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I'm having trouble with damp in the kitchen. I initially thought it was a case of kitchen ventilation so installed 2 extractor fans (one cooker hood, one general). I then thought it could be rising damp so I installed a chemical injection damp proof course as the house is 118 years old so there isn't any sort of damp course.

I then noticed that a flat roof covering a small part of the kitchen was leaking so relpaced it with a fiberglass roof and increased the insulation at the same time.

Still the damp continues. My next suspect is penetrating damp due to my adjoining neighbour's poor quality guttering or maybe due to driving rain as the wall is exposed to the prevailing wind.

I'm considering applying a masonry waterproofer like Thompson's waterseal  https://www.screwfix.com/p/thompsons-water-seal-clear-5ltr/52043

Has anyone any experience or advice on using this stuff?

Thanks,

G

I’d probably get a ladder and clear out the gutters first, see if that solves it. 

Checking for obvious water leakages from guttering and outside sources is the first step. Watching videos from https://www.youtube.com/user/stibnite11/featured is very enlightening.

The gutters on my side are fine and the neighbours gutters are clear but they are badly installed with excessive pitch in places resulting in run off and uneven pitch in other places resulting in pooling and potentially overflowing.

This would be something I'd sort if it was my stuff, but the neighbours rent the house and the landlord is useless at getting any repairs done.

I used Thompson's waterseal on parts of my house about 18 years ago. It was really easy to use, just applied it with a coarse garden sprayer. Although from memory you do need rather a lot of it if you've got a large area to do. It could be worth while as it's still a relatively cheap fix if penetrating damp is the problem. 

Are you sure it's water coming in though and not just condensation? Is it the whole room, one wall or just odd patches that are affected? Even with the increased ventilation you've installed you can still get cold spots where air doesn't circulate properly, leading to damp.

I'd suggest being very certain of the cause  before spending more money (given your track record 🙂). Also, I'd be cautious of "waterproofing" a wall so old. 

There's obviously potential pitfalls, but assuming you could do the guttering 'on the quiet', even potentially without the neighbour's quite registering what you're up to, are you skilled enough to sort the neighbour's guttering out yourself?

Sometimes something is only a bad idea if it goes badly, when it does seem like one in abstract....

Edit: Possibly you could gradually sort it a section at a time while 'doing things on your roof'. I see clearly why it could be a poor suggestion BTW.

Most 'historic houses' benefit from maintenance first. Check all that's good. Correct the gutter drainage and maintain. Don't rush into waterproofing/cement renders/waterproof paints. The wall can absorb huge amounts of water and then you lock it in. It can take a very long time for a wall to dry out if its lime mortar and stone constructed. Check where the damp is - abutting concrete, lack of external run off drainage, broken drains, surface run, pointing and breathability- all to consider. Old houses had fires. New houses block all draughts. Check the relative humidity of your rooms for condensational moisture; small rooms and high humidity with an external wall may accumulate condensation on gypsum. It may be an insulation issue and a breathable insulation. Outside ground levels higher than rooms?

Just some ideas

It would be nice to know the exact problem. To be fair, the extractor fans and the flat roof were certainly problems that needed doing, and I did them myself so cost a lot less than getting someone in. Not sure about the chemical DPC, it's debatable it they actually no anything or if rising damp even exists. It wasn't too expensive as I did all the drilling etc myself.

You say 'trouble with damp' but could you be more specific?

I've renovated  several houses with damp issues but without more information I couldn't easily suggest anything.

What does it look like, where is it both in terms of in the room (bottom/top/all of wall or ceiling) and where that room sits re internal/external walls and aspect. Is it permanent or intermittent etc?

One thought however, if you've injected a damp proof course did you remove all the affected plaster (and beyond) and replace it with a non gypsum based plaster and does it definitely not breach the damp proof course? If you didn't the damp may never go away.

Also, given its age there almost certainly isn't a cavity but is it a double skin of bricks? I know that's nearly always the case but I once had terrible damp issues in a kitchen which had a single skin external wall.

I'd avoid the Thompsons Water Seal, its only a temporary fix and can cause more problems than solves in some cases.

Our builder used Belzona on a single skin brick wall (garage conversion) and it has worked an absolute treat. No issues at all.

http://www.belzona.co.uk/en/products/5000/5122.aspx

Got any photos? Have you ruled out condensation?

Sounds like condensation on a cold wall - especially common in kitchens with single skin brick walls.

If a wall is soaking wet, a rule of thumb is 1 inch per month to dry... But I would do everything I could to stop additional water getting in i.e. faulty gutters, leaks etc

Can you paint the wall with silicate paint or similar to give it breathable protection?

The problem as I put it is moisture coming through the plaster (gypsum based) and salting out on the walls up to about 5 foot off the floor. This has resulted in paint coming off the wall, back boxes and connections on electrical fittings corroding, cupboards getting mouldy and woodwork (solid oak cupboard doors) warping.

The room is a rearward extension of a terrace, with the wall that causes the main problems indeed being of non cavity double brick construction with a stone chipped cement render on the outside and a cement render gypsum finished wall on the inside.

