lime plaster - anyone recommend one in London?

[ftb]

Hi Does anyone know a good lime plasterer ? i Have a 1905 terrace with some damp walls. Would be grateful if anyone can share if this kind of plaster has helped them ? Also the costs involved ?

Found a dpc under the wallpaper but obviously it has not worked.....
I am reading that the house needs to breathe....
Thanks in advance.

We have a 1900 house and the basement suffered damp conditions. We did a combination of DPC injection at intervals pumped into drill holes all round the perimeter wall plus a DP membrane painted onto the concrete base and up the first foot or so of the walls to overlap the DPC level. It's been very effective apart from one corner where the house suffers seasonal movement and, I guess, sufficient cracks develop to bridge the DPC and capillary action draws water above it.

We didn't do anything with lime plastering at all.

nope

I did have one do some restoration work in a house of similar age, he was a bit of a specialist and was brought in by the main contractor.

However if you have damp in a house of thart age, a prelininary checklist (you may have already looked at these)
Is it external walls only?
How high up the walls?
Is there a tidemark?
Is it the same height all round?
Whch rooms?
Does anyone drape wet washing around the house?
how many airbricks do you have ventilating the subfloor voids? are they choked with cobwebs and dirt? If someone holds a cigarette by one, do you see the draught blowing the smoke in (or out)?
Has anyone poured concrete floors since the house was built? Or built an extension that blocks the airbricks?
Is there any sign that the ground level beside the house is higher than when built, e.g. with flowerbeds, paths and patios against the walls?
Does any external path or concrete slope so as to lead water away from the house?
When you look at the outside on a rainy day, is there drips or splahes from gutters or downpipes?

Chemical injected dampproofing is almost entirely useless. Can you see any evidence of black slate in the mortar joint 9 inches above where the ground level used to be when the house was built?

Have you got a water meter?

Is there anything near the damp patches that contains water? such as a radiator, a sink, a washing machine, or a watermain?

Thank you for this really helpful.

There was an extension and ventilation is v limited. I'll have a go through the check list and look under the floor boards if i dare.

Pulling up the carpet at some point to do wood floors and i think we will knock off the plaster. it is in the front of the house and one internal wall .

Full of angst about it but hopeful can resolve it with investigation, ventilation and maybe lime plaster.

House looks a bit like a squat at the moment as we are not in yet so need to get it sorted soon as i can.

lime plaster will be the solution as it enables the damp to evaporate continuously. so called damp proofing is effective for a few years but the damp in the wall builds up and eventually breaks through in a far more damaging way. The local conservation officer should be able to point you in the rigt direction for a tradesmen that knows what he is doing.

The true cure will be to find the source of the excess moisture, and correct it. Improved ventilation will also help if it enables the rate of drying-out to match or exceed the rate at which water comes in to the fabric.

I am all in favour of using traditional materials to restore the house to originality, remembering that when built it doubtless had draughty doors and windows, and open fires sucking moist air out of the house and up the chimneys. So lime plaster alone is not enough to cure the damp.

PigletJohn

You're obviously very well informed on this stuff. Sorry to hijack, but why is injected DPC useless? My semi submerged, basement is almost entirely dry now after the DPC was done.

injected chemical is usually sold to "cure" rising damp. Very often the old wet plaster is hacked off and the wall is exposed so it can dry. Allowing ventilation will usually dry a wall unless there is a source such as a water leak which replenishes the water.

"rising damp" is extremely difficult to cause under test conditions in brickwork for more than a few inches, even in a wall which is standing in a pool of water or a river. Old plaster can carry damp. hacking it off will stop it carrying the damp.

Very often people selling chemical injections sell it to peiople who have a leaking pipe, overflowing gutter, wet washing causing condensation, or some other source of moisture, and it will not correct these faults. If you do correct them, and ventilate, the wall will stop being damp.

Thanks Pigletjohn for the advice. it is appreciated.

checked a few things today - rear of house has been extended and the ground level is higher at the back than front. Also some of the back vents were filled with concrete when a path was laid. Noticed also a slight slope so water running from garden towards the house rather than away from it.

I will get someone in to look at this as probably will have to lower ground level at the rear and pull up floorboards to see if subfloor voids are doing anything.

There is a water main running across the garden. I suppose i can query with the water company that they are checked/maintained for leaks.suspect not.

Going to put in some more air bricks and get pointing re-done. There is also a thick cement render at the bottom of all external walls which does not help. Plus skirting boards are probably trapping moisture too.

"ground level is higher at the back than front. Also some of the back vents were filled with concrete when a path was laid. Noticed also a slight slope so water running from garden towards the house rather than away from it."

Grrrr
Typical stupid building work causing damp. Squirting in chemicals will not cure any of those defects.

An experienced local builder should be able to identify and correct such errors.

Consider having a trench dug round the house, with french drain, and backfilled with pebbles but no higher than original ground level. Better would be to simply dig the lot out and re-level, sloping away from the house.

If you're having new airbricks put in, one per two metres is now normal. One every metre would be better as you already know you have a damp problem. You will need to take up floorboards to inspect for rotten joists and clear out rubbish from the void.

If the walls are not all equally damp, and there are some patches that are particularly wet, search around there for pipes, drains and gutters contributing to the wet.

Thank you Pigletjohn
This is so helpful, i am really grateful for the advice

You need plaster master, 50years expereinced throughout London and Essex, [email protected]

You need plaster master, 50years expereinced throughout London and Essex, [email protected]

Hi ftb, did you manage to get a lime plasterer?

I need one as we have an old house with some damp issues.

Thanks in advance