The issue I have is noise caused by ice cracking on the flat roof.
– Gary, Oakville

Does Avenue Road Roofing install heat tracing systems on flat roofs? If so, I would like to arrange an estimate. The issue I have is noise caused by ice cracking on the flat roof.

Craig’s response – “the best solution is periodic snow and ice removal”

The ice is likely the result of ponding of water on your flat roof. Flat roofs that have good drainage are less likely to experience this problem.

You could arrange to have your flat roof inspected by one of our roofing experts. Another approach would be to request periodic snow/ice removal during winter months.

It is not recommended to install heating cables directly on flat roofs. Here’s why:

• Flat roofs will hold residual water. In the event there is a short or break in the cabling, a shock hazard is likely
• Cables will not generate enough thermal heat to handle frozen ice buildup
• Securing heating cables typically involves cleats and these cleats cannot penetrate the flat roof’s membrane. Cables can be used at the base of a sloped roof, where it adjoins a flat roof. They can also be used in the trough /downpipe system surrounding a flat roof.

Follow up question by Gary from Oakville

Thank you for your reply to my enquiry regarding heating cables on flat roofs. As a follow up I wonder if you could comment on whether it is possible to improve the drainage of a flat roof to eliminate the ponding and ice build up or whether I am faced with replacing the entire roof. Any thoughts you have would be appreciated.

Craig answers Gary’s follow-up question

No problem. My pleasure. If your flat roof is a tar & gravel system and it is in good condition or reasonably new, you can try adding gravel (3/8" pea gravel) to the low spots
on the flat.

You can determine the low spots by going up after a good rainfall and see where the water lies. The other method is to use a string line at several junctures (corner to corner, from the drain to the edges, etc.). Make sure not to let gravel down the drain if it is an internal roof drain (like your bath tub).

If it is a modified bitumen (rubber), or EPDM system you must improve drainage as described below.

The ideal scene involves replacing the roof and incorporating a tapered insulation system, designed to achieve positive drainage or to have wood purlons tapered to account for proper drainage and re-sheeted using 3/4" plywood. Purlons should be 16" on centre. Your new water proofing membrane would then be installed (either modified bitumen membrane system or B.U.R. system). If you go the carpentry route, realize that modifications to perimeter fascia boards may be necessary.

As I have not viewed the roof, it is difficult to suggest which approach will be more cost effective.

One advantage of going the insulation route is that you could apply for eco-ENERGY grants, which could offset your costs by $1,100.