Dealing with rain penetration in old house

MegamanBoo

I'm living in an old stone house which has limestone walls, approx 2.5 feet thick. These were rendered with sand/cement, I think in the early 80's.

Some of the walls seem to be taking in a bit of rain driven moisture. From what I've read I have three options.

1. Paint on a breathable water repellent over existing render.
2. Strip back render and re-render with new sand/cement which has a breathable waterproofing added.
3. Strip back render and re-render with a lime based plaster.

Anybody have any experience with these options? A friend had the lime based plaster done on a similar house and it did a great job but I believe it's very expensive.

Calahonda52

IFF you are certain it is rain driven, and not rising damp or what ever we are allowed all it these days, consider a cement board based rain shield, with a ventilated gap between it and the existing walls.
I see from your other post that your nearest neighbour is ...km away so no visual issues
It can be rendered over, with a mesh backing.

MegamanBoo

Calahonda52 wrote: »

IFF you are certain it is rain driven, and not rising damp or what ever we are allowed all it these days, consider a cement board based rain shield...

Hadn't thought of that, thanks.

I'm fairly sure it's rain driven, is there a way to tell for certain?

Calahonda52

MegamanBoo wrote: »

Hadn't thought of that, thanks.

I'm fairly sure it's rain driven, is there a way to tell for certain?

Not without a lot of $ being spent.
Have you french drains all the way around the house?

MegamanBoo

Calahonda52 wrote: »

Not without a lot of $ being spent.
Have you french drains all the way around the house?

No but the damp can be quite high up on the walls without being lower. Also we're on top of a hill with good drainage.

BryanF

1. Applying breathable paint to an non porous sand/cement makes no seems
2. As per 1
3. Is great in theory, definitely an option, but I’d be checking the details at gable ends/eaves etc before doing anything other than painting the house.

MegamanBoo

BryanF wrote: »

1. Applying breathable paint to an non porous sand/cement makes no seems
2. As per 1

Surely any unmodified cement product will be some degree porous. The idea behind these products is that they encourage beading water away but still allow the render to dry when water does penetrate.

It's solid in theory I just don't know how effective it would be.

Calahonda52

MegamanBoo wrote: »

Surely any unmodified cement product will be some degree porous. The idea behind these products is that they encourage beading water away but still allow the render to dry when water does penetrate.

It's solid in theory I just don't know how effective it would be.

Not entirely when u need consider the concept of solar drive, google it.
.
This is another reason why the cement board rain shed is such a winner

BryanF

MegamanBoo wrote: »

Surely any unmodified cement product will be some degree porous. The idea behind these products is that they encourage beading water away but still allow the render to dry when water does penetrate.

It's solid in theory I just don't know how effective it would be.

Cementitious products by their nature are not considered porous in the context of your original post. Putting breathable paint on cement render is a waste of money.

Yellow_Fern

can you describe the dampness in a lot of detail? Could it be a broken gutter that is leaking or condensation? Is the ground in your house ever below the ground outside the house? A lot can be done on a DIY basis, making sure the ground outside is lower and installing a french drain with gravel etc. Sometimes you might need to spend any money.

Metric Tensor

I think you should investigate your roof and it's junction with the wall first.

It would take more evidence than what you've described to make me certain that it's wind driven rain ingress.

Kincora2017

Firstly I think this is a situation where you need to get professional advice, a builder with conservation experience or a conservation architect. Getting the right advise will be the best money you will spend on this. You’ll need a site visit and a report & scope of works prepared for you - you may then be able to do some of the work yourself or retain the services of a builder.

In relation to you points, 1 & 2 make no sense as outlined by BryanF. Cement render on rubble wall will always cause trouble so even if you plan on cladding it in something totally different it really should come off first or all your doing is hiding th problem.

MegamanBoo

Thanks everyone for the posts. I think for now I'll take this on in stages, starting with a new roof which needs to be done anyway.

Down the line if I do go with a cement board cladding, is it very expensive? How are the boards attached to the existing wall? Is it something for a competent Diyer?

Would this cement cladding improve the warmth of the house? Does having the stone/rubble wall dry improve heat retention significantly?

Yellow_Fern

MegamanBoo wrote: »

Thanks everyone for the posts. I think for now I'll take this on in stages, starting with a new roof which needs to be done anyway.

Down the line if I do go with a cement board cladding, is it very expensive? How are the boards attached to the existing wall? Is it something for a competent Diyer?

Would this cement cladding improve the warmth of the house? Does having the stone/rubble wall dry improve heat retention significantly?

No expert but a dry wall is a decent but warmer. Cement cladding adds very little to insulation value. Lime hemp/cork render would, but not as much as other systems.

Kincora2017

MegamanBoo wrote: »

Thanks everyone for the posts. I think for now I'll take this on in stages, starting with a new roof which needs to be done anyway.

Down the line if I do go with a cement board cladding, is it very expensive? How are the boards attached to the existing wall? Is it something for a competent Diyer?

Would this cement cladding improve the warmth of the house? Does having the stone/rubble wall dry improve heat retention significantly?

If you’re not going to get a professional with conservation experience on board, starting with the roof & down pipes is probablu a good idea. Next after that, sort out ventilation within the building. That might be enough - remember old buildings need to breathe, so be very careful in introducing modern materials. The cement render is a case in point in this - it is stopping the house breathing and giving you issues with dampness. If you don’t want to tackle the render, improving the ventilation in the house might do the trick. This is where getting advise & a report will ultimately save you money in the long run.

In relation to the cladding, it is important to remember there is no guarantee that cladding this building will dry out your walls. Moisture exists in liquid and vapour form, so stopping water getting in in the form of liquid does not necessarily stop it moving through the building as a vapour. I hope that makes sense!
Best of luck with it!

MegamanBoo

Kincora2017 wrote: »

If you’re not going to get a professional with conservation experience on board, starting with the roof & down pipes is probablu a good idea. Next after that, sort out ventilation within the building.

Thanks, I will bring a professional onboard down the line. For now I can't take on any major changes so I'm focusing on what needs to be done and what I can do. I fully recognise the value of experience in this area.

Kincora2017 wrote: »

In relation to the cladding, it is important to remember there is no guarantee that cladding this building will dry out your walls. Moisture exists in liquid and vapour form, so stopping water getting in in the form of liquid does not necessarily stop it moving through the building as a vapour. I hope that makes sense!
Best of luck with it!

Makes sense alright, I've already introduced extraction fans which I found made a big difference. Some of the bedrooms still seem to suffer from condensation. Are there clever ways of bringing in some fresh air without letting the cold in?

Yellow_Fern

MegamanBoo wrote: »

Thanks, I will bring a professional onboard down the line. For now I can't take on any major changes so I'm focusing on what needs to be done and what I can do. I fully recognise the value of experience in this area.



Makes sense alright, I've already introduced extraction fans which I found made a big difference. Some of the bedrooms still seem to suffer from condensation. Are there clever ways of bringing in some fresh air without letting the cold in?

Yes, vents that only open when you have high humidity, or even better decentralised heat recovery. Expensive but a huge advantage in my opinion. Even on the coldest days you will have no issues getting the air fresh. You might need to watch out for noisy models though.