Penetrating damp

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blackbirdxx

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Hi,
I have a c1890’s house constructed with solid brick suffering from penetrating damp in the upstairs walls. With the bad weather we’ve had in the UK this winter, the problem has been worse than ever with damage to the internal decoration within predominantly the south facing walls. FYI there are no problems with the guttering or around windows and the tiled roof extends well proud of the walls giving maximum protection to rain getting in at the top. All the upstairs walls are roughcast rendered although I’m not sure if they are composed of lime or sand/cement. The walls are painted with magnolia Sandtex masonry paint. This damp problem has been going on for about 8 years now (ever since I bought the property) with each upstairs south facing walls having been re-rendered over the years with sand/cement up to top of window level.
My questions are:
I’m not sure what the existing upstairs render is, either lime or sand cement. Is there a way of finding out?
By replacing the lower patching render which was replaced appx 8 years ago with a breathable lime mix, will this address the damp problem, even if the rest of the render is sand/cement?
I understand I will need to lime wash the new lime render. Will I need to take the impermeable Sandtex paint off the rest of the house or can I over paint it with a lime wash so the whole house looks the same?

Thanks in advance any other tips you may have.
 
To enable the walls to 'breathe' both internal and external wall coverings need to be lime based render without cement as cement will seal one side or the other..

Also any vinyl or acrylic based paints will also seal the surface

To fully ensure the new system works as it should you should hack back to brick.

You could also put a stud wall insulated on the internal side of the walls which will be a much more coat effective way or sorting out the problem.

@seanlar @carlos
 
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blackbirdxx said:
Hi,
I have a c1890’s house constructed with solid brick suffering from penetrating damp in the upstairs walls. With the bad weather we’ve had in the UK this winter, the problem has been worse than ever with damage to the internal decoration within predominantly the south facing walls. FYI there are no problems with the guttering or around windows and the tiled roof extends well proud of the walls giving maximum protection to rain getting in at the top. All the upstairs walls are roughcast rendered although I’m not sure if they are composed of lime or sand/cement. The walls are painted with magnolia Sandtex masonry paint. This damp problem has been going on for about 8 years now (ever since I bought the property) with each upstairs south facing walls having been re-rendered over the years with sand/cement up to top of window level.
My questions are:
I’m not sure what the existing upstairs render is, either lime or sand cement. Is there a way of finding out?
By replacing the lower patching render which was replaced appx 8 years ago with a breathable lime mix, will this address the damp problem, even if the rest of the render is sand/cement?
I understand I will need to lime wash the new lime render. Will I need to take the impermeable Sandtex paint off the rest of the house or can I over paint it with a lime wash so the whole house looks the same?

Thanks in advance any other tips you may have.
Click to expand...
a lime render for your house indeed
 
Is the problem black mould???

If you do indeed have penetrating damp. My first question is how is the water getting through both the paint and render if they are both in good order???
 
Line it mate, problem gone ,the house can breath in and out to its heart content :rolleyes)
 
Guys, thanks for the feedback…..
Keith, when you say line it what are you suggesting, some sort of stud wall with insulation perhaps? A spec would be useful.
If lining is done are you suggesting that the current outside render is not tampered with? Also, wouldn’t mould grow at the interface of the lining and damp solid brick wall?

Any assistance appreciated.
 
Is it penetrating damp though? As Carlos asked and you didn't answer, is it black spots/mould?
That would indicate condensation due to a cold exterior wall and not penetrating damp. :RpS_thumbup:
 
Hi,
I’ve been told that its penetrating damp as opposed to condensation by a builder. There are black patches showing in some areas now, I thought because the damp has been there for so long. The walls still have damp patches her and there with no black spots, I thought because the damp can’t get back out through the sand/cement render. The builder could be wrong of course, although there's no condensation problem on the inside of the windows etc. I also fitted a vent in the wall which I hope has gone someway to address any condensation.
 
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