Waterproofing bricks

Merlin5 · 14 May 2020 at 20:09

I've got some areas in my kitchen that I'm going to repair but not really sure of the procedure. But since its summer this is the best time while my walls are dry. I've got bubbling on the paint. I'll need to presumably smash away the plaster back to the bricks.

Then very importantly I'll need to waterproof the bricks so was wondering what brick sealer is recommended? Everbuild 402? Thompson's water seal? And will I need PVA on top of waterproofer? I believe PVA helps with plaster adhesion.

And then I guess it would make sense to brush the water seal
on the outside of the wall as well so there's a double protection from any water ingress?

It looks like there's a metal edge strip, I guess I'll need to get a new one of those? But it's going to need replastering which I've never done. Will I need to learn how to skim?

Dis86 · 14 May 2020 at 21:10

Why's water penetrating through your bricks?

Merlin5 · 14 May 2020 at 21:17

Dis86 said:
Why's water penetrating through your bricks?

It happened gradually over a few years and I found out recently there were some leaking waste pipes where water was hitting the brickwork. I think that's the cause of the problem, and the leaks have been fixed.

Dis86 · 14 May 2020 at 21:20

Merlin5 said:
It happened gradually over a few years and I found out recently there were some leaking waste pipes where water was hitting the brickwork. I think that's the cause of the problem, and the leaks have been fixed.

Is your place just single skinned? It's highly unusual with a working roof, guttering and plumbing system that you should be getting any real penetration.
Although it can happen in older places if the bricks are starting to spall etc.

Merlin5 · 14 May 2020 at 21:24

Dis86 said:
Is your place just single skinned? It's highly unusual with a working roof, glittering and plumbing system that you should be getting any real penetration.
Although it can happen in older places if the bricks are starting to spell etc.

No idea. It's an old Edwardian house. I had a damp proof course put in when I bought it in 1987. Whether it's to do with damp proofing from the ground up or penetration through the bricks I don't know but I think it's more likely water retention in the bricks. Anyway, apparently damp proof courses are a waste of time.

Dis86 · 14 May 2020 at 21:27

Id check the above first. It could be penetration but the cause is more likely to be something else and probably an easy fix. Check your roof, gutters and any surface drains first.

eviled · 15 May 2020 at 07:22

If you have fixed the leaks then it should just need to be repainted after it’s dried out, probably while stain stop undercoat.
Could take a while to dry out

fastwunz · 15 May 2020 at 07:37

The most important thing is to diagnose the cause of the water ingress.

damp proof courses are not a waste of time. Not sure where you heard that one! Provided they are installed properly and in appropriate circumstances that is.

fastwunz · 15 May 2020 at 07:39

That is a very common place to see damp. Usually it’s due to penetrating water owing to raised ground levels externally causing a bridge above any damp proof courses or drainage.

SeatIbiza · 15 May 2020 at 10:06

fastwunz said:
The most important thing is to diagnose the cause of the water ingress.

damp proof courses are not a waste of time. Not sure where you heard that one! Provided they are installed properly and in appropriate circumstances that is.

What sort of DPC was installed? If it was a chemical one then, yes, it is a waste of time. I find it unlikely, but if it was a proper DPC, then not a waste of time.

Pictures of outside please.

fastwunz · 15 May 2020 at 10:34

SeatIbiza said:
What sort of DPC was installed? If it was a chemical one then, yes, it is a waste of time. I find it unlikely, but if it was a proper DPC, then not a waste of time.

Pictures of outside please.

sorry yes I should have been more specific. Chemical damp proofing can do one - stupid practice.

proper damp proofing with membranes etc are effective.

Merlin5 · 15 May 2020 at 15:27

Thanks guys, I'll take some external photos later. Yes, wouldn't it be likely to have been a chemical DPC in 1987? I'm sure I've got the original details from the company that did it, I'll try and find it.
fastwunz, there's some stuff on the net about DPCs being snake oil,

https://www.heritage-house.org/damp-and-condensation/the-fraud-of-rising-damp.html
https://www.architectsjournal.co.uk...a-myth-says-former-rics-chief/5204095.article

but I think they're referring to chemical injection. I'll take your word that a membrane DPC would be effective and it might well be that the cause of my damp walls is due to an ineffective DPC, which tbh, is way past its original 25 year guarantee. Trouble is, I've no doubt it'll be very expensive if I do have to get one installed.

eviled said:
If you have fixed the leaks then it should just need to be repainted after it’s dried out, probably while stain stop undercoat.
Could take a while to dry out

Yes, having taken another look, I might be able to just scrape away the top surface of paint and repaint. But I think the edge mesh strips have rusted, won't I need to chip plaster away and replace those? Can you link me to a stain stop undercoat and does it provide some sort of moisture barrier?

eviled · 15 May 2020 at 17:46

If you’ve truly solved the water ingress then sand it all bare and leave for a few months to dry completely.

