[Closed] Damp proofing course advice needed

If it's a solid wall then none of them. Solid walls should use a lime plaster on the inside and either unrendered or lime render on the outside. Chemical DPCs don't work.

What he said.
Moisture management is the way, there was a thread on here recently "damp in stone building" or something

APF

Google _ yorkshire news rising damp in old houses its just a myth

Find where the water is coming down from.
Fix it.
Then don't worry.

Solid or rubble building?

Penetrating or rising damp?

Rainwater goods ok?

Relationship between finished floor level and outside ground level?

Then look at a cementitious tanking system if and where required and electro osmosis, assuming it is stone or rubble.

If it is brick, silicone injection with cementitious tanking if and where required.

All of the above re lime plus I you are still having problems dig a ground drain near footings, line with weed me brain and fill with graded gravel.

Keep pipes or trench. above 45 degree line to keep footing/ flag stones / whatever on compacted soil.

With old properties that have solid walls you manage damp rather than eliminate it.

The moisture is managed by absorption and evaporation. Water hitting the outside of the property will soak into the porous structure and will then be dried when the sun comes out and wind blows.

Similarly on the inside, condensation soaks into the walls and either migrates to the outer surface or is evaporated from the inner surface.

What happens is that instead of having porous coatings on the inner and outer walls such as lime mortar, people put non porous coatings such as cement and gypsum plaster. On the outside this initially seals the surface to prevent moisture being absorbed but it prevents condensation migrating out and worse still when it gets little cracks in moisture enters the structure but can't be evaporated out leaving a wet wall. (Think of wet sports kit left in your bag for a week).

On the inside moisture in the walls can't escape inside and be evaporated. This sits behind the plaster and blows it eventually. Also condensation will sit on the wall rather than be absorbed for later evaporation. A wet wall behind the plaster makes it worse as the wall is inevitably colder when wet than when dry.

Your inner walls are probably gypsum plastered or have had a non porous lining of wallpaper put on them. These need to be removed and a lime plaster finish used which will pass moisture through ("breathe" is a word used but it's not actual breathing).

On the outside optimally use a lime render if it's covered or lime mortar between the bricks if not.

Keep the levels around the house as low as possible. Get rid of solid paths that butt right up to the house to allow evaporation around the base of the walls. Sort out leaking gutters and this will also assist with evaporation.

Old houses are also not really compatible with modern heating methods and insulation requirements. You need ventilation and fires burning to get an airflow through the house that will aid the evaporation process.

A bit generic but old houses need old techniques which are often at odds with those that would be used on new houses. Nothing wrong with gypsum plaster and cement renders, just not on old places.

Hope that helps a bit (but probably confuses what was an almost settled issue!)

Rich.

PS - Tanking solutions and injection DPCs are contradictory to my approach of using breathable materials. They take the approach of preventing the wall gettng wet in the first place - in essence sealing in the structure behind impermeable coverings.
Whilst I don't personally favour these methods there will be people advocating this approach. I point this out not to trash other peoples views but to highlight that they are two very different approaches that a) don't work together and b) should be investigated so that you understand the pros and cons of both and you can make an informed decision as to one you feel will give you the best result given your circumstances.

PPS - lime is going to be the most expensive approach but probably the best long term solution. If it's a quick do up and you don't intend to be living there for an extended period of time then tanking will probably meet your short term needs.

Just my 2p worth and others are welcome to disagree.

Rich.

Oh dear. Ive just bought four tubes of drystone for my 1900 house. Has solid two skin wall with cavity. Do i use it?

No read the advice above

http://www.heritage-house.org/managing-damp-in-old-buildings.html

https://www.spab.org.uk/publications/old-house-handbook/