A roof will only function well if it is designed and executed correctly. Quality control of both design and execution is important to minimise the risk of defects, failure, and damage. A design-specific checklist should be drawn up for use during design, design evaluation, and execution.
The checklists below may serve as inspiration but should be adapted to any given project and should, at a minimum, include the items below where failure is proven to result in material damage.
Does the roof have the required thermal insulation capacity?
Is the chosen roof covering suited to the specific roof slope?
Is roofing underlayment required? If yes, was it selected according to the DUKO guidelines, for example?
Do vent openings (if relevant) comply with Section 2.3, Roof Ventilation?
Do vent spaces (if relevant) have the correct height (45 or 70 mm)?
Is every part of the roof vented (resulting in an absence of ’dead’ areas)?
Is the structure resistant to ingress of driving rain, drifting snow, birds, and insects?
Are flashing heights adequate (i.e., typically min. 150 mm, depending on roof slope)?
Is the roof assembly resistant to moisture absorption of water vapour (e.g., by installing an effective or tight vapour barrier)?
If a moisture-adaptive vapour barrier is used, is the building classed as moisture load class 2 and have manufacturer’s conditions for use been met?
Are joints in structural parts, including vapour barrier, made tight (e.g., bonded across firm underlay)?
Have details relative to eaves, ridges, and crawl-spaces, penetrations, roof lights, dormers, and similar elements, been described and carefully checked?
Have steps been taken to ensure that no moisture can accumulate in the assembly?
Is the roof assembly safe against moisture absorption during construction (e.g., by covering it totally)?
Have sufficient moisture measurements been planned to document moisture conditions?