
This is not a good idea. Any mix with cement in is a cement mortar. Lime plaster will be best suited and that will be a simple lime and sand mix with fibre in the base coat.
Absolutely agree. Many builder will "add a bit of lime" (just to keep you happy, they think to themselves). By this they often mean hydrated lime, which only helps their mix as it makes it easier to work. It does nothing to help breathability.

You say in the first post that the 1904 house has a lot of damp in the wall which you think is "normal" for such a house.

NO!

It's only normal because people have messed up the old house (almost certainly built with lime) by using cementatious products (cement mortar or rendering, pink plaster, plasterboard, vinyl paint...), all of which keep the moisture (often due to broken or blocked RWG) in, whereas the old lime mortar allowed the dampness to get out, hence a dry wall. This is all the more reason to treat it seriously and avoid modern solutions and techniques.

See my blog (Click contact thing on the right, then click the blue blob) for the story of my house in 2010-2012 - it is warm and completely dry (and has been since I did all that work).

Matthew

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