Damp on external wall

[rsi]

We moved into this house about a year ago, its an old detached house over 100 years old.

the pointing needs redoing but i've been waiting and saving a bit of money first.

I've noticed this damp outside the kitchen (same wall as the boiler is housed, which is in the chimney breast) a while back.

But, we've had lots of rain, and the damp seems much worse than it used to be, can anyone advise on whats happening please?

tia!

Untitled

• rsi
• 20 Dec 2012
• 1

Untitled

• rsi
• 20 Dec 2012
• 1

Untitled

• rsi
• 20 Dec 2012
• 1

 

[joe-90]

I'd be looking at that drain if I were you. Now - not when you can afford it.

 

[TheVictorian]

I agree, I'd be digging up the tarmac/concrete to see what is going on under there.

Suspect that there is a leak from the drain causing ground to saturate, the brickwork is sitting on that and I suspect the moisture is rising up.

The biggest concern would be future issues as most houses of this period have shallow foundations you could be causing all sorts of structural issues in the future...

 

[rsi]

wow really? I had never even though of that. Who would you recommend I get in? a structural engineer or a builder?

Thanks!

 

[^woody^]

It looks too high and too regular to be damp coming up. It would also be damp internally

I'd suspect sulphates from past use of the chimney causing more atmospheric moisture to be absorbed in that location. Pluming from the boiler flue would be contributing to cause almost permanent dampness to the external face

 

[rsi]

Thanks Woody. If what you say is true what would be a suitable remedy?

I think checking the drain and concrete is a good idea regardless, i've been planning on getting that concrete checked for a while and this would be a good excuse.

 

[Tipper]

Is the chimney still open at the top?

If no longer used it needs to be capped at the top, but still letting air ventilate it, to stop rain entering, and haven't we had a lot recently! Also an air vent needs to be inserted at the base to promote an airflow to ventilate it and stop damp.

It may be worth checking the fall on the boiler flue too which should be back towards the boiler so that any condensate collecting in the flue, and it will, can drain properly back through the boiler and out of the little white drain pipe leading into the drain below.

BTW the condenstate drain should be larger bore, say 32mm, outside to stop it freezing and faulting the boiler during really cold weather.

 

[dann09]

1. I'm in agreement with the sulpherisation possibility.
Altho the pattern of damp is odd.
FWIW: Why not open the metal plate by the flue terminal and have a look?
Can you peer up the chimney flue?

2. However, that external plinth and gulley have been there a long time -why? Presumably due to earlier damp issues.
The plinth is merely trapping moisture and possibly bridging the DPC, if one is in-situ. Is there a DPC?

3. Perhaps the boiler heat is attracting moisture esp. if that rear c/breast wall is a single skin.
3A. Is the elevation wall solid, or does it have a cavity?

4. There are no indications of structural or foundation difficulties.

5. As noted, the interior appears "dry" even with a solid floor, although the skirtings are not original.

Reviewing what i've written i'd say no. 1 suspect is sulpherisation, and no. 2 is a possibility of leaking drainage where the soil pipe enters the ground, and perhaps connects to clay/glaze.

 

[rsi]

Is the chimney still open at the top?

If no longer used it needs to be capped at the top, but still letting air ventilate it, to stop rain entering, and haven't we had a lot recently! Also an air vent needs to be inserted at the base to promote an airflow to ventilate it and stop damp.

It may be worth checking the fall on the boiler flue too which should be back towards the boiler so that any condensate collecting in the flue, and it will, can drain properly back through the boiler and out of the little white drain pipe leading into the drain below.

BTW the condenstate drain should be larger bore, say 32mm, outside to stop it freezing and faulting the boiler during really cold weather.

Cheers Tipper, the first thing we did (a year ago) was to get all the chimneys capped to avoid damp issues (we had some damp in another chimney because it wasn't capped), I think its vented, will take a look as soon as I can.

Im not sure what you mean about the fall on the boiler flue, but it sounds like your saying it should be pointing up so nothing falls on the wall? This is true.

 

[rsi]

1. I'm in agreement with the sulpherisation possibility.
Altho the pattern of damp is odd.
FWIW: Why not open the metal plate by the flue terminal and have a look?
Can you peer up the chimney flue?

2. However, that external plinth and gulley have been there a long time -why? Presumably due to earlier damp issues.
The plinth is merely trapping moisture and possibly bridging the DPC, if one is in-situ. Is there a DPC?

3. Perhaps the boiler heat is attracting moisture esp. if that rear c/breast wall is a single skin.
3A. Is the elevation wall solid, or does it have a cavity?

4. There are no indications of structural or foundation difficulties.

5. As noted, the interior appears "dry" even with a solid floor, although the skirtings are not original.

Reviewing what i've written i'd say no. 1 suspect is sulpherisation, and no. 2 is a possibility of leaking drainage where the soil pipe enters the ground, and perhaps connects to clay/glaze.

1> Ill try opening up the plate and taking a look, any idea on what I would be looking for?
2> I dont know why those things are there, there is a plant already that has cracked the concrete a little further up so I wanted to remove it and see what was gong on. There's another one on the other side of the house as well (I think it covers an unused storm drain but can't be sure).
3> I think its a cavity (sorry for my ignorance), when you say elevation wall...?
4> phew

I'm asking some drainage specialists to come out and quote me for lifting the concrete and generally telling me what they think so will keep you updated.

 

[dann09]

1. Just look for whatever damp or sooty/discoloured conditions exist.

2. What is covering "an unused storm drain"? Do you mean the plinth or the gulley? Why do you call it a storm drain? Try and determine where all your gulleys, soil and waste pipes, are draining to. Hopefully' they should drain thro a manhole.

It's a simple matter to remove the plinth and carefully open up around the grey soil pipe.

3. How do you know it's a cavity wall?
Your detached house has four elevations - front, rear and sides.

4. Perhaps post pics of any work in progress, and the location of the DPC.

 

[Alastairreid]

I would agree with woody on this one!

 

[rsi]

Thanks Dann09, I will do those things and post back tomorrow (xmas party tonight).

Thanks for all your help everyone so far.

 

[rsi]

Right sorry for the delay in getting back to you all, I thought I would get some builders round and drain specialists and see what they say. Nobody seems to know whats going on.

The drain specialists say that they would be happy to remove the plinth and checkout whats under but then never get back to me, they just seem to be interested in rising damp issues.

They did say however that they think the soil pipe goes out under the tarmac rather than down the side under the plynth.

Just a quick update I still need to answer some questions. (at work now).