Damp Proofing

[Carriage-house-revival]

Hi all,

Glad to have found this forum.
I have a question about damp for a property (1820s) that my wife and I are buying.

Two independent damp surveys done now - both recommend an injected DPC and salt resistant tanking plaster up to 1.2m on all exterior & interior walls. Obviously at significant cost. Both say that the old DPC has failed and has also been bridged by high ground levels.

However, neither cover the remedial things that need to be done e.g the ground level is too high, the guttering is shot, drainage is poor.

Now my initial thinking is to rectify the ground levels and install french drains around the perimeter property and allow the walls to dry out over 6-months or so before retesting and going from there.

We also want to extend the property and I’m a bit concerned about putting my chips down on breathable materials with the new extension and the junctions against the old house, if eventually we might end up down the tanking & dpc route.

 

[stuart45]

Firstly, an 1820's is unlikely to have a DPC.
You are correct to want to rectify the source of the dampness first.
Don't worry about building an extension, as there are construction methods to blend in new with old.

 

[Itchinfilth]

Ignore their recommendations like the plague. You are already on the right tracks with your suggestion to lower external ground levels, sort drainage as needed and rainwater goods and remedying the issue at source. What type of construction is it and is it rendered etc?

 

[Carriage-house-revival]

It’s solid wall - brick construction. No external render but does have some dodgy pink paint on the exterior which I suspect is non breathable

 

[Itchinfilth]

I think stick to the plan mentioned above and see how it goes. If you search "zebcolm" on here you'll find another option for drainage. I used it to great success from advice here after I bought a damp property!

 

[Matt Green]

Remove the masonry paint, lower the ground levels and see what it looks like in a year's time.

Very few people sell a product called 'leave it alone and let it dry out' and so it doesn't get as many recommendations as it should.


M.