What products to use for damp proofing and the process

[97browng]

Hello All,

I am looking to sort out a damp issue we have with one of our walls.We don't gets a huge amount of damp but there are a few patches that have come through. The house had has a DPC but I think this issue was caused by faulty guttering (which has now been repaired). I know it might well sort itself over time but as the wall is an exterior wall which gets rather wet anyway (I live in Wales) I thought I may as well get it sorted once and for all.

So this is what I had planned and I wanted to know your thoughts;

1 - Make sure any causes of damp are fixed (I will check guttering again etc...).
2 - Leave it dry for a bit (I will start in the summer).
3 - Clean external wall with pressure washer.
4 - Check for defects and repair any wall damage (there may be a few small cracks in render, which I will fill).
5 - Apply external waterproof coating and cover with exterior paint
6 - Internally clean wall and then apply a damp seal

Does this process sound ok to you? If so what products do you think I should use? I see that Stormdry masonry protection cream has good ratings, but is is a little expensive. I want to get something that does the job so if this is a good option then I will get it. I have also seen PermaSEAL Damp Proof Paint but I am not sure if this is what I want.

Then internally am I OK to just use something like ronseal or polycell damp seal? It looks like there is a little bit of efflorescence so should i just clean that or is there a specific treatment. As I said aove we are not talking about a large area.

Thanks in advance
Gary

[wes56]

post photos of the interior and the outside of the wall for a better anser.

[97browng]

Sorry for the delay. See the attached. The first one is the internal wall. As you can see it is only a very small section of wall that has damp.

The other two are external pictures. Its very hard to see the small cracks.

[wes56]

the render is showin stains and signs of previous repairs to the right of the red circle.lower down theres a crack runninig left to right.
the render should be cut back from touching the ground by about 50mm to 75mm or it will suck up damp.
theres green splash marks on the ground maybe from gutters or rain hitting pipes and bouncing out.
you need to go over the render lookin for blown areas or cracks.you wont know what areas are affected until youve closely looked.
dont pressure wash and i dont think water proofers always work proply. esp where its cracked or blown render.

inside the room do you have cavity walls or what looks like a solid wall?
just above the skirting theres shadow and marks. is any wallpaper loose. have a close look for damp.
when damp has penetrated or risen usuly you have to knock off the bad plaster and redo with render.dont redo with gypsum plaster
sealing it wont work.

[97browng]

Sorry for the delay in getting back.

The wall is a solid wall. The shadow and marks above the skirting are not damp they are just scuffs and a shadow from the plaster, in proper light there is nothing there. The lining paper on the top was coming off, which i have now stripped off.

I have been in the house for 8 years and its only in the last few months it has appeared. I think with the gutters and heavy snow has caused it to come through.

What do you suggest I do on the outside (other than cut the render back). I had a builder look at it and he said that in his opinion it was best to just fill the cracks and then use some good quality paint on the outside as the cracks were not very large. Do you think this is good advice?

[wes56]

the only paint to use on render is masonry paint. its not for filling cracks of any size.
you could seal the cracks with some polyurethane sealant and wait and see.
is any render blown or loose?

the water penetrating the render will penetrate the solid wall and should show up inside on the other side of that wall.
your dpc is bridged by the render and render is in contact with the ground. you could have rising damp.
you could also have rotting joist tails where they sit in the wall.
do you have through ventilation from front to back of the house including underthe hallway?