Wall of woes....

[discobarry]

Hello everybody,

I know it has been a wee while but now we are wanting to get on with the next stage of our house. To give you a little background information we live in a 18th home with some 19th century additions lower down in the building, I am today asking for advise on the earlier part of the building.

In our home we have high humidity levels, we help this a lot by having windows open the majority of the time from spring onwards and as much as we possibly can in winter time. On the gable end of the home downstairs in the living room we suffer some damp issues, which we are pretty sure is condensing mould but we also suspect some of it is coming through the walls. If you look at the attached pictures, the first picture is our gable end and what we currently have is a dug out section to the left hand of the chimney stack with a retaining wall. On the right hand side of the gable end there is simply a french drain. Under the soil surrounding all of that is some crumbly old blue sheeting which i assume is to try and stop damp getting down there in the first place.

We were wanting to lime plaster our front room as this is breathable and better for the house but we didn't know and nobody else who comes round seems to know what we should do regarding the outside of the property to limit what moisture comes into the house. We understand moisture is always a feature of the old property but we also want to do whats best for the property, but we don't have much of a clue!

I'm looking forward to your replies, and i'll even tell the other half about your expertise

https://www.facebook.com/photo.php?...829485374.1073741826.746965373&type=1&theater

 

[discobarry]

Please tell me if you cannot view the picture as it won't let me upload it?

 

[JHD]

I can't view the pictures. Try using something like Picasa.

 

[discobarry]

 

[88v8]

Can't quite get the hang of this; is the gable end sunk into a bank? To what depth?
Nice stonework, btw.

Ivor

 

[discobarry]

Approx 3 feet, but only to the right hand side of the stack. The left hand side is dug out to the base of the building with a retaining wall.

 

[88v8]

And is the damp more prominent to the right or the left?

I'd be digging out the other side + creating a retaining wall, if that's possible.

We have damp/black mould at the base of the wall in our sitting room, which was until recently 2ft underground. The house as a whole is about 65% rh atm, and up to 80% in the cellar when the dehumidifier needs emptying, but nowhere do we have condensation mould even though the walls are solid and entirely uninsulated.

Logical to start by assuming it's the undergroundness that's causing the problem, and look beyond that only if proven otherwise.
The 'proof' may take some time, as I believe it takes about 1 month per inch of wall thickness to dry out a thoroughly damp wall.

Ivor

 

[discobarry]

Well i wonder why they didn't do the other side as well? the mould is more to the left hand side where it is dug out and with a retaining wall but apparently the mould is from condensation in the living room. We kind of find this hard to believe as in winter we use the stove all the time and the humidity stays at around the 50% marker and even lower when it's on all the time.

I can't see why we can't dig it out around the right hand side, i'm getting in touch with the builder who originally did the work to find out what else was going on at the time. From what we have been told the side where it isn't dug out properly is where there was a bad flood which came through the wall, which means it makes even less sense not to dig it out!?

Urgh, Old houses are a bind sometimes.

 

[88v8]

Urgh, Old houses are a bind sometimes.

Yes.
Right now the chap who built our drystone retaining wall last year, is out on the east terrace digging out the (clay) drains to find out why we have no manhoie, or whether we do. We, or rather, he, lifted up both the massive iron covers in the lane below the cottage to see whether we connect to one or both, and found the answer is neither. So where our drains go....
Now he's cutting another hole in our terrace to create a manhole for the kitchen drain, from which we can send a camera in to find where the drains go, hopefully.
And on.

A bind, indeed.

Ivor

 

[billybuntus]

On the subject of dehumidifiers in cellars. I too have one to keep mine at 50% RH and have fitted a condensate pump (dehumidifier waste pipe which not all dehumidifiers have is fed into the tank of the condensate pump and as soon as the tank is full the condensate pump starts up and pumps the water to an external drain.

Obviously you need electricity and a small bore plastic waste pipe fitting up to an external drain but mine works very well and I never need empty a water tank again.

I just used the pvc pipe that you use with fish tanks. Cheap and cheerful and I didn't need to cut a giant hole through the house wall.

 

[discobarry]

I don't have a cellar BillyBuntus.

