Dampness issue

[Davy C]

Hi,
I'm new to this forum and I originally posted the below in the plastering and rendering forum, however I think it's better suited to this section. Hope I've not broken any rules!

I'm having dampness issues at my mums house, the rear of the house is south facing and very exposed to the elements, with just fields behind the house (we are in Scotland). It's been a problem for a while, and gets worse when the heavy rain is battering against that wall of the house.

The internal wall is wet and the paint is flaking, the main problem areas are below the large window you can see on the ground floor, just to the left and right hand side. There is also a small damp patch just behind the air brick near the top of the back door. Some water is also coming in just above the small window on the ground floor and landing on the window ledge. It should be noted the windows are old and probably needing replaced sometime in the not too distant future.

Although I can see the render is cracked in some places, it doesn't seem to be cracked in the damp areas. It's probably also worth pointing out that the downpipe runs inside the wall, not sure if this could be causing an issue?
I have sealed up all the cracks on the ground floor with silicone, but this hasn't helped. We are not concerned about the cosmetics of the back of the house, we just want it water tight. Photos are attached below. Hopefully someone can shed some light?

Thank you

Read more: //www.diynot.com/diy/threads/water-ingress-through-render.452391/#ixzz3yxGR593e

 

[freddiemercurystwin]

Get the rwp external in the first instance,that's destined to fail. Otherwise if that doesn't do it a re-render will probably do it. Sealing up cracks is only ever gonna be temporary anyway, even if it had worked. What's the roof like? Cavity wall presumably?

 

[Davy C]

Thanks for the reply. So you think I should have the down pipe routed externally, and if that doesn't help then get the whole rear of the house re-rendered? I'm not sure what route the pipe takes inside the wall, but I thought this was unlikely to be the problem, as the damp patches are so far away from each other.

Not sure what the roof is like, not even had the gutters checked yet, but my mum hasn't noticed any overflow from the gutter.

Yes, it's a cavity wall.

 

[freddiemercurystwin]

An internal rwp is plain barmy especially a bit of plastic that's as old as I am and not designed for the job. It could be leaking like a sieve! Whoever routed it inside wants shooting, prolly the original developers.

 

[wessex101]

The external render looks damp around the ends of the window sills which suggests they are not shedding the rainwater correctly, this also corresponds with the internal damp marks. Take a closer look at them and see if the water is ponding or running back towards the window and soaking into the wall.

 

[Davy C]

An internal rwp is plain barmy especially a bit of plastic that's as old as I am and not designed for the job. It could be leaking like a sieve! Whoever routed it inside wants shooting, prolly the original developers.

Yeah I believe all the houses in the street were built with the internal rain water pipe

 

[Davy C]

The external render looks damp around the ends of the window sills which suggests they are not shedding the rainwater correctly, this also corresponds with the internal damp marks. Take a closer look at them and see if the water is ponding or running back towards the window and soaking into the wall.

Thanks for the reply. Yeah both ends of the window ledge seems to be the issue. I did notice a little moss growth in the drainage gap between the window frame and sill (in the right corner). What things should I be looking out for here? I've no experience in this field. Cheers

 

[^woody^]

That second image of plaster seems to show a damp line which corresponds to that crack under the first floor window.

Some of those other render cracks look structural too

 

[wessex101]

Looking at the ground floor photo it looks like the sill bows up in the middle so all the rainwater would be pushed to the ends. If that is the case make sure any gaps are well sealed to stop the water soaking into the walls. Ideally the sill should throw the water clear, like a waterfall across the full width of the window but to achieve that you would have to take the windows out and re-bed the sill so not really worth the disruption.

As others have said the cracking in the render (harling) and internal rainwater pipe are also potential sources of damp that will need sorting out.

 

[Davy C]

Thanks for the replies. I'm aware the Roughcasting, rainwater pipe and Windows will all need renewed in due course.

I'm glad the bow in the sill has been flagged up, this is something I hadn't noticed. The mastic all around this window and sill doesn't look too clever, so I think the first plan of action will be to have that full area re-sealed with silicone tomorrow and take it from there. Fingers crossed.

 

[Jdntg]

Hi Davy C, apologies for replying on this old thread but I’m having the exact same issue as you posted here. Just wondering if you managed to solve it and if so, could you share the solution please?
Thanks