Waterproofing Brick wall

[Carolinexxx]

That's better. Thanks.
I need some advice on waterproofing my external brickwork and I also want to paint it. Do I put a breathable sealant on it then paint it or the other way round or just paint. CWI damage but I can't afford to get it removed. Hope someone can help.




Cumbria

 

[^woody^]

A waterproof coating and paint are probably not compatible

 

[JohnD]

Please explain how it is damp.

 

[Carolinexxx]

My internal walls are wet and I can only assume it is because of rainfall. There is an unused drain next to the wall outside but after having someone look at it there is a gap in the bottleneck which I will be getting capped but it didn't seem the cause as one wet wall is on the other side of the door away from it. I will put pictures on to show what I mean.

 

[JohnD]

show us what is above those patches. A leaking gutter or pipe?

Is it a solid (concrete) floor?

Does water lie on the doorstep or paving after rain?

Can you see a damp-course in the external wall? It would be about two bricks above where ground level used to be when the house was built. How old is it?

I can see damp on the corner by the hinge side of the door, just above the skirting. Where are other damp patches?

 

[Carolinexxx]

Gutters and pipes are fine. Floor is solid concrete with terracotta tiles under laminate. Water used to like on the doorstep but I got a new front door 2 weeks ago so is now sealed. There is dcm all round the house which I think was built in the 1930's it's an old council house. There are no damp patches just walls are damp to touch and wallpaper was coming away so took it off till problem is solved.

 

[JohnD]

Water used to like on the doorstep but I got a new front door 2 weeks ago so is now sealed.

If water was soaking into the walls two weeks ago, it will take months for the wall to dry.

Photos of the outside showing the wall, DPC, outside doorstep and bottom of door would help.

 

[Carolinexxx]

So you think the water from the floor has soaked into the CWI and I should wait a wee while to see if improved then?

 

[JohnD]

no, I think water has soaked into the bricks. IME CWI does not hold water.

 

[Carolinexxx]

My builder said that was the reason my walls were wet. He said the rain has penetrated the outer bricks, wet the CWI and is coming through to the internal wall. He has advised tanking but I thought if I just sealed the brickwork outside, I won't need to tank it. That's my reason for asking about waterproofing.

 

[JohnD]

If you can find and remove the source of water, the wall will dry out. Tanking or sealing will prevent it drying.

Rain is unlikely to make a wall wet unless it is exposed to frequent driving rain and/or has cracked, broken or missing bricks or mortar. I have a well-pointed wall exposed to coastal storms; with CWI. It is not damp.

 

[^woody^]

Probably time for a new builder.

It looks like there has been some work there previously with that new plaster and repointed bricks.

You certainly don't need internal tanking.

CWI can get wet, but it tends not to permit dampness to move horizontally to the internal wall. Not impossible, but not the most probable cause, possibly the last thing to suspect.

If you have damp at the bottom of the internal wall, then the cavity needs to be checked for blockage at DPC level.

Exterior brickwork should have sound pointing and no cracks - irrespective of any damp issues.

 

[Carolinexxx]

Thanks so much for your advice.
Well I think I have everything covered now.

• The source of the wet walls can either be the previous door leaking so need to wait longer for drying out.
• Brickwork may need pointing.
• The broken bottleneck on the drain could have caused it which is due to be capped

Definitely not CWI being wet or rain penetrating walls and doesn't need tanking.

 

[JohnD]

broken bottleneck on the drain

if you can show us this damaged drain, as well as the other things I mentioned, it may be informative.

 

[Carolinexxx]

The drain I showed earlier but the gap is just underneath the bottleneck on the drain, on the wall. I had the drain doctor come and cctv the drains. Everything was great apart from the gap.