Offices, shops, warehouses and industrial units often have very different roofs from houses. They tend to be larger and flatter, with membranes or metal sheeting, rooflights, plant, box gutters and access issues. A leak can disrupt a business, damage stock and affect tenants.
This guide explains what a commercial roof survey looks at and the main things to know about access and safety.
Flat roofs on commercial buildings
Many offices and shops have flat roofs finished in felt, asphalt, EPDM rubber, GRP fibreglass or single-ply membranes. Common faults include ponding, blistering, splits, failed seams and damaged upstands. Plant such as air-conditioning units, and the people who service it, can also damage a membrane over time. Larger roofs also suffer from deflection, where the deck sags and water collects. Checkatrade gives typical lifespans of around 15–20 years for felt, 30–50 years for EPDM and up to about 30 years for GRP (Checkatrade flat roof guide). See our guide to flat roof problems.
Metal sheeting and cement sheets
Industrial units and warehouses often have profiled metal sheet roofs. Problems include corroded fixings, cut-edge corrosion along sheet edges, failed laps and loose sheets. Older buildings may have cement sheet roofs. On a building from before 2000, these could contain asbestos. Our report flags such materials and says a specialist asbestos surveyor should check them before they’re disturbed. See asbestos cement roofs.
Fragile rooflights
Rooflights let light into warehouses and units, but many are fragile. Older plastic rooflights become brittle in sunlight and may not take a person’s weight. Cement sheet roofs can be fragile too. Falls through fragile roofs and rooflights are a serious risk, and staff and contractors should never step onto them without proper safety measures. We don’t walk on fragile roofs. We inspect them from safe positions and, where applicable, by drone.
Want a roof surveyed? We cover London and the South East, with written reports and photos from £150 including VAT. Book a survey or call 07833 053749.
Gutters and drainage
Box gutters and valley gutters on commercial roofs carry large volumes of water. If an outlet blocks, water can overflow into the building. A survey checks gutters, outlets, overflows and downpipes as far as can be seen. Our gutter survey covers above-ground rainwater goods only, not underground drains.
Access and planning the visit
Commercial roofs often need a plan for access. Useful things to tell us when you get in touch:
- the type of building and roof, if known
- whether there’s a roof hatch, door or fixed ladder
- whether there’s edge protection
- any known leaks and where they show inside
- who will meet us on site.
A commercial roof usually takes about 3–4 hours on site. Larger or more complex roofs take longer. Drone flights depend on the weather and airspace rules. Some business areas, such as the City of London, have drone restrictions. See drone rules near airports and in central London.
What you get
A written report with photographs, describing the roof’s condition, defects and recommendations prioritised by urgency. Many owners and managing agents use it to plan maintenance budgets and to brief contractors so quotes cover the same work. Our flat roof survey starts from £150, including VAT, with larger commercial roofs quoted. Our case studies include a flat roof survey on a five-storey office building in Camden.
Quick answers
Can you survey a roof while the business is open?
Usually, yes. We plan the visit with you so it causes as little disruption as possible.
Do you inspect rooflights?
Yes, from safe positions and by drone where applicable. We don’t stand on or near fragile rooflights.
Can you find leaks in a commercial flat roof?
A roof leak investigation traces where water is getting in, and electronic leak detection can test suitable membranes.
Related services
More advice
- Flat Roof Problems: Ponding, Blisters and Splits
- Asbestos Cement Roofs, Garages and Soffits
- Roof Surveys for Landlords and Block Managers
- How Electronic Leak Detection Works
- All advice
This guide is general information about roofs and roof surveys. It isn’t legal, insurance or structural engineering advice; for those, speak to a suitably qualified professional.