Spray foam roofing in Strathmore covers low-slope roofs on commercial and service buildings, and on an open site the thing that governs the specification is not the cold, it is what the wind does at the edges of a large flat surface.
The corners and the perimeter, which is where wind works
On an exposed site the pressure across a wide low roof is not uniform. It is highest at the corners and along the perimeter, which is exactly where a covering is fixed down and where any covering fails first. That is the argument for a sprayed and adhered roof on this ground rather than a mechanically attached membrane: the surface is adhered continuously to the deck rather than held at points, so there is nothing for the wind to get under and no fastener pattern to work loose over twenty years.
What a bare roof does with the snow it is given
Snow does not sit evenly on a roof out here. It scours off the open field of the surface and drifts against every upstand: the parapet, a rooftop unit, a stair enclosure, the change in height where one part of the building is taller. Those drifts are where the meltwater ends up and where the load concentrates, and they are the places a survey looks at first. It is also why drainage on a wide Strathmore roof needs checking against where the snow actually goes rather than against where the drains were drawn.
Rooftop units on a service building, and what they do to a roof
Buildings of this kind accumulate equipment: exhaust for a bay, make-up air, a compressor, a unit added when a tenant changed. Each is a penetration through a roof that used to be continuous, each was installed by a different trade at a different time, and on an exposed roof each one is also an obstruction that snow banks against. On the buildings here the penetrations are almost always where a survey finds the problem rather than the field of the roof.
What twenty years of working fasteners leaves behind
On a mechanically attached roof every fastener is a small hole through the membrane held closed by a plate and a washer, and on an exposed roof each of those has spent two decades being worked as the surface lifts and settles in the wind. The failures that follow are not dramatic. They are a slow enlargement of the hole, a plate that has cut into the sheet, and eventually water tracking down a fastener into the deck below with no visible sign on the surface. That is why a survey on a roof of this age on this ground pays particular attention to the fastener pattern rather than to the seams, and it is the condition that most often decides whether a recover is still available.
Spray Foam Roofing Strathmore: Common Questions
Why not a mechanically fixed membrane? On an exposed roof the fixings are the weak point. An adhered surface has nothing to get under.
Where does it usually go wrong? At the penetrations and wherever snow banks against an upstand. Rarely the middle of the roof.
Can you work while we are open? Yes, and on a building with customers travelling in that generally matters more than the cost.
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