When I did the DPC I chipped off about a foot of the cement back to brick. I never replaced the render as it's behind cupboards, although I did add ventilation to the area to try to move air around behind the cupboards and reduce damp.

I had thought this but, in some places, where there is a wipeable kitchen specific paint, around the cooker hob, the moisture bubbled the paint without breaking the skin. suggesting that it was coming out of the wall.

Is the outside render/stone chip sound with no cracks or blown patches? If it's not it's possible rain water could be getting funneled in between the render and the brickwork with no escape route. 

As far as I can see the render is good, which made me wonder as I thought that would be adequate to keep the weather out.

Have a look at this.

https://www.heritage-house.org/damp-and-condensation/types-of-damp-what-hav...

When I did the DPC I chipped off about a foot of the cement back to brick.

Was the brick wet? on the outside or inside. If not, it may suggest your render is sound and its a condensation/cold wall issue which may mean insulation, ventilation and maintaining lower humidity (cooker hood).

If wet, water can get in. Also blown water off the underside of a cill or back wall etc or undersized gutters. 

Rising damp affects the base of the wall but 5 feet up is a bit high. Condensation would likely happen at any height as could penetrating damp, depending on the source.

After DPC injection you should remove all affected plaster and about 1 foot beyond and replace with a non gypsum backing plaster. This could be plastering sand/cement or an actual cement plaster like Thistle Dri Coat

https://www.british-gypsum.com/products/thistle-dricoat?tab0=0

Its ok to skim over either of these with a gypsum skim which sounds like what you describe. If so, and the DPC hasn't been bridged by external ground level being too high (min  6" below DPC) or internally by plastering below it, then its unlikely to be rising damp. I've seen a few DPC failures because people have replastered with normal gypsum backing plaster and one where they had plastered down to the solid floor below the DPC.

The height of the damp, up to 5 feet, also points to something else. As others have said above, the external render/pebbledash on a house of that age is the thing I'd suspect. Older houses should be able to breathe, 'modern' cement (Portland) as opposed to older lime cement doesn't breathe well at all and can trap moisture behind it. Cracks in it may be tiny and hard to see if at all.

I'd consider removing the external render next unless there's something very easy/cheap you can do first just to be sure.

As a temporary measure against damage to the wooden cupboards you could use a dehumidifier until you solve the problem.

If the wall was wet and not fully dried out then painting a plastic paint over it will certainly bubble up as the water previously trapped inside tries to get out. Wipeable and bubbles seem to imply am impervious paint which I wouldn't apply on an old house at all If I could avoid it, and certainly not one with a damp problem.

Any moisture that gets in, or is trapped in from before and not yet dried (1 month per inch of wall thickness) needs to come out somewhere. If it stays inside the wall eventually it will freeze, expand and crack or blow the render off, letting more water in.

I would remove the old paint mechanically then use a fully breathing paint like clay paint inside (or limewash if you are time rich money poor, or keim paint if you are money rich), then wait 9 to 18 months after checking and fixing the outside wall.

No quick fixes I am afraid

The quick and effective fix would be to get a dry-lining specialist in to line the wall then dry-line it with KIngspan or Cellotex insulation and insulated plasterboard. The room will be dramatically warmer, quieter and more pleasant. Remove the render from the outsiude to allow the wall to dry out and check that it;s not getting soaked by rain. 

As somebody else mentions above, old houses had a fireplace in every room so were well ventilated, especially as coal was as cheap as chips. 

Thanks for the link, some very good info in there even if you're house is modern clay brick it's worth noting.

Especially like the take on "rising damp"

I'm sure removing all the render off a 25 square meter wall and dry lining the kitchen with insulated boarding would probably sort the problem. I'm not so sure this would be a quick solution or in any way cheap. Especially as I'd have to rip out the fitted kitchen at the same time.

Take off the external render and fit external insulation. That's almost certainly the best thing you can do in the long term.

I got excited as I have a problem wall by the kitchen... but it's over £100 a litre???!!! 

Where did you find that price? I was struggling to find one. It does say in the application notes that the concentrate should be diluted 1:7-9 depending on application. Could the price you found be for the concentrated stuff?

I e-mailed the company to ask where I could buy it.  They said direct from them ("0 next day or £12.50 for 3-day delivery) plus:

3litres £368.46

1litre £127.13

Which took my breath away rather, even if it is concentrate.  I only have a little wall that needs doing!

Well yes it wasn't cheap for a liquid but it was a lot cheaper than all the other damp proofing options and a small price to pay for a dry room.

It cost us £160 (inc VAT) and 1 litre did all four walls of a 6m x 3m garage.

Interesting thread.
We've got a North facing, large area wall, which gets next to no sun and can be damp as a result.
Looking at this: https://www.petercox.com/our-services/penetrating-damp/treatment/waterproof...

I'm wondering if it's worth splashing out on waterproofing it to improve its thermal efficiency (or more like total lack of it!).

only if the source of your damp is water on the outside gettign into the wall.

warm air (air inside the house) will dump condensation onto a cold surface; there's no substitute for inernal insulation and moisture barrier (dry-lining).

Interesting thread- worth a look;

https://www.spab.org.uk/sites/default/files/Control_of_Dampness_0.pdf