New roof installations · A focused guide
What should a new roof brief say about insulation and ventilation?
Published by Big Ben Roofing Ltd
The brief should identify a coordinated roof assembly rather than list a covering and leave insulation or ventilation to separate assumptions. Ask who specifies the layers, their position and the connected details, and which work the roofing contractor provides. Moisture considerations depend on that complete design and the building below. Share the intended use of the space and current drawings, but do not select or alter concealed layers from generic online advice or expect a material list to replace professional design.
Explain the space the roof encloses
A roof over an occupied extension and one over another type of structure may start with different design requirements. Give the project team the intended use and the information already specified, marking any uncertainty. SPAB's insulation guidance shows why moisture and ventilation need consideration together, particularly in existing traditional buildings. A new connection to older construction should therefore be explained within its actual building context.
Allocate responsibility for the complete build-up
Ask for a drawing or written specification showing what is installed by each trade and how continuity is achieved at walls and openings. If the design changes, identify who reviews the assembly before instructions reach site. Avoid substituting an extra vent or an additional layer as an informal solution without understanding its role. The agreed quotation should distinguish installation from any design work still required.
Useful details to record
- State the intended use of the space below.
- Provide the current roof assembly specification if available.
- Name the person responsible for coordinated design.
- Ask how walls and openings connect to the assembly.
Use information already available from indoors or ground level. Do not climb onto the roof or disturb materials to complete this checklist.
Should every new roof use the same insulation arrangement?
A suitable assembly depends on the roof form, building use, adjoining construction and project requirements. Ask the responsible designer to specify it for the actual proposal, with installation boundaries made clear. A generic layer sequence should not be assumed suitable for every roof.
Background reading
General guidance helps frame the questions. The cause, suitable materials and scope depend on inspection of the particular roof.
Related questions
What should be reviewed if roof moisture appears after insulation work?
Report the timing of insulation changes and roof moisture without moving materials or assuming either a rain leak or a ventilation diagnosis.
What should the roofer and builder each provide on a new roof?
Set out trade interfaces for supporting construction, roof layers, openings, drainage and protection before a new roof programme is agreed.
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.
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