Commercial Skylights in Troy, MI

Many warehouses and retail boxes use unit skylights: a factory-made frame and plastic dome set on a curb. On a roof flatter than 3:12, the building code requires that curb to lift the skylight at least 4 inches above the roof surface. The membrane runs up the curb and is flashed under the skylight frame.

Repairs fall into three sizes. A dome that has pulled loose from its frame can be resealed. A dome that has gone yellow, brittle or cracked can be replaced on its existing frame if the maker still supplies one. A frame that leaks at its corners, or a curb that has rotted, means a new unit and new curb flashing. When insulation is added during a reroof, an old curb can end up nearly flush with the new surface, so ask whether the curbs need raising.

Office atriums, lobbies and older plants often have framed glass skylights instead of plastic domes. Glass brings its own rule: annealed, heat-strengthened, tempered or wired glass needs a retention screen underneath that can hold twice the weight of the glass and sits within 4 inches of it. Laminated glass doesn't need the screen. When old wired glass is being replaced over a walkway, pricing laminated units next to tempered units with screens is a fair comparison to ask for.

A building four or more stories tall needs a stairway to the roof, unless the roof is steeper than 4:12. Where nobody occupies the roof, the code accepts a roof hatch of at least 16 square feet, with no side shorter than 2 feet. If that hatch sits within 10 feet of a roof edge with a drop of more than 30 inches, the code also wants a guard that runs at least 30 inches past each end of the hatch. Hatches leak at the curb flashing and at worn lid gaskets; a new hatch is a common add-on to a reroof bid.

A plastic dome won't hold a person. OSHA's construction rule treats a skylight as a hole: anyone working near one more than 6 feet above the floor below must be protected by a cover, a guardrail around it or a personal fall arrest system. Covers must hold at least twice the load that could land on them, be fastened so wind or a boot can't shift them, and be color coded or marked "HOLE" or "COVER".

Your own maintenance staff fall under OSHA's general industry rule, which applies the same protection to skylights 4 feet or more above a lower level. Permanent screens bolted over each dome cover both groups. At the roof edge, the construction rule calls for guardrails, safety nets, personal fall arrest or a warning line set at least 6 feet back. Fall protection belongs in the bid's scope, not on an extras list.