Waterproof render, or Lime plaster?

[luvdiy]

First I have to say just reading the Damp forum has really taught me a lot, our house has the signs of rising damp, blown plaster, salt crystals brown watermark. I know it does not have a DPC, it is a really old cottage. The damp has got worse since we converted from coal fires to electric central heating. I have been told it should be replastered with Lime plaster to let the brickwork breath. Or would you go for waterproof render. I have done rendering before, are there any special precautions or tips for lime plaster?

Thanks a hod full
luvdiy

[Sir Harry]

Whilst lime plasters will allow the wall to breathe, and moisture to more easily evaporate, they also allow significant take-up of ground salts.

In order to prevent salt contamination, lime plasters are considered unsuitable for walls that are suffering from rising damp or for walls that are in the process of drying out following installation of a dpc.

[luvdiy]

Thanks for the advice, I can rule lime plaster out now.

[thescruff]

What material is the building constructed with.

[leebwk]

Hi,

I would get the dpc sorted first before any rendering or plastering

[ccfc_soulcrew]

use a bwpda registerred damp proofer to cary out the dpc injection works
if your property is of stone construction then a lime based renderd will be ok but if it's red brick personaly i would go for a sand and cement render
with waterproofer and feb to a three to one ratio but whatever you do leave a minimum of a one inch gap between the lime/render finish and any solid floors
i work for a damp proofing company and this is bwpda spec
if you need any more help look up the bwpda web site there is lots of info there for you

[Sir Harry]

Do not take the plaster down to an inch from the solid floor! Take it down to a level that is just above the dpc. If you take the plaster down any further the dpc will be bridged and rendered ineffective.