A good number of the original Devon houses were built as a storey and a half, with bedrooms tucked up under the roof. That shape produces the hardest ceiling in residential construction, and ceiling spray foam insulation in Devon more often than not means dealing with it. From inside an upstairs bedroom it reads as one continuous surface. Structurally it is three different assemblies meeting at two awkward joints, and each of the three fails in its own way.
Three assemblies, not one ceiling
Low down there is the knee wall — a short vertical wall standing on the upstairs floor, with unheated triangular attic space behind it. Above that the ceiling follows the slope of the roof, with nothing between the finish and the sheathing but the depth of a rafter. And at the top there is a small flat ceiling with a conventional attic over it.
The flat part is the only one anybody can easily insulate, which is why it is usually the only one that was.
The sloped section has no depth to give
A rafter in a house of this age is shallow, and the sloped ceiling needs the same rafter to carry insulation and a ventilation path to the ridge. Fill the bay with fibre and the vent path is gone; leave the vent path and there is almost no room for insulation. This is the single assembly in a house where closed-cell foam's R-6 to R-7 per inch is not a marketing point but the reason the job is possible at all — it buys usable performance in a bay that cannot physically hold enough of anything else.
The knee wall is the leak nobody looks at
Behind that short wall is a cold triangular void, and the floor of it is the open joist cavity running under the upstairs bedroom floor. Warm air from the room below rises into those joist bays, travels sideways under the floor, and vents into the triangular space behind the knee wall — bypassing every bit of insulation in the house. Sealing the knee wall face and blocking the joist bays where they pass under it is frequently the largest single improvement available in one of these houses.
Flat ceilings in the later subdivisions
Devon did not stop building in the 1950s, and the newer subdivisions on the edges of town have ordinary trussed flat ceilings with modern depth already in place. There the ceiling job is not depth at all. It is the penetrations: the plumbing stack, the fan housings, pot lights, and the top plates of interior walls. Insulation slows heat; it does not stop air, and air carries most of the loss through a ceiling that already has depth.
What to tell us when you call
Which room is cold, and whether its ceiling is flat or sloped. On a storey and a half those two answers point at completely different work, and knowing in advance changes who comes and what they bring.
Who does the work
Ceiling spray foam insulation Devon gets handled by us from the walk-through onward. We quote and manage it, and our own installers apply the foam.
Ceiling Spray Foam Insulation Devon: Common Questions
Upstairs is freezing in winter and roasting in summer. Why? Because the sloped part of that ceiling has almost no insulation in it and the knee wall behind your furniture opens onto a cold void. The flat bit at the top is usually fine.
Can the sloped ceiling be done without opening it up? Rarely well. To spray the rafter bay the finish has to come off, and that is why this work usually happens alongside a bedroom renovation.
What is a knee wall and why does it matter? The short wall where the sloped ceiling meets the floor. Behind it is unheated space, and the floor joists run straight into it, carrying warm air out of the room below.
How much does ceiling spray foam insulation cost in Devon? Priced per board foot of sprayed area, so a sloped ceiling costs by rafter area and target thickness. Whether the finish is already off is the biggest variable on a storey-and-a-half house.
How do I choose a ceiling spray foam contractor in Devon? Ask them to describe the three assemblies in your upstairs ceiling before they price it. Anyone treating it as one flat ceiling has not looked.
Size the assembly with the R-value calculator, then get a free Devon quote. More on Ceiling Spray Foam Insulation Alberta.