Damp Challenge

[SD]

Here's one for you- A friend of mine lives in an 19thC unrendered stone cottage. Most original plaster etc still in place. The cottage is on the roadside, next to a brige crossing a river. A 'utility room' has been added on the riverside of the cottage and it is suffering from a lot of damp, as it is built against the earthern bank leading up to the bridge. They want to make the room more habitable. How can they address the damp? Obviously they can't remove the source of the damp as the earthern bank relates to the bridge. A builder has suggested dry lining in the modern way, but they wonder if it is better just to lime wash the walls and heat the room. What would you suggest?

 

[Moo]

When was the utility room added?

 

[Penners]

As this utility room is new, I'm not sure there's much value in limewashing it.

Is the wall of the utility room actually in contact with earth above the DPC (I presume it has a DPC)? If so, is it possible for them to cut a trench between the wall and the earth?

It's also possible that condensation is a significant factor in the dampness of the room. The fact that it's a utility room implies the use of a washing machine, perhaps a tumble dryer, and other wet processes. The air beside a river is likely to have high humidity which will exacerbate the problem.

Warmth in the room will help, but only if it's also well ventilated. Ventilation is vital.

 

[SD]

To describe it as a 'utility' room, makes it sounds all modern and shiny. I think the previous owner added it on and he constructed it out of boulders procured from the river and but I don't know if he used lime or cement mortar, but I doubt it has a damp proof course. The bank is almost one story high and I don't think it is possible to cut a trench between the wall and the bank, I think the bank is something they have to live with. At the moment the room only has access from outside and they are just using it as a store but they want to change it to a utility room in the future which makes your point about ventilation important.

 

[SD]

Given that they can't remove the source of the damp, do you think the best thing to do is just to keep the room well ventilated and 'dry line' the walls to create a relatively 'dry room' within the structure?

 

[NT]

A dehumidifier is a lot cheaper than extra heating or venting. Its also an instant way to get ok RH. Must be humidistatic though, else can cause problems.


NT

 

[stickybeak]

.

 

[SD]

Thanks for these replies. This is great. oh -a vertical damp proof course. I didn't know about that. I definetly think this could be a solution for them. (yes the wall is unrendered both sides). Stickybeak thanks for that link, thats my bedtime reading sorted out. I wonder if my national park provides such an essential document??? Great handy hint, I'll pass it on. I'll talk to my friends more about the type of damp problems they have for some more info. Many thanks though so far.

 

[Nemesis]

If the place is unheated then damp will be worse of course - but are the walls running with it, requiring a cavity and pumped system, or are they simply damp? Some of that could be condensation.

 

[Matt Green]

Dear people who have found this link whilst searching the achives:

http://www2.valeroyal.gov.uk/internet/vr.nsf/0/E2949E8606E79785802570920032159A/$file/historic_and_listed_buildings.pd f

The bit about damp is pretty good, but the timber decay section is shockingly inaccurate. Please consult a different source.


Matt

 

[Nemesis]

Such as Matt Green?



PS all www. links seem to have been culled from posts and need to be replaced via the profiles bit of the site.

 

[Matt Green]

Not necessarily Nemesis, not necessarily:

http://www.amazon.co.uk/Surveying-Historic-Buildings-David-Watt/dp/1873394160/ref=pd_bbs_sr_1/026-9617941-4722857?ie=UTF8&s=books&qid=1175007300&sr=8-1

http://www.amazon.co.uk/Survey-Repair-Traditional-Buildings-Conservation/dp/1873394500/ref=sr_1_6/026-9617941-4722857?ie=UTF8&s=books&qid=1175007536&sr=1-6

http://www.amazon.co.uk/Building-Mycology-Management-Health-Buildings/dp/0419190201/ref=sr_1_1/026-9617941-4722857?ie=UTF8&s=books&qid=1175007595&sr=1-1

and, well, maybe this one:

http://www.amazon.co.uk/Timber-Buildings-Treatment-Conservation-Practitioners/dp/0419188207/ref=sr_1_1/026-9617941-4722857?ie=UTF8&s=books&qid=1175007666&sr=1-1


There's lovely.


Matt.

 

[Nemesis]

And all at bargain prices too - how thoughtful.

 

[davidm]

Hello there - I'm the friend SD was talking about so I thought I'd fill in the details of the problem. The "utility room" is an annex to our stone cottage that was built probably about 80 years ago. It was the room used to salt the pig in early years and as a wood storage in later years. The walls are thick thick stone with a rubble filled cavity. The room is not at the same level as the rest of the house with the floor level of the main room about half way up the wall of the utility room.

As the house is on a slope, two of the walls are external. The third wall is partly external (half the vertical wall) but also has the walled off soil of the front garden against the other half. The other wall has the earth under the living room against the lower third, the cavity under the floor and then the living room against it. Difficult to explain!!

Bottom line of it is that a significant part of the wall is against earth that is under the main part of the house hence drains etc are impossible.

The floor is concrete but anything but level and is probably just concrete over bare earth.

The solution we are thinking off is to dig up the concrete floor and relay with a limecrete floor to allow it to breathe and then to strip the gloss paint off the stone walls and just limewash. Then put in a radiator and put heat into the room for the first time, accept that it will always be a bit damp. I suppose we aren't thinking of a damp proof is that could just divert the damp into the void under our living room floor so it is better not to seal the damp into the wall at all.

Any advice greatly taken!!

 

[NT]

Sounds like an ideal case for a dehumidifier.


NT

 

[MdB]

Two main choices - Try and stop the moisture getting into the room or let it in and then evaporate away as easily as possible.

The first option generally involves tanking which won't be good for the wall but may work for a while at least. Unfortunately, in old properties it is likely to fail due to movement and then you get a large volume of water through a small area which cause obvious damp.

Your solution is to allow the water in over the largest area possible which allows the most amount of evaporation which will keep it as dry as possible. It will require ventilation though as the moisture has to escape out of the room somehow. An alternative is a dehumidifier which NT will tell you all about.

The option you haven't mentioned is to dry lining. If the walls are still damp then you can dry line the walls so as to give a more pleasant surface. However, if you are going to do this, ventilation for the cavity generated should be included. I've just started removing the dry lining from one wall in my house and its not very pleasant behind it as no vents were installed. The one section that did have a vent (needed for the gas fire) was fine behind it but the rest were very mouldy and the plaster board was failing at the wettest point at the bottom.

 

[davidm]

Just an update on this. I stripped off all the plaster on the walls and repointed with lime, dug up the concrete floor and put a limecrete floor in and finished it with flagstones. It is a great room now and with leaving the window open in the summer and radiator on in winter, we have had no damp problems.

 

[MdB]

Thanks for the update. Its great to hear a success.

 

[Penners]

Well, I think you've done really well to achieve all that in four months.

It'll be interesting to hear your thoughts on how it behaved over the winter. Will you let us know?

 

[Nemesis]

OP was 2007, so possibly not four months.