Cavity and weather resistance

Keeping water out of the cavity and out of the inner leaf: trays, laps, weeps and the clear width the cavity has to keep.

14 dimensions

Damp proofing and DPC

DPC heights, membrane laps and the junctions where damp proofing is most often bridged.

6 dimensions

Drainage and below ground

Gradients, cover depths, access spacing and trap seals for foul and surface water.

8 dimensions

Fire stopping and compartmentation

Cavity barriers, compartment lines and service penetrations. These are the details most often found short on site and the hardest to correct once boarded.

16 dimensions

Fixings and restraint

Tie spacing, restraint straps and fixing centres — the items that hold the structure together as one box.

8 dimensions

Services penetrations

Where pipes and cables pass through structure and fire lines, and the limits that apply when they do.

10 dimensions

Stairs and guarding

Rise, going, headroom, landings, handrail heights and the gaps guarding must not exceed.

9 dimensions

Structural spans and bearings

Bearings, notches, strutting and slab thicknesses for the load-carrying elements.

10 dimensions

Thermal and insulation

Fabric performance limits and the installation dimensions that decide whether the designed U-value is actually achieved.

3 dimensions

Timber frame

Sole plates, panel erection, breather membranes, tie fixings and the cavity behind the cladding — the numbers that decide whether a timber frame stays dry and stiff.

8 dimensions

Tolerances and setting out

Flatness, level and dimensional tolerances for finished work.

5 dimensions

Ventilation

Extract rates, purge areas, background ventilators and the void ventilation that keeps floors and roofs dry.

9 dimensions