About 81% of homes in Fort Macleod were built before 1991, and the attics in this town are nothing like the open trussed spaces on a modern subdivision. Attic spray foam insulation in Fort Macleod is close work in a shallow roof over a plaster ceiling, and the two things that decide the job are how you get in and whether the roof can breathe at all.
An eave that was never built to let air in
Roof ventilation as a designed pair — intake low, exhaust high — came much later than these houses. A pre-war eave here is often a short overhang with the sheathing boards carried straight out and a fascia nailed on the end. There is no soffit, or there is a solid wooden one with nothing cut into it. Then somebody added roof vents or a ridge vent at the top, which gives exhaust with no intake.
That arrangement does not ventilate the attic. It pulls air out of the house through the ceiling instead, because the house is the only opening available. The attic stays as humid as before and the heating bill goes up.
Three roofs, one deck
Re-shingling is the other thing that has happened repeatedly up here. On a low-pitch roof the usual decision is to lay the new covering over the old, and after two or three rounds the deck is carrying a great deal of weight and holding whatever moisture got in along the way. It also means the roof has not been off in a very long time, so nobody has had a clear look at the deck from above since it was built.
If a re-roof is coming, that is the moment to deal with the attic properly, and it changes the options completely — the work can be done from above, in daylight, without anyone crawling over a plaster ceiling.
The plaster ceiling is the fragile part
Lath and plaster is heavy, brittle, and fixed to the joists with nails that have been there a century. Walking the attic joists of a house like this, with a hose and a suit on, is genuinely careful work. Plaster that is already cracked can let go. So the honest sequence on an old attic is: look first, decide what has to be protected, and plan the access before any equipment comes into the house.
Access itself is often a small trap door in a closet ceiling with no stair. Everything in and out goes through that opening, and on a shallow roof there may be no standing height anywhere in the space.
What is already up there, and whether it stays
Older attics hold all sorts of things. Settled mineral wool, sawdust and shavings, vermiculite, several generations of batt laid in crossing directions, and a layer of dust and soot from the solid-fuel years. Some of that is fine to leave and insulate over. Some of it needs testing before anybody disturbs it, and that is a question to ask before the job is booked rather than on the day.
A knob-and-tube circuit still live in the attic is the other thing we look for, because it cannot be buried in insulation.
Where foam belongs in an old attic
At the ceiling plane as the sealing layer — around the chimney chase, the old flue openings, the stack, the top plates of the partitions, the trap door perimeter — with depth added over the top afterwards if the space allows it.
Where the roof is too shallow to ventilate properly and the eave cannot be opened up, the alternative is to insulate the roof deck itself and make the attic part of the conditioned house. That is a bigger decision and a bigger job, and on a very low-pitch roof it is sometimes the only assembly that actually works. We will say which of the two your roof is suited to, and we quote, schedule and stand behind the work ourselves.
Attic Spray Foam Insulation Fort Macleod: Common Questions
We have roof vents. Isn't the attic ventilated? Only if there is intake at the eaves to match them. Exhaust with no intake draws air out of the house through the ceiling, which is the opposite of what was wanted.
Can you work over a plaster ceiling? Yes, carefully, and the access plan comes first. Old plaster is brittle and the attic joists are the only place to put weight.
Should we insulate the roof instead of the ceiling? Sometimes. On a very shallow roof with no possible eave intake, insulating the deck and bringing the space inside is often the assembly that works.
How much does attic spray foam insulation cost in Fort Macleod? Sprayed sealing work is priced per board foot and blown depth goes on top, so the number follows area and target R-value. On this stock access and removal of old material move it most.
How do I choose an attic spray foam contractor in Fort Macleod? Ask what they intend to do about intake ventilation. Anyone quoting depth on a roof with no eave intake has not looked at the eave.
Size the job with the R-value calculator, then get a free Fort Macleod quote. More on Attic Spray Foam Insulation Alberta province-wide.