Houses are usually built with a damp proof course dpc just above floor level to prevent moisture rising up but if this has failed or the property did not have a.
Damp course above floor level.
External wall damp course is at door floor level.
Dpc material for situations where differential thermal movements occur.
Types of materials for damp proof course.
Selection of materials for damp proof course in buildings.
A damp proof course is a barrier usually formed by a membrane built into the walls of a property typically 150 mm above ground level to prevent damp rising through the walls.
Methods of damp proof course installation in construction.
Waterproof is defined by the astm as a treatment that resists the passage of water under pressure.
Tip 1 if a concrete floor is damp all over it is hard to isolate the moisture source.
Generally damp proofing keeps moisture out of a building where vapor barriers keep interior moisture from getting into walls.
Dpc above ground level.
Dpc material for floors roofs etc.
Damp below damp proof course level.
The external ground level must be 150mm below the damp course building reg the reason being that when rain fall hits the floor it will bounce up thus bypassing the dpc if it was level with the outside.
The third cause of damp is rising damp where moisture in the earth soaks through the foundations and walls of a house rising up through the layers or brick and causing damage.
Dpc material for cavity walls.
As it dries out the damp retreats slowly back to the points of ingress so if you are not able to see any isolated damp areas either ventilate and heat or shut all the doors and windows and use a dehumidifier.
Historically damp proof courses may have been formed using bitumen slates lead pitch asphalt or low absorption bricks.
A typical polymer damp proof course there are a number of alternatives to the modern dpc on a roll and these are sometimes found on older properties particularly those built prior to the second world war.
A reason that building regs dictate the 150mm below dpc rule is to reduce any rain splashing above the dpc level where there is most risk of damp bridging to inside.
A quick summary checklist.