Flat Roof Installation
An inch of standing water weighs about five and a quarter pounds on every square foot it covers. Spread that over a thousand square feet of roof and the puddle nobody worried about is more than two and a half tons sitting on the framing. That single arithmetic is the reason a flat roof installation is really a drainage installation with a waterproof surface attached. APC Roofing installs low-slope roofing for homes and small commercial buildings in Florida, Colorado, Kansas and Missouri, from a porch deck to a full field.
Nothing goes down until the deck is right
Soft sheathing, rusted steel, loose fasteners, delaminated board and old wet insulation get found and dealt with before a roll is opened. Fasteners need something solid to bite; without it the roof loosens in the first strong wind, and no membrane compensates for a substrate that moves. On a re-roof this is also where the honest choice between covering the old system and taking it off gets made. Removal costs more on day one and is often the only version of the job that produces a roof worth what it costs.
Building the slope that was never there
Low-slope roofs are expected to shed, not hold — a quarter inch of fall per foot is the design target manufacturers and codes work from. Most existing buildings do not have it, so it gets built with tapered insulation: panels cut on a pitch and laid to a layout drawing that walks water toward the drains. Small crickets go behind curbs, chimneys and anything else wide enough to dam a run. Done properly, the roof is dry two days after a storm rather than holding four separate ponds until the sun gets to them.
Primary drainage, and the drainage for when that fails
Drains, scuppers and gutters are sized for the rainfall the building actually gets, not the national average. A short violent cell can put more water on a roof in twenty minutes than a grey all-day rain delivers by dusk, and an undersized outlet does not care how new the membrane above it is. Where a parapet wall means water cannot simply run off the edge, a secondary path is required: an overflow drain or scupper, with its inlet set no more than two inches above the low point of the roof, so a blocked primary drain produces a visible waterfall down the wall instead of an invisible load on the structure.
Edges, curbs and the order of the days
The open field is the easy part. Pipe boots, equipment curbs, wall terminations, skylight kerbs and the transition where a low-slope section meets a pitched roof are where installation skill shows and where the leaks start. Edge securement earns particular attention, since wind lifts a roof at its perimeter and corners first and works inward from there. Good crews open only what they can close in and seal before the light goes, which is what keeps an unexpected evening storm outside the building.
Houses have flat roofs too
Over a porch, a garage, a dormer, or a room addition that never had the pitch for shingles — these small areas cause outsized trouble, usually where they tuck under siding or die into the main roof. They deserve a proper membrane and a properly flashed transition, not roll roofing and a tube of sealant. Built at the scale the house calls for and tied correctly into the pitched roof above, they stop being the part of the house you think about every time it rains.
