New extension floor and walls still damp

[Ben23]

Had a new single story extension built. It's got a concrete floor and block inner wall.

It was made watertight at the beginning of March and heating installed at the start of April. It had DPM and insulation installed and passed off by BC.

The floor is still very damp in places and the bottoms of the walls are too, to a height of around 3 inches. Its drylined and some of the plaster board at the bottom near the floor is showing signs of mould.

Is this normal and will it dry out? Are there any precautions I should take before getting kitchen installed? Eg apply slurry on floor wall joint and use dpm underlay under cabinets.

Everything did get soaked several times during construction including the floor, bricks and the wool insulation in the walls.

 

[^woody^]

Walls should be protected when being built, salts can be bought out when drying leading to detrimental effects. Soaked insulation reduces its effectiveness.

It will dry eventually. You need the doors and windows opened, and a draught.