Fixing damp issues properly

[freeedum]

Hi all, would love advice on how damp in property is fixed properly (not short-term fixes but we are looking for 100% resolutions/solutions).

This is for issues like rising damp and damp in chimney stacks. Costs? Time to fix?

(I am just trying to work out costs for my sister and what to expect).

Thank you for your help and for sharing your experiences.

thanks for responding! Is this for the whole house, few rooms, or just the chimney stacks? Has it worked and no damp problems since? May I ask what the cause of your damp was?

so sorry for so many questions.

£8k is do-able for us, we are just nervous about reno costs going up and have no idea what to expect.

Rising damp: check drains, soakaways and then look at where the dpc is and if the land/ path around is too high

Chimney stack - repoint and check flashings

Chimney stacks often have vents blocked as well, check if its capped and what vents it has.

Most damp has a source, ie guttering or failed flashing, or unfailed flashing has moss buildup, concrete on capped chimney pot cracked, brickwork on pointing failed.
Earth levels may have built up around the airbricks at ground level. Gypsum plaster which draws the damp on a masonry wall which has been improperly sealed off /insulated with drylining.

So many reasons.

But ventilation, heating, removal of improper materials which impede ventilation,( ie some modern concrete pebble dashing or plastic based paints breathing of the house), and above all actual leaks in pipework or collapsed drains /soakaways leaching in to masonry), faulty guttering ....that's where you should start.

Not with "damp proofing"

thank you @Ilovemyshed and @Nettleskeins

what tradesperson do I hire to do this checking of all these things i.e. finding the cause?

How old is your house and what sort of construction?

We've a damp patch on ceiling where chimney stack is. The flashing has to breathe at the vulnerable point; water is inevitably splashed up sometimes or is driven in by force of wind, usually it can dry out again but the build up of moss and cracked brickwork pointing is the reason it's got really bad. It's the source not the render on the inside but I do think if it had been lime plaster inside not gypsum with a "damp seal paint" the chimney breast would have just regulated occasional moisture from brickwork a bit better.

Whatever you do to block damp on inside just makes it go sideways and pop up somewhere else..imho.

@DrSpartacular it's a 1920s house. It has a tudor style appearance (dark brown wood on the outside). I believe it has solid wall brick throughout (no cavity).

I paid for an independent damp survey which was comprehensive and a few hundred pounds about 5 years ago. He said my damp mainly condensation and once I had new windows, roof felting etc it would improve, which it has. He said rising damp is rarer. Saved me wasting money

this might be useful Managing damp problems in old buildings (heritage-house.org) sorry if not

Roofer would check chimney stack. A trustworthy roofer. Maybe it's a missing slate for example.
A building surveyor could look at reason for damp at ground level, drains, concrete where it shouldn't be.

Good point about vent in chimney stack. There isn't one ATM in my damp chimney stack. Until chimney was capped v recently I didn't need one but now I do, despite the ventilation in the cap itself and i need to get one fitted! It's just a grille/airbrick but important with changes to way chimney is used (not used now)

Also get your chimney swept as soot deposits can draw water into brick, I think.

Ok, so as it's solid walled, you need to be really careful to get trades in who understand old houses and who won't sell you snake oil 'treatments' or recommend inappropriate 'fixes'.

The FB group 'Your old house UK - repair and conservation' would be very worth joining.

Old houses were built to breathe. Modern damp treatment is unlikely to work unless you've found and dealt with the source. Either water coming in or not enough moisture getting out - condensation from people breathing, laundry cooking etc.

I'm on renovation number 3, all of which have had damp in various places in the ground floor walls. After much trial and error, my approach now is.....

1. Lower the soil level against the wall.
2. Check gutters and drains are sound, and remove blockages so water can drain quickly
3. Check any lead flashing around porch roof, chimney stacks etc
4. Check all airbricks are clear.
5. Check and repair seals around windows and doors.
6. Check that the pointing in the foundations and lower wall is still solid. If it's gone soft and crumbly, I scrape out all the soft stuff, then repoint with a sand cement mortar mixed with a large dollop of external PVA glue.
7. As a last resort, I would remove every fourth brick in the bottom course and push a bendy wire bristle brush through from side to side to remove any accumulated rubbish in the cavity. I've not had to resort to this yet.

It's actually very difficult to find tradesmen who haven't been brought up on the dry lining /gypsum plaster/ sealing, school of damp proofing.
The wrong Roof insulation can also cause terrible issues with condensation and rotting timbers.
Smart Fitted cupboards on external walls with no vents gaps at all can also exacerbate damp, remember the old louvred doors were there for a reason!

Check that the pointing in the foundations and lower wall is still solid. If it's gone soft and crumbly, I scrape out all the soft stuff, then repoint with a sand cement mortar mixed with a large dollop of external PVA glue.

Absolutely do NOT do this.

If anyone talks about PVA, cement, gypsum, sealing anything at all, run a mile. This is not appropriate for a solid walled house and will cause damage.

A general builder not a damp cowboy specialist

Also check for leaks on the incoming water supply pipe.