House is quite old in parts – circa 1750, walls are rubble filled stone, quite thick, over 12 inches in places

Damp expert has recommended an electro-osmotic damp proof course

My surveyor has suggested these are not all that reliable on old houses and suggests a series of land drains instead to improve the drainage in the land surrounding the house

Anyone any experience of this?

I’d be going for the land drain option myself as well as plenty of ventilation. Older houses are often stuffy and damp because owners have blocked chimneys and fitted plastic windows.

With improved ventilation you also need improved insulation so as to retain as much heat as possible stored in the contents and structure of the building.

I considered electro-osmotic for my 30s house but realised that it probably wouldn’t work as it stops working when grounded (electrically grounded that is). I worked on drainage as you surveyor suggests and drilled out the mortar in 20cm sections in three passes just below floor level replacing with a more waterproof mortar. The wall survived without cracking.

I had numerous damp ‘experts’ (read: salesmen) try to tell me that my 1890 terrace had rising damp, and that this implied armageddon.

They all wanted to do ~£10k worth of removing render and plaster, injecting liquid DPC and replastering with their own special magic plaster.

I sorted the actual problem, which that the external render was in contact with the soil, put a bell cast bead on the bottom of the render, and a French drain to take the water away. Inside I improved ventilation. Sorted.

I’d recommend you get water away from the base of your walls (so the land drains seem like a good plan) and improve ventilation so that any moisture within the wall can escape harmlessly.

Your house has stood fine since 1750 without any need of electric probes in the wall. I suspect it will be fine without them for many years to come.

Dave

Thanks all

I’m going to get someone else to look at it

I think your surveyor knows best!

Really old buildings weren’t built with damp proof courses. It’s modern intervention and lack of proper care that is often the cause of damp; built up soil levels outside, poorly maintained rain water goods, cement pointing/rendering and the use of other non-breathable impervious materials – concrete floors, and plastic windows and blocked chimneys as already mentioned to name a few.

My place is 400-500 years old in parts, with Victorian and modern extensions. The newer builds have some damp, whereas the original part is very dry.

I wouldn’t have damp proofing injected into my place, it’s just masking the problem.

There’s an article on alicethearchitect.blogspot about just this, late last year, look for ‘rising damp’. Prolly 4 or 5 postings down. Preferably read it before spending money or signing anything.

And your floor coverings may not be helping.

Yes, agree with everything written so far.
The damp proofing industry is worth millions and although treatment often cures the symptoms it never cures the cause.

Google ‘damp proofing’ and it will be all people trying to sell you something.
A qualified architect knows damp rarely rises its causes are well documented. No 1 on the list is outside ground too high. Then poorly maintained rainwater pipes etc etc.

Also, check you don’t have a mains water leak. I believe the water board will do a check free of charge these days. Be prepared though if they do find a leak and its on your side they will serve you a notice giving you 7 days to repair it.
I had damp in my hallway, had it treated 2K+ it returned within three months. Checked the water main and although I couldnt see any sign of a leak ( it was lead) I replaced it with a new PVC pipe. Damp went within a week and never returned.

Likewise – my house had ‘rising damp’ – turned out to be a leaking shower tray – 99% of diagnosis are just rubbish.

Thanks again

Well 3 different surveyors have all confirmed there is damp – what they disagree on is the best way to cure it

hmmm…
As said above I’d look for leaking pipes, broken RWPs or gutters, how the external finishes butt up against the walls and fall away from the building and whether there’s adequate drainage.

aP – I’m a big fan of Jeff’s site – esp his stuff on Damp!

Thanks for that haven’t heard of Jeff before

How does one ascertain whether the ‘outside ground is too high’ or not?

If it’s within 150 of the internal finished floor level is a good starting point.

Sorry, 150 what, mm? So if the outside is 150mm higher than the floorboards inside, you mean?

it will be damp mate solid walls made out of farmers let over shite lol
not a cheap job i do damp proofing but in most case you just need a thermal break its when its warm in doors and the hot air meets the stone cold walls thats what draggs the damp through the walls
DO NOT DO injecting liquid DPC its crap dosent work they inject the bricks thats all ask the what about the pointing injecting is old school ive just done a celler converstion no silly pumps no damp pure dry walls 10ft under ground

Well I’ve had a £5K quote to fit DPC and re-plaster (3 bed terraced house)

Whilst that Telegraph article is interesting, to say there’s no such thing as rising damp in most cases is going too far. If you’ve got mould on the wall paper then it might well just be condensation but if you’ve got salpêtre/salpeter growing and turning the mortar to friable white sandy stuff then it’s real rising damp. You may also find salt deposits as the rising water dries out leaving salt deposits behind.

There’s a book – ‘Old House Handbook’, Hunt, R and Suhr, M, which has a chapter or so on just this. It includes a pic of a house with a chemical dpc injected into blue engineering brick lower courses. That tells you all you need to know really.

And this too, of course…

http://alicethearchitect.blogspot.com/2010/11/myths-and-legends-of-buildings-part-1.html

If there ground is very damp, you need to improve drainage rather than just worrying about sealing the house, which is very expensive, and often just moves the problem further up the walls – or somewhere else. If there is lot’s of water present it won’t just vanish because you’ve put a DPC in, you’ll still have a damp house, just be several £k poorer…