Ceiling spray foam insulation in Taber is rarely one surface, because on a stock this age most houses have been added to at least once and every addition brought its own roof, its own ceiling and its own small roof space that does not connect to the original one.
An addition has a ceiling nobody can get to
When a room was built onto the back of a house, its roof was framed to meet the existing one and the space above it was closed in. There is frequently no hatch into it, no way through from the main attic, and no reason anybody has ever looked. That is why the added room is so often the cold one while the rest of the house is fine, and why a survey that only opens the main attic hatch has seen about two thirds of the building.
The join between the old roof and the new one
Where an addition's roof meets the original wall, the old exterior wall is still standing inside the building with a roof on both sides of it. Whatever was on the outside of that wall is now an interior surface, whatever sealed the original eave is now buried, and the detail where the two structures meet was made on site by whoever did the work. On a Taber house that join is the most likely place for the ceiling plane to stop being continuous.
Sealing beats depth on either roof
The mechanism is the same over both parts of the house: warm air leaves through openings in the ceiling rather than passing through the insulation, so a light fitting, a fan, a hatch or the top of an interior wall does more damage than a shortfall in depth. That holds over the original roof and over the addition, and it means the productive scope is a list of openings rather than a number of inches.
What to do when the added roof space cannot be reached
Some of these have no access at all. Where that is the case the honest options are to make an opening, to work from below when the room is being redecorated anyway, or to leave it and spend on the parts of the house that can be reached. All three are legitimate and the third is frequently right. What is not acceptable is quoting the house as though the addition had been assessed when nobody has been in there.
Ceiling Spray Foam Insulation Taber: Common Questions
Why is the added room the cold one? Usually, and usually because its roof space is separate and nobody has ever been in it.
Can you get into it? Sometimes not. Making an opening, working from below, or leaving it are the three honest answers.
How much depth do we need? Sealing the openings first. Depth over a leaking ceiling changes very little either side of the join.
Size the assembly with the R-value calculator, then get a free Taber quote. More on Ceiling Spray Foam Insulation Alberta.