I’ve got damp coming through plaster on bathroom wall,the house is old so no cavity and very open to elements.pointing looks good and roof also.I was thinking of using a sealant to water proof the brickwork and just wondering if anyone has any advice on wether they work,which brand worked for you.stormdry,is the market leader but cost four times as much as the others I’ve seen,if it works then sound I’ll get it but if cheaper quality options I’d prefer them.
Cheers

I used Synthapruf when I was building my brewery in a very damp washhouse (with earth banks round two sides). It was dripping wet – you could see droplets running down the walls!
Took a few coats but the insides are now very dry.

The paint is pretty messy stuff to work with, and you’ll never use those brushes or rollers again – but it did the job

Old houses are supposed to breathe, hermetically sealing the brickwork is about the worst thing you could do. Look at better ventilation for starters (particularly in a bathroom).

Find out where the water is coming from before you try and treat it.

You sure it’s coming through from the outside? In a bathroom this could just be large amounts of condensation, warm steam against a really cold wall. I’m not keen on the idea of sealing bricks, they’re pretty waterproof by design, you’re trying to treat a symptom rather than the cause. An acutual expert may be along to contradict me in a minute.

Storm dry is excellent stuff, have used it on a number of masonry and concrete buildings (for work) and had really positive results from them with regards to damp reduction.
Easy to apply and once it’s dried there’s barely any noticeable colour change to the original pre-application.

Facade cream, not cheap but it works.

I’ve used THIS in our dinning room. Re-decorated over the summer and injected in into the walls behind the (removed) skirting boards.

No sign of damp yet where i have injected it, even with the biblical weather recently! On current evidence i would say it works, I haven’t been able to address the cause yet so I am still getting damp where it isn’t injected.

Fixing the cause is a whole different issue, house is built into a bank and the water from above runs directly towards the house.

Member

Facade cream, not cheap but it works.

The sovereign version is very very good. Its silicone percentage is the highest on the market I believe. Used to very good effect on various areas such as a mates brand new build garage.

It’s the Sovereign one I used wrightyson, recommended on here some years ago, might have been by you!

might have been by you!

Quite possibly so as I’ve definitely recommended it on here before. Used for the right applications its brilliant.

Batton n slate the exterior walls. It’s a common look round these parts on end terrace houses.

Are you sure it’s permitating the brick though

Old houses are supposed to breathe, hermetically sealing the brickwork is about the worst thing you could do. Look at better ventilation for starters (particularly in a bathroom).

So much this.

If it’s bathroom it’s likely condensation. Ours does it something chronic (solid brick, lime mortar)
Open more windows, try and introduce some form of through flow. Draughts are good. Worst thing people do to old houses is seal them up.
Is it doing it in any other rooms?

Thanks for replying,very helpful too.The bathroom window is left wide open 24/7,I am fairly certain it is from the rain water passing through the exterior wall as all damp and mould is just on that one area,all other rooms are good,but as soon as it stops raining I do need to have another look.This one wall is directly above neighbors off shot kitchen and rain just batters the side of it.
Cheers again for advice👍

I used Thompson waterseal on the outside of my garage, can’t tell it there when it’s dry, the bricks stay pretty dry even in torrential rain.

Was about to say Stormdry – not something you’ll find in B&Q/Wickes.
Its an industrial grade sealant so you’ll need to find somewhere thats authorised to stock/sell it but there is little to better it.

Point of order,

pointing looks good and roof also.

Do they “look good” from a vantage point of standing in your back yard, or have you properly checked that they are?

You really need to ascertain conclusively why it’s damp. If you start randomly slapping sealant around outside you might find that you’re trapping moisture *in* rather than *out*. (Which could well be what modern plaster is doing.)

The room underneath it isn’t damp. Rather raises the question, “why not?” when it’s the same wall.

I just love these ‘damp’ threads, threads on religion are so passé 😁

Ventilation. Even though your window is open 24/7, the ‘damp’ maybe forming at that spot due to it being a particularly cold spot? Has the exterior pointing at that point been done with a Portland base? Ie cement rather than lime?

Investigate all possible causes thoroughly before administering the sticking plaster of silicon based sealant.

This ^^

I see the pros are in 😉

Have you got a radiator and an extract fan (which gets used) in the bathroom?

wrightyson

Member
I see the pros are in 😉

😂 damn straight, cheers chap! 🤣

I see the pros are in 😉

I see you’re being totally helpful to the OP in fielding their question.

Post 9 sweet cheeks.

Gonna keep an eye on this thread, similar issues myself. Do dehumidifiers do anything for this problem?

Old houses are supposed to breathe, hermetically sealing the brickwork is about the worst thing you could do.

My old house is rendered and painted, so it depends. Anyway, a coat of Thompson’s worked a treat when I had some water penetrating through.

Solid brick wall with have terrible thermal performance, especially if it’s full of water already. Couple that with a warm humid bathroom environment, topped up on a daily basis. My money is on cold wall condensation. Especially if the room below is dry.

A window for 24/7 ventilation is never going to be enough. Still, slapping something on the outside will at least allow you to eliminate penetrating water from the possibles.

Driving rain can go right through brick so it’s very possible this problem is that and not a ventilation issue. I know because it does it on my house and occured where walls had been replasterd which replaced the original internal rendering. Years ago the internal faces of external walls were rendered before a top coat of plaster went on and that render holds back moisture pretty effectively. Strip that back and put plaster straight to the wall and it’ll suck any penetrating damp out of the walls. My walls were treated with 2 coats of Thompson’s which did little more than bugger all. I then used the Sovereign Facade Cream after a dry summer week and 5 years on there has been no recurrence of the problem.

Just to note the wall had also been repointed so that wasn’t the issue.

Have cold showers for a few weeks and see if the damp dissipates.

Also make sure to check for leaky/blocked gutters.