1,000 sqm Flat Roof Replacement in Chessington, Surrey
Initial Assessment
C.F. Roofing was recently called to a commercial property in Chessington, Surrey, after the building suffered significant water ingress following heavy rain and thunderstorms.
We already knew the property, having carried out an urgent localised roof repair of approximately 100m² in 2019. That repair was undertaken to resolve an immediate problem for the client and covered only a small section of the building’s overall roof area, which extends to more than 1,000m².
In 2026, following a prolonged period of very hot weather, movement occurred within the existing roof structure. Expansion of the roof joists caused significant movement and dropping across the roof, which in turn resulted in the existing waterproofing system splitting and opening in numerous areas.
When heavy rain and thunderstorms subsequently arrived, water was able to penetrate through these newly formed defects, causing substantial water ingress into the building.
The consequences were particularly serious because an artist had paintings stored inside the property, some of which suffered water damage as a result of the leak. This made it especially important to identify the cause of the problem quickly and provide a reliable long-term waterproofing solution.
Inspection and Investigation
The client contacted C.F. Roofing the following day and asked us to investigate the problem.
Our inspection revealed numerous splits, openings and other defects across the existing flat roof covering.
The manufacturer of the existing roofing system also attended the property to assess the roof and advised that the original system had not been installed correctly.
With defects appearing across such a large proportion of the roof, further patch repairs would not have provided the client with a satisfactory long-term solution.
Following discussions with the owner and after showing him the extent of the deterioration, we were instructed to recover the entire roof area of more than 1,000m².
Preparing the Existing Flat Roof
Correct preparation is essential when installing a new waterproofing system, particularly across a roof of this size.
The existing roof surface was carefully prepared before being primed ready for the new waterproofing system.
A new underlay was then installed across the roof, with particular attention paid to laps, edges, roof details, penetrations and other vulnerable areas.
This preparation created a sound base for the new high-performance waterproofing membrane.
DANOSA High-Performance Waterproofing System
C.F. Roofing installed a DANOSA high-performance waterproofing membrane system across the entire roof.
The new system was applied systematically across the 1,000m²+ roof area to create a durable and continuous waterproof covering designed to protect the building from future water penetration.
Particular care was taken around joints, edges and detailing to ensure that the completed roof provided a reliable long-term waterproofing solution.
The Completed Roof
The finished project transformed a seriously compromised and leaking flat roof into a fully recovered and professionally waterproofed roofing system.
Instead of continuing to carry out individual repairs to an ageing and defective existing roof covering, the client now has a new waterproofing system protecting the entire building and its contents.
The new roof is backed by a 25-year materials warranty, together with C.F. Roofing’s 10-year workmanship guarantee against water penetration.
Commercial Flat Roofing in Chessington and Surrey
C.F. Roofing provides professional flat roof repair, refurbishment and waterproofing services throughout Chessington, Surrey and South West London.
From emergency repairs and isolated roof defects to complete commercial flat roof replacement and refurbishment projects, we can inspect the existing roof and recommend the most appropriate solution.
If your commercial or industrial property has a leaking flat roof, split roof membrane or ageing waterproofing system, contact C.F. Roofing to arrange an inspection and quotation.
