Preparing a roof for snow, frost and winter thaws

Deal with leaks, loose flashings and damaged drainage while the affected areas remain accessible. Some repair products require a minimum application temperature. Have the source of a leak located so the repair addresses the water path before snow conceals it.

Inspect areas disturbed by recent work. Antenna or equipment installation can leave unsealed holes, drilling swarf or scratches. Record the roof’s condition before winter so later damage can be traced to weather, installation or gradual wear. Arrange inspection with safe access.

During a thaw, water may reach a downpipe while its lower section is still frozen. A blockage at the outlet or a bend can cause overflow and ice below. Follow the entire route to the discharge point, including concealed sections downstream of a clean-looking gutter.

Chipping ice out of a gutter can puncture it and exposes the worker to a fall at the eaves. If trace heating is being considered, have the electrical system selected for the gutter material and site conditions. Correct inadequate falls or insufficient drainage capacity separately.

Depth must be considered together with moisture content, snow type and underlying ice. Drifts near parapets, changes in level and equipment cause uneven loads. Refer to the structural design for the individual building when assessing accumulation. A single depth threshold cannot cover all roofs.

On a large roof, assign monitoring points and responsibility for deciding when to act. Include the areas where drifts form and the clearance method. Moving snow into piles on another part of the roof can overload that area even while the cleared section is relieved.

Winter temperature differences make air leaks and condensation easier to detect. Look at connections from the loft and check how moisture can escape. Let wet areas be investigated before covering them. Maintain room ventilation so humid indoor air does not enter the roof through unintended gaps.

For PIR and other insulation, inspect continuity at wall plates, windows and penetrations. Identify ventilation channels on the design before filling a void. A repair should restore the intended sequence of layers in both metal-sheet roofs and insulated panel assemblies.

Map the access route, fall-protection anchor points and rooflights before snow hides them. Clearance crews need training, suitable equipment and information on the roof structure. Include the exclusion area on the ground where snow or tools could fall.

Choose a method that protects coatings, flashings and translucent panels. Sharp tools and attempts to break up ice can cause damage. On insulated roof panels verify allowable local loads as well. A panel rated for distributed snow load may have restrictions on foot traffic.

Unusual deflection, fresh leaks or changes in structural behaviour need prompt assessment. Keep people away from the affected area and bring in qualified help. Identify a contact for building users to report observations and a responsible person to decide on continued use.

After winter, inspect the covering, drainage and fasteners. Record where drifts lasted unusually long or ice formed repeatedly. Use those observations to update the next winter’s inspection points, maintenance work and arrangements for responding to severe conditions.