The foundation coats applied before the topcoat.
A flat roof covered with roofing felt will normally have three layers of felt. The first two layers are called the underlay.
Strengthening existing building foundations, to remedy a problem with subsidence.
UPVC (unplasticised polyvinyl chloride) is a rigid plastic material widely used in the construction industry in the form of pipes, guttering, window and doorframes, fascias and soffits.