You don’t want to create a moisture barrier really but previous damp stains tend to show through new paint.

I’ve just used ronseal damp seal, as it’s what was in th in-laws shed, and its done the trick on old leaky ceiling stains

-> do make sure the water ingress is fixed first though

Merlin5 · 15 May 2020 at 19:40

I don't truly know though if I've solved the water ingress. Who would be the best person to tell me? I could get a company that does membrane DPC to come here and inspect but how much could I trust they're not just selling their product whether I need it not. Or am I better off paying an unbiased qualified expert to diagnose the water ingress?

Here's some pics. You can see the holes where the DPC was drilled outside the kitchen door which is where the internal plaster has slightly blown.

You can see some some staining on the bricks where water was hitting it from above.

In these two pics, there was leaking from the plastic pipes above my flat which have been fixed now. Whether they were the sole cause or cause at all of the internal wall damage I don't know.

[/url

Merlin5 · 16 May 2020 at 09:58

fastwunz said:
That is a very common place to see damp. Usually it’s due to penetrating water owing to raised ground levels externally causing a bridge above any damp proof courses or drainage.

Just taking you up on this point, when you say penetrating water, do you mean coming up from the ground as in rising damp and therefore needing a DPC, or do you mean penetrating through the wall horizontally from water hitting it?

SeatIbiza · 16 May 2020 at 12:37

LOL, not one, not two, but THREE chemical DPC lines. WTF.com Cowboys.

Flemish bond = solid wall. One thing your pictures don't show is airbricks. Have you got any? If not, expect rot to your joists...

Likely you were getting water coming in due to that concrete floor allowing water to go above the original DPC. I suspect there is one underneath that concrete render band and, obviously, that band will bridge over the DPC. As above, I'd let it all dry out fully over the summer and decide from there. Whatever you do, don't let the damp proofing idiots at your house again. To retrofit a physical DPC would be all but impossible and the chemical is a con and doesn't resolve the issue.

The other option is you could try stormdry. It's fantastically expensive @ £120 for 5 litres, but it is good. It's basically goretex for your brickwork...

Merlin5 · 16 May 2020 at 12:48

So what are you saying? That no DPC, even a membrane one is not possible or worthwhile?
Yes, the kitchen floor is concrete. How does the concrete floor allow water to go above the DPC?

SeatIbiza · 16 May 2020 at 13:16

Chemical DPCs are a con and don't work. You have all the evidence there, three have been installed by the looks of it in your wall. A physical DPC would mean cutting it into the bricks and is all but impossible.

Your house is likely Victorian aged, it's not been damp for it's entire existence, so something has changed. You've fixed the leaks, so I would just let it dry out and take from there. It will take an AGE to dry properly. Alternative is the waterproofing I mentioned.

I was meaning the concrete outside, not inside. That ground level is likely higher than it was originally...

Merlin5 · 16 May 2020 at 14:08

I see. I didn't know how a membrane dpc is installed but as it means cutting into bricks and you say it's all but impossible, then that clearly means I can forget about a damp proof course completely.

Ok, so the waterproofing alternative you mentioned. I've had a look at the Stormdry masonry cream you mentioned. Yes, £120 on Amazon. Looks really good, 25 year proven protection, you've piqued my interest in it!

Do I simply brush it on all the external brickwork and that will prevent further water penetration while the inside is allowed to dry? And because you said it takes an age for the inside to dry, how will I know when the inside is ready to redecorate? There's some plaster inside right at the bottom of the wall that is flexing and feels hollow when I tap it. Shall I just smash it out now?
The house is Edwardian era I believe. But do you think it's possible my issue could be rising damp, in which case anything other than a membrane would be ineffective,? Or more likely to be fixable by sealing porous bricks?

SeatIbiza · 17 May 2020 at 21:25

There is no such thing as rising damp. Your THREE chemically introduced "DPCs" should tell you that...google some sh!t and educate yourself. If it was rising damp how has it got through those dpcs? As terrible as they are, they will at least temporarily do something.

Victorian or edwardian, that property was designed to breathe and now is likely sealed up with double glazing, insulation etc. and hence the problems (aside the physical leaks)

As for the stormdry, yes it's painted on like normal and as it's like gore tex it doesn't matter if it's wet below as it's breathable. It's a good product and your pointing looks good. Give it a go. £120 vs a property value is nothing. Survey would be £350+vat minimum!!