Wall problems

[GinnyLong]

I have an old granite barn conversion. End of terrace. Can anyone advise on the best way to stop the mould growing & yellow salt marks coming through the walls please.
I have been keeping the windows open an inch all winter & treating the mould with chlorine bleach from HG, every time it appears.
I have painted over the yellow marks with Buxton Limewash but it’s coming through again.
The barn has solid ( no cavity) walls & no foundations or damp course that I can see. Any help would be appreciated. Thanks.

 

[stuart45]

Have you got any external photos?

 

[a twig]

Do you have any pictures of the exterior at the same location?

 

[a twig]

Ha jinx!

 

[GinnyLong]

Have you got any external photos?

Just uploading now

 

[stuart45]

Thanks for the photos. At a first glance, it does look like you have a lot of stuff keeping any sun off the bottom of the wall, which can hinder the wall drying out. Also worth standing outside when it's hammering down to see how the gutters are performing. I guess you have lime mortar in the joints.
The problem with solid walls is that with enough driving rain eventually it will find it's way through. How thick are the walls?
Having flush eaves doesn't offer much protection to the walls as well.

 

[GinnyLong]

The metal gutters are working ok. However I am on top of a hill facing the sea. I would understand if it was just the exterior walls, but the wall adjoining next door is also doing the same. I wonder if a French drain would help. Is there anything I can coat the walls with that will allow them to breath but stop the problem?

 

[stuart45]

You need find out exactly what's causing the damp first. Rising, penetrating, condensation etc.

 

[GinnyLong]

Ok

 

[Lacan07]

The metal gutters are working ok. However I am on top of a hill facing the sea. I would understand if it was just the exterior walls, but the wall adjoining next door is also doing the same. I wonder if a French drain would help. Is there anything I can coat the walls with that will allow them to breath but stop the problem?

where about on the adjoining wall, does it occur all the way across?

I agree with Stuart you need to get to the bottom of the cause, rising damp is rare imho. I would only go down that route if had a high water table

 

[GinnyLong]

The survey when I bought it said rising damp only.
The staining goes all the way along the adjoining wall. Upstairs is a bit better than downstairs.

 

[GinnyLong]

It wasn’t as bad as this last year

 

[GinnyLong]

Looks like I’ll have to find a company that specialises in these old buildings.

 

[stuart45]

Rising damp is more complicated to diagnose properly, so a surveyor wouldn't be able to really know in the short time they allow for a survey. We have had the wettest February for 200 years, and if you are on top of a hill in an exposed position near the coast there's a good chance that the rain has got through the walls.
Using a sealer is really a last resort. Silane Siloxane is said to be breathable, although breathable could be anything from allowing a small amount of air to pass through to a large amount.

 

[GinnyLong]

That makes sense. I think I will have to wait for them to dry out . Maybe the pointing needs looking at.

 

[stuart45]

There looks like there's a few gaps in the joints near the bottom by the door.

 

[a twig]

Is it a concrete floor or a wooden suspended one?

 

[GinnyLong]

A mix of laminate & huge slate with under floor heating. Don’t know if there is concrete under the laminate

 

[a twig]

I’d agree with Stuart re: wetness, saw an article the other week that 1st March 23 - end of Feb 24 was the wettest 12 months period on record since 1871 so a lot of older buildings are being pushed to their design limits in trying to cope with it.

Looking at your photo with the window and door, for me the interesting bit is the right hand side where the top half appears to be wetter than the bottom half which would seem to indicate water coming from above rather than below potentially being the main culprit.

Also the window ledge seems to be wetter underneath, so worth checking that the ledge is sloped away from the house rather than back towards the window.

A visual inspection of all the caulks and sealants around the windows may also throw up a few holes where water can get in.

In terms of mitigating the sea winds, planting a hardy hedge a few metres in front of the wall may help give the walls some protection from driving rain

 

[GinnyLong]

Ok, thankyou