Why do flat roofs leak more than pitched ones?
A flat roof relies on a continuous sealed membrane and sheds water slowly, so standing water sits on any weak spot. A pitched roof overlaps shingles and drains quickly. Seams, drains, edges and penetrations are the usual weak spots, and each one has to stay sealed through every season.
Water that sits is water that gets time to work. A small gap that would dry out in an hour on a sloped roof can soak in over a day on a flat one. Ponding also adds weight and speeds up the wear on the surface.
Movement matters too. A low-slope roof expands and contracts with every freeze and thaw, and the membrane, the seams and the flashing at walls have to move with it. Warwick's cold season runs about 3.3 months, so a roof that survives one winter has been tested hard.
Should I patch the roof or replace it?
A patch suits a single failure on a membrane that is otherwise sound. Replacement makes sense when the surface is worn, blistered or leaking in several places, or when the layers underneath are wet. A roofer should show you the damage and explain which one your roof needs and why.
Patch after patch is a sign the whole surface is aging. Roofers often say it is worth looking at replacement when repairs start to cluster or when more than one spot leaks in a season. Wet insulation under the membrane also tips the balance, since it has to come out either way.
If you are weighing options, ask for the repair and the replacement quoted separately, with the roofer's reasons. Never feel pushed to replace a roof that a patch will hold, and never accept a patch on a roof that is plainly finished.
How does snow affect a low-slope roof?
Snow sits on a nearly level roof instead of sliding off, so it stays longer, melts slowly and can pool as water behind drains that are iced up. Blocked scuppers and drains in winter push meltwater against walls and seams. Keeping drains clear before the cold season is the simplest step.
Warwick gets about 32 to 37 inches of snow a year, and a flat roof keeps what falls on it. A drain choked with leaves in November is a pond by February. Meltwater that cannot drain has only one place to go, which is under an edge or up behind flashing.
Do not chip at ice or snow with a shovel or a tool. A membrane is thin, and a cut from a shovel edge is a leak waiting to happen. A roofer can clear snow safely if it is a concern, and roof inspection is a sensible visit before winter.
Does the number of apartments in the building matter?
It can. In Rhode Island a Commercial Roofing License applies to buildings with four or more dwelling units, while residential roofing is covered by Contractor Registration. A three-family house sits on the residential side. Ask any roofer what they hold and check it with the board.
The Contractors' Registration and Licensing Board sorts the two by the number of units. If you own a building with four or more apartments, ask the roofer whether they hold the commercial licence, and check it with the board directly. Our guide to hiring a roofer in Rhode Island covers what to ask.
In Massachusetts towns like Fall River, Swansea and Somerset, different rules apply, with Home Improvement Contractor registration for one- to four-unit owner-occupied homes. The roofer you are connected with can tell you how it works for your address.