 

[88v8]

Ahh, but I do. A wine cellar, moreover. OK, it's also a beer cellar, a pickled gherkins cellar and a cupboard full of shopping bags cellar, but we'll gloss over that.
I even have a condensate pump. What I don't have is a path from the dehumidifier to the drain, but thankyou for the thought.

Ivor

 

[discobarry]

Out of interest, after you dug out your 2ft, what did the humidity eventually drop to? As of this morning we are at 61% RH. Beautiful weather out though again, so i'll no doubt be doing even more strimming and mowing.

 

[88v8]

Out of interest, after you dug out your 2ft, what did the humidity eventually drop to? As of this morning we are at 61% RH.

It's not really possible to measure the effect here, as there are no internal doors in the house - not 'open plan', just no room for doors - so with the exception of the cellar the rh tends to be a blend of the whole house.
The stones at the foot of the sitting room wall that were growing mould are still black because I haven't yet been at them with the Jeyes Fluid, I'm waiting the 24 months I expect it to take for the wall to dry out. After that I'll clean the stone and we'll see whether it's worked, or rather to what degree.
This is one of the problems with anti-damp work, it takes so long for the efficacy or otherwise to be apparent.

Our rh peaks in early summer when the heating is off but the sun not yet warm, rises into the 70%s. Falls briefly to 45% in midwinter when we have both woodburners going every day and the house has dried out, then rises to 50% when we start lighting them more sporadically. Currently, around 65% in the three rooms I measure.

Normally one only gets condensation on a wall if there is a cold spot &/or the internal air is damp. Do you have a source of damp such as drying washing, or shower room with no extractor, or no extractor in the kitchen? Or is the stone thinner to the left and therefore colder?
Is it a north wall? I guess from the pic that was afternoon, so the wall has a SW aspect?

Ivor

 

[billybuntus]

Ahh, but I do. A wine cellar, moreover. OK, it's also a beer cellar, a pickled gherkins cellar and a cupboard full of shopping bags cellar, but we'll gloss over that.
I even have a condensate pump. What I don't have is a path from the dehumidifier to the drain, but thankyou for the thought.

Ivor

Same setup as me

I just ran the thin tubing discreetly then one small15mm hole through the wall beneath the ground floor and straight out to a drain.

I don't envy you emptying the tank. It's another 'task' I now no longer have to do.

 

[discobarry]

Our gable end wall faces north west, I would like to dig out to the bottom stones of the house. I just worry as the old owners obviously dug down as they have put in a 'french' drain but filled it all in again. TBH the damp isn't 'that' bad but the humidity is high and we want to re-plaster in lime so we want to be sure we won't undo our good work. Hmmmm.

 

[88v8]

As with many old house/damp topics, hmmm is about the size of it.
Sometime one just has to say, let's try this, it may do some good and will do no harm.

Usual caveats about undermining the foundations... if the house was built into the bank from new, it may not take kindly to having the support removed on that side.

When we dug down at the back of our house, it was apparent that the lower, buried, courses of stone had never been intended to see the light of day, but I decided/guessed that stability would not be affected and went ahead anyway. We lowered the level and put in what I believe is a well constructed french drain. Perhaps in a hundred years I shall be proved wrong and the wall will subside, oooer.
More likely, subsequent owners will have failed to maintain the drain, decided it would be a good place for a flowerbed and filled it in again, heyho.

Ivor

 

[Zebra]

Hmm indeed. Two years ago I went down the long and winding path to dry walls, and it was a slog, ending in rather drastic measures which one wouldn't undertake lightly and only if one had tried everything else. I agree, you have to try something, give it time to dry, see if it makes a difference, then try something else. Is the french drain working? Have you had a poke about to see whether it is dry a few inches down? Does the brickwork seem damp on the external face, down inside the gully behind the retaining wall?

 

[discobarry]

The french drain runs at what i would call the base of the building, so in reality it is roughly 3feet underground. No water ever comes out of it into the drain which runs at the side of the house....just bits of muck sometimes. So i think it isn't doing too much.

I have a heritage guy coming to do some re-pointing in lime soon (hopefully) so i'll probe him in the nicest way a Yorkshire lad can.

 

[Zebra]

And what is it backfilled with? Is there still soil up against the wall? Or is it gravel or similar? I'd have a little dig to see whether it's dry below the surface, against the wall of the house.