lime rendering costs

[jason61c]

I'm about to embark on a project house. Its cement rendered and its got to come off, it needs lime render putting on.

I'm thinking about learning how to do it myself, however does anyone have a ballpark price per sq m if I had someone do it?

 

[joe-90]

Why does it have to come off? Have you been reading that silly eco stuff?

 

[jason61c]

It has to come off as the house has solid walls, there's moisture trapped in the stone.

One gable end has lots of 'bubbles', the lower part of the house just needs the cement removing to reveal the stone to help the house to breathe.

What eco stuff are you talking about?

 

[joe-90]

Damp issues are never sorted by removing render. Modern lifestyle with central heating is way too humid for that to work.

 

[jason61c]

Damp issues are never sorted by removing render. Modern lifestyle with central heating is way too humid for that to work.

What makes you say that? The house isn't centrally heated(yet).

 

[joe-90]

The heat in a modern house draws moisture up from the floor which passes into the wall and condenses as damp. It's called interstitial condensation. It's amazing how many surveyors know nothing about it.

 

[jason61c]

The heat in a modern house draws moisture up from the floor which passes into the wall and condenses as damp. It's called interstitial condensation. It's amazing how many surveyors know nothing about it.

So how does it get out of a wall if it can't breathe? This isn't a modern house its a 3-400 year old house.

 

[joe-90]

There's too much to get it out of the house. You have to stop it getting into the wall.

 

[jason61c]

just to give some further info, I had a specialist round who knows his onions...

http://www.exposuresurveying.co.uk/

Hes pretty awesome, a lovely £10000 drill that drills 2mm holes into timber beams measuring how thick they are, how damp, any holes/rot etc, great bit of kit.

Unlike the complete idiot who said it needed a chemical damp proof course

You think cement render isn't an issue?

 

[jason61c]

There's too much to get it out of the house. You have to stop it getting into the wall.

how would you stop it getting into the wall?

 

[joe-90]

You need to talk to a local old boy builder. You either replicate the old way and have big chimney breasts, open hearths, and cooler rooms or go the modern route and use vapour barriers. Only someone who can see the house and knows what they are talking about can advise you.

 

[jason61c]

You need to talk to a local old boy builder. You either replicate the old way and have big chimney breasts, open hearths, and cooler rooms or go the modern route and use vapour barriers. Only someone who can see the house and knows what they are talking about can advise you.

Thats what I've had. 'vapour' barriers would surely just trap moisture in the wall causing it to eventually fail? The cement render would eventually fail also due to moisture underneath?

 

[RogueHanger]

I would have thought, but I'm no expert, that a 3-400 year old house will not have any DPC, therefore moisture can and will travel up from the ground.
And as Jason, suggests, DPM on either side of the wall will leave it trapped in the wall.

I have stone built walls, with a cob like mortar. I've pointed outside with a cement/lime/sand mixture, and inside, the lower 900mm of the ground floor I've used a cement/fine sand render with a damp proof liquid in the mix. (Normal sharp sand 0-2mm comes in bags here, otherwise it's 0-4mm)
I've used lime plaster internally then, on all stone walls. It's important to use a breathable paint, such as lime wash on breathable plaster.

But then again, I have a wood burner also, which I suppose moves a fair amount of air when it's lit.

If I were you I'd post your query in the building forum on here, and do plenty of research on t'internet, especially historical and traditional type building renovation web sites.

BTW, I invested in a compressor (About 100litres with twin cylinders) and a render gun for the plaster. messy but a lot quicker and easier.

 

[joe-90]

You need to talk to a local old boy builder. You either replicate the old way and have big chimney breasts, open hearths, and cooler rooms or go the modern route and use vapour barriers. Only someone who can see the house and knows what they are talking about can advise you.

Thats what I've had. 'vapour' barriers would surely just trap moisture in the wall causing it to eventually fail? The cement render would eventually fail also due to moisture underneath?

You have two choices. Go the old route and ventilate or go the new route and create a damp free environment inside the house. No-one on here can tell you which is best as they can't see your situation.

 

[AronSearle]

Thats what I've had. 'vapour' barriers would surely just trap moisture in the wall causing it to eventually fail? The cement render would eventually fail also due to moisture underneath?

Most of the moisture is likely coming from the internal enviroment, a VCL on the warm face, or even vapour proof paint, "may" fix the issue.

Your rendar will be more breathable than the vapour barrier, it's not impermable. It may be at the moment it is the most vapour resistant part of the construction, so water vapour passing through the wall is hitting the back (cold) face of the rendar.

Normally maintaining a 5:1 ratio of breathability solves this issue (a VCL being 5x more vapour resistant than the rendar).

Do some reading on this, you can also download free condensation risk anylisis programes that you can test any hypothetical wall buildup on.

If you do go down the route of VCL's, they have to be well fitted, and properly lapped/sealed around openings. Also be aware that without insulation the reduced air leakage will make condensation on internal surfaces more likely.