Plasterboarding over stone walls

[Dan20v]

Hi new to this forum
I am reneventing a old 300 year old welsh stone house
We have completely gutted the downstairs
All the walls are in bad shape someone in past has rendered the walls the walls were dot and dab before but I had damp was told the walls were not breathing ?
What my plan is to do is batten all the walls then insulate and the foil back plasterboard

What my questions are
What type of insulation do I need have been looking at wood fibre
I was told the wall has got to breathe ?
Should I put dpc behind battens ?
Should a add a vapour barrier ?
What is the best method to fix battens to to wall I was going to use 120mm concrete screws ?
Should I damp proof walls ? since I took old plasterboard off walls seem bone dry

Thanks all

[arco_iris]

I can't answer ALL of your questions, but I can comment with some experience as my Grade II Listed welsh cottage is at least 250 years old.

Yes that's correct, the walls need to "breathe", unfortunately many people (including so-called builders) don't understand this need, so that in the past all sorts of incorrect attempts were made to combat the issues.

Other things need to be investigated:

What is the outside like? If bare stone, are the gaps between rocks filled with a soft crumbly material (original), sand & cement mortar (totally incorrect but very often seen, in future, 'tibvos') or a very hard pointing (modern hydraulic lime mortar). If it is painted, is that lime wash (creamy-white-ish), or masonry paint (tibvos).

What is the internal render? Should be bare stone or LIME plaster, not sand & cement render or gypsum plaster both of which are tibvos.

What is the floor (and skirting board if any) like? Where signs of damp, are these signs all the way to the floor and into it? (Any sign - a row of drill holes about 8" up - of chemical dpc being installed? Tibvos).

What is the ceiling like? I'm going to suggest (but don't quote me, this forum is a collection of opinions only) putting a beam on the floor (over dpc but not screwed down), a beam across the ceiling (which could be fixed, if ceiling has timber joists), then wedging the vertical studs between these two horizontal plates. In this way, studs are not screwed to the wall (the screws may eventually corrode) so no transmission of damp. As for insulation (which never existed 250 years ago) I would cut PIR panels wedged between the studs & noggins, then plasterboard over the top.

Stopping there for now.

[Dan20v]

The outside of the house has been all cement rendered over the stone about 20 years ago
The internal walls are cement render and then been skimmed with gypsum and we're dot dab but removed the old plasterboard now
When I took the skirting out there was signs of rot but they were bone dry . the floor has had dpm put down
The ceiling was good no signs of damp
And yes about 20 years ago there has been chemical in just one of the walls

[arco_iris]

Hmmmmm......

And how far do you intend to go, and to what end? You don't have to answer, these "questions" are to keep you thinking & for my own imagination:

Money no object, it takes what it takes, or tight budget?
Day job or retired, time to devote?
DIY skills (or a practical bent, willing to learn) - or employ contractors?

Which county?
Rural, village, or town?
Detached, semi-detached or terrace?

I've had & rectified, or still have to deal with, all the issues you mention, five years so far, on & off:

20210622_154602.jpg (298.37 KiB) Viewed 6580 times

[Dan20v]

Well basically I just want to do it right am currently working and doing almost all the work my self afterwork and weekends
My job is a auto electrician
We are in smal rural town in Carmarthenshire the house is detached used to be a old farm house

[arco_iris]

My job is a auto electrician

Didn't need to know that! Know anything about replacing the capacitors in a 30 year old instrument cluster control module?

I'm near Pembroke Dock if you're over this way.

Do it as right as you can, it doesn't cost a lot, just time-consuming. Worth that though, to be maintaining the fabric of an old building can be very gratifying, especially correcting previous bodges.

[wes56]

First things first:

Remove all render and plaster back to stone on the outside of the building and the inside.
Hack out all pointing on the outside and on the inside of the building to a depth of about 20mm - 25mm.
Then take photos of inside and outside and post them on here.

Use sand and lime render on the inside and the outside if you want traditional pointing and render that actually works.

[schakal]

Amazing cottage in the photo
Just out of interest where do you guys find these kind of properties in Wales ? Is there a specialist site apart from the usual rightmove ,zoopla etc?
Very interested in a barn / cottage that needs work as a retirement project myself

[arco_iris]

schakal!

Just out of interest where do you guys find these kind of properties in Wales ? Is there a specialist site apart from the usual rightmove ,zoopla etc?

Not that I know of - just keep looking! The sites you mention are probably good as any.

Didn't set out to buy this, just knew the area wanted, signed up with several local agents, waited for the right property to be offered. Two acres, large garage & indoor pool in a detached annex did it though, if only we'd realised the work that would be involved......

[schakal]

schakal!

Just out of interest where do you guys find these kind of properties in Wales ? Is there a specialist site apart from the usual rightmove ,zoopla etc?

Not that I know of - just keep looking! The sites you mention are probably good as any.

Didn't set out to buy this, just knew the area wanted, signed up with several local agents, waited for the right property to be offered. Two acres, large garage & indoor pool in a detached annex did it though, if only we'd realised the work that would be involved......

you are very lucky to live in such property . good luck with all the work