External wall insulation: what a good survey should cover

A homeowner-friendly guide to wall condition, junctions, services, moisture and finish choices.

Wall construction and condition

The survey should establish what the external walls are made from, whether they are dry and stable, and how previous coatings may affect adhesion and moisture movement.

Junctions and projections

Insulation changes the wall thickness. Roof overhangs, sills, vents, gas boxes, pipes, lights, boundaries and paths all need a deliberate solution.

Moisture and ventilation

Existing damp defects should be resolved and ventilation must remain effective. A thermal upgrade should form part of a coherent building strategy.

Fire and system requirements

The proposed products, fixings and detailing must reflect the building type, height and applicable requirements. Complete tested system components should be used together.

Appearance and permissions

Colour, texture, elevation changes and boundary impacts may require planning or other approvals. These should be checked before the programme is fixed.