Flat roofing · A focused guide
What should a proposal to cover over an existing flat roof explain?
Published by Big Ben Roofing Ltd
An overlay proposal should identify the layers being retained and explain why they are suitable to remain within the new roof assembly. It should also address the effect on edges, outlets, wall connections and openings. Ask how the existing condition was established and what findings would change the approach. Covering over the roof is not automatically suitable or unsuitable; the decision needs to relate to the assessed build-up and the complete proposed detail, rather than the new surface alone.
Request a named retained build-up
Ask whether the existing covering, insulation and deck have been identified and which parts remain uncertain. A short description saying over-roof does not explain those assumptions. If further investigation is needed, establish when it happens and how its findings affect approval of the proposal. Keep any suggestion of concealed moisture separate from a confirmed observation until appropriate assessment supports it.
Compare the connections after the added layers
The completed assembly must be considered as a whole, including the relationship to rooflights, walls and drainage. Ask the professional to explain changes at those interfaces and any work required to retained components. Compare an overlay option and a removal option on their full scopes, access and unknowns rather than treating the difference as only the price of disposing of the old covering.
Useful details to record
- List the layers the proposal intends to retain.
- Ask how their condition and identity were established.
- Check the treatment of edges, openings and drainage.
- Agree which findings would require the approach to change.
Use information already available from indoors or ground level. Do not climb onto the roof or disturb materials to complete this checklist.
Does an overlay quote include repairs to anything found underneath?
Only the agreed scope and allowances establish what is included. Ask how concealed defects would be investigated and approved, particularly where the proposal retains layers. Do not assume a new covering quotation includes unlimited supporting repairs or confirms their absence.
Background reading
General guidance helps frame the questions. The cause, suitable materials and scope depend on inspection of the particular roof.
Related questions
Can a flat roof quote confirm the deck condition without opening it?
Separate visible roof findings from concealed deck assumptions and agree how further investigation or renewal allowances would be handled.
What should be checked where a flat roof meets a wall or doorway?
Discuss fixed heights and adjoining wall or doorway details before accepting a covering renewal or a change to the flat-roof build-up.
Discuss what you have noticed
Include your postcode, the affected roof section and when the concern appears. The team will review the enquiry and confirm the next step, scope and availability.
Request a roofing assessment