Damp in basement room

[TonyV]

Having redecorated our basement flat in a converted 1830s Georgian House in London, I think there maybe some damp in the walls, before I get companies in to look at it and quote, is there a general rule of thumb price per linear meter for installing an injected DPC. I realise that the plaster will need to be taken off to a metre above ground level and made good afterwards. Do you think companies would be adverse to my taking the plaster off and arranging making good, so that their only responsibility would be injecting the DPC.
Thanks in advance
Tony

 

[JohnD]

Does this house have an "area" or are the basement walls, above floor level, in contact with the earth?


p.s. I don't think dam proofers will mind you doing the replastering, they'll just say any subsequent damp isn't covered by their guarantee.

 

[TonyV]

Thanks John for quick response...Yes there is an area. But the damp appears to be on the party walls. Spoke to a friend earlier who may be able to get me a professional damp meter for an evening to play with.
Thanks again
Tony

 

[Moz]

TonyV
you can "tank" the walls yourself then plaster over it , jobs a good one

 

[TonyV]

can " tank it " know how 2 do that and can do it - or know a man that can - What happens 2 moisture? must come up somewhere- it will only wick higher? I don't Know - that's why i'm asking
Tony

 

[Frederick]

You could tank it with something like Vandex which you can get from bigger builders merchants. Basically you just hack off back to the brickwork, remove any dust and trowel it on. It make any damp wick higher up the wall, but it would be extremely unlikely to rise over 2m, so you should be OK as long as you tank to full ceiling height.

From what you say, rising damp is the most likely explanation, so such drastic action may not be necessary. Dividing walls in basements do not often have DPCs as basements were not usually intended as living space. If you have rising damp you will need to inject a chemical DPC and replaster with a sand:cement mix with a salt-resistant additive.

For information on diagnosing which type of dampness you have, Graham Coleman has a very informative page on his website explaining the correct use of moiture meters: http://www.buildingpreservation.com/Use of moisture meters .html

 

[JohnD]

Don't mention Rising Damp

 

[Frederick]

Rising Damp, Rising Damp, Rising Damp. There, I got it off my chest. I have spoken the phrase that dare not speak its name.

Discounting those strange people who believe rising damp to be some kind of conspiracy theory, I think it is clearly the most likely explanation in this situation. The only other likely candidates are condensation and penetrating damp coming from the ground into the dividing wall (a kind of sideways damp). Condensation is unlikely as you would expect to also occur on the earth-retaining walls (which tend to be colder).

Now I'm off on holiday for two weeks. However, I expect there will be more fascinating discussion on the true meaning of rising damp on these forums when I return.