About 62% of homes in Redcliff were built before 1991, which puts most of the town's roofs in the era before anyone drew an air barrier on a house plan. Attic spray foam insulation in Redcliff is therefore retrofit work almost everywhere, and on the original townsite stock there is a structural quirk that decides how the job is done: the attic is frequently not one space.
A storey-and-a-half roof is three separate problems
A good share of Redcliff's older houses are one-and-a-half storeys, with a short upstairs tucked into the roof. That shape produces a flat ceiling over the upper room, a sloped section following the rafters, and a triangular void behind a low knee wall on each side, usually with floorboards over it and boxes stacked on top. Those are three different assemblies with three different access conditions, and a crew that only insulates the part it can stand up in has done a third of the house. The knee wall is the one that gets missed. It is a vertical wall with an unheated void behind it, often with nothing in it at all, and it sits directly beside the bed.
Why the sloped section is where foam earns its place
In the slope there is no room to add depth. The rafter is shallow, the finished ceiling is fixed to it, and whatever cavity exists has to deliver both the insulation and the ventilation path or none at all. Closed-cell is the only product that gives useful performance in that thickness, at roughly R-6 to R-7 per inch, and because it becomes a vapour barrier at around two inches it also stops the warm indoor air that would otherwise be driven up through the slope into the void above. Blown-in material cannot be made to stay in a slope, and nobody should be charged for trying.
The knee wall void is an attic with a wall in front of it
Treat it as one. The floor of that void is an insulated ceiling over the room below, the wall is an exterior wall of the room beside it, and the two meet at a corner that needs to be continuous. We spray the back of the knee wall and carry the foam across the joist ends at the floor so that the corner closes. Without that, air moves out of the room, along under the floorboards and up into the roof, and the owner reports the upstairs being cold no matter how much insulation went in overhead.
What the rest of the ceiling plane needs
Over the flat sections the usual list applies and is worth doing properly in a house of this age: the plumbing stack, the bathroom fan, any old chimney chase from the days of a different heating system, and the top plates of interior walls. We seal those with foam and then bring the open flat up to depth with blown-in on top, which is the sensible division of labour between the two materials.
Attic Spray Foam Insulation Redcliff: Common Questions
Why is our upstairs cold when the attic was done? Because on a storey-and-a-half house the attic that was done is usually only the flat part. The slopes and the knee wall voids are separate work and they are closer to the room.
Can you blow more insulation into the slope? No, and it would not stay there. The slope is closed-cell work or it is nothing.
Do the knee wall voids need to be emptied first? Yes, the floorboards over them have to come up to reach the joist ends. That is scope, and we say so before the job rather than during it.
How much does attic spray foam insulation cost in Redcliff? On this stock the number follows how many of the three areas are in scope, because the flat is cheap per square foot and the slopes and knee walls are not. Priced per board foot of sprayed area plus blown-in depth over the flat, so access drives it more than roof size does.
How do I choose an attic spray foam contractor in Redcliff? Ask them to describe the attic they walked. On an older Redcliff house the answer should mention the slopes and the voids behind the knee walls, not just a square footage.
Size the job with the R-value calculator, then get a free Redcliff quote. More on Attic Spray Foam Insulation Alberta province-wide.