External refurbishment
A suitable external foam system needs compatible waterproofing and UV protection, including outlets, edges, upstands and penetrations. The foam is one layer within that system.
Commercial spray foam experts · Duratite Group
Commercial Flat Roof Spray Foam Insulation
Compare internal flat-roof insulation with external roofing foam systems, with moisture, drainage and the complete roof build-up assessed first.
Discuss your project →A specification built around your application
Flat-roof insulation is not one standard application. An external insulated roofing system and foam applied to an internal deck surface have different product, weatherproofing and moisture requirements. The starting point is a drawing or survey of the existing roof layers.
Identify the deck material, existing insulation, waterproof covering, falls, outlets and condition. Adding insulation changes the construction’s thermal and moisture behaviour. The chosen design needs to account for the full build-up rather than simply cover the most accessible face.
What shapes the insulation specification
Internal application
An underside proposal needs assessment of the deck, existing membranes and moisture risk. Do not assume that adding foam beneath any flat roof is automatically suitable.
Drainage and repairs
Falls, ponding, damaged coverings and wet materials influence the route. Resolve necessary repairs and specify how drainage and inspection access will remain functional.
Relevant project experience
Duratite project library
Dove Lane, Bristol
A roof project covering flat and pitched areas, with the insulation and external weatherproofing system described separately. See the preparation, foam application and completed finish.
Read the project case study →From project brief to installation
Share the brief
Send photographs, dimensions, site location and the intended use. Include known defects and the outcome you need, such as reducing heat loss or addressing cold-surface condensation.
Assess the construction
The survey establishes the accessible substrate, preparation, moisture conditions and practical installation scope. Drawings and existing records help resolve interfaces with other parts of the building or vessel.
Agree the scope and price
Compare the complete work package: preparation, insulation, protective finish, access and reinstatement. Agree responsibilities and the programme before the work begins.
Record the completed work
Arrange inspection before the insulation is concealed. Keep the agreed specification, product details and installation records with the asset’s maintenance information.
Understand commercial spray foam costs · Compare insulation approaches
Flat Roof Insulation questions
Can foam replace the waterproof covering?
External roofing foam needs its specified compatible weatherproof finish. An underside insulation layer is not a replacement for the roof covering.
Can you insulate a flat roof that already contains insulation?
The existing layers and their condition need assessment. Trapped moisture, membranes and the intended thermal upgrade influence whether an addition or a different refurbishment route is suitable.
What affects the cost of flat roof insulation?
The treated area, substrate condition, specified thickness, preparation, access equipment and finish all influence the price. Include the work programme and any removal or reinstatement in the enquiry so quotations cover the same scope.
What should be agreed before installation?
Confirm the product and application, prepared substrate, intended thickness, junction details, protective finish and access arrangements. Ask for the relevant product information, installation records and the specific terms of any proposed warranty.
Free survey
Get a quote for your project
Send us your building details and our technical team will specify the right system and a clear budget. No obligation.
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