Why do flat roofs leak at the seams and edges?
Because they depend on joints, not on slope. Water that cannot run off will find a gap, and seams, edges, penetrations and drains are the weakest places. Heat, cold and movement open them, and standing water speeds the damage. Regular checks catch failures while they are small.
A membrane expands and contracts over the seasons. Over years, the adhesives and tapes tire and the edges lift.
Cleaning drains and checking seams each spring and autumn is the cheapest maintenance there is.
What does ponding mean, and is it a problem?
Ponding is water that stays on the roof for a day or more after rain. A little is normal on some roofs, but frequent or deep ponding adds weight, speeds membrane wear and can point to sagging or a blocked drain. A roofer decides whether it needs a fix.
In winter, ponds freeze and thaw and put stress on seams. A roof that holds large ponds under snow carries more load than it was designed for.
How much snow can a flat roof carry?
That depends on how the building was designed. Connecticut ground snow loads are commonly cited in the range of 30 to 50 pounds per square foot, with higher figures in the northwest hills, but a Sherman value is not given here. Ask the town building office or an engineer if you are worried about a heavy load.
Signs of overload include doors that stick, new ceiling cracks and sagging roof lines. If you see them, keep people out and call a professional.
Do not shovel a flat roof without advice. A shovel can slice a membrane.
What maintenance keeps a flat roof working?
Clear the drains and scuppers, remove leaves and debris, look at seams and flashing twice a year, and fix small splits before they spread. Do it in spring and autumn and after major storms. A roofer can do this safely, and a record of each visit helps you spot slow changes.
Most flat roof failures begin as small, ignorable defects: a lifted seam, a split at a corner, a clogged drain. Water then does the rest, especially through a freeze and thaw cycle.
On wooded lots, leaf fall is the main hazard. Ask for a visit after the leaves come down and again once the thaw ends. Keep foot traffic to a minimum, since equipment and boots can puncture a membrane.
- Clear drains and scuppers in autumn and spring
- Look at seams, edges and flashing
- Remove debris and any standing water causes
- Keep records and photographs of each visit
