Insulated garage doors in Ottawa: reading the R-value, the layers and the core

What the R-value on the brochure measures

DASMA, the door makers’ association, describes the usual published R-value as a calculation through the centre of one door section. Joints between sections, hinges, hardware and the perimeter are left out of that figure.

The U-factor is tested. A whole door is installed in an independent lab under ANSI/DASMA 105, one face warm and one cold, and the heat moving through is measured. Lower is better: 0.20 is twice as efficient as 0.40. DASMA says the two methods are completely different, so a U-factor cannot be read off an R-value as its inverse. It defines a thermally efficient door as one with an insulated core and a thermal break, a non-metal strip in the meeting rail that interrupts the path between outside and inside steel.

When two quotes show R-16 and R-12, ask each company how its number was produced. A calculated figure from one brand against a tested figure from another tells you little.

One layer, two layers, three layers

• One layer. A single sheet of molded steel, usually 2 inches deep for stiffness. Suits an unheated, parking-only garage.
• Two layers. Steel outside with a foam panel behind it, covered by rigid styrene to keep the foam from catching fire.
• Three layers. Steel on both faces, insulation between. One Canadian maker lists polystyrene versions at 1⅜, 1¾ or 2 inches and polyurethane mostly at 1⅝ or 1¾ inches.

Insulated doors are heavier, HomeStars notes, and that weight reaches the springs and the opener.

Polystyrene or polyurethane

Polystyrene is expanded foam cut to size. Polyurethane is mixed, swells to fill the section and sticks to the steel. The same maker puts polyurethane at about twice the insulating value of polystyrene inch for inch, with a stiffer section against wind.

HomeStars’ replacement guide gives polystyrene about R-6 to R-9 at $300 to $600 over a single-layer door, and polyurethane about R-12 to R-18 at $600 to $1,200, stiffer and quieter in operation. Its installation guide gives $200 to $600 for adding insulation, so quotes vary by model and size. Full door prices are on new garage door.

Matching the core to the garage

HomeStars matches the core to use: non-insulated or polystyrene for a detached parking garage, R-12 or more for an attached one, polyurethane at R-12 to R-18 with a full perimeter seal for a workshop, a thick polyurethane core with windowless sections for a music room.

The door is one side of the box. A high-R door on bare stud walls only gets you part of the way, the installation guide says, and HomeStars’ Ottawa page points to an insulation company for the walls and ceiling. Drafts at the bottom or the seams come from a single-layer door or worn seals, so put the weather seals on the same quote.

A bedroom or office over the garage

HomeStars lists a hard-to-heat room above the garage as a reason to move to polyurethane at R-12 or more. The floor of that room is a separate assembly. The City of Markham’s builder tip on the 2024 Ontario Building Code says a floor above a garage must be insulated, with an air barrier and a vapour barrier, and that spray foam under the floor has cut cold-floor complaints there. In your request, say whether the room above is cold and whether the garage is heated. The door company prices the door; floor and ceiling go to another trade.

Weight, springs and the opener

New doors normally come with matched tracks, rollers and springs; reusing old springs or tracks wears the door and the opener. An opener under about ten years old, powerful enough for the new weight, can often be remounted and recalibrated. An older half-horsepower unit may strain under a thick polyurethane double, and openers made before 1993 lack the photo-eye sensors now required. More on the garage door opener page.

What the quote should name

• Model, size, layer count, core type and thickness
• The R-value, how it was produced, and any U-factor
• Thermal break, window glass and window area
• Springs sized to the door, tracks, rollers, seals
• The opener kept or replaced, and removal of the old door

Ontario requires a written agreement for home renovation work over $50, recommends a deposit of 10% or less, and allows 10 days to cancel a contract signed at home.

Who you are dealing with

Ottawa Garage Door Desk passes your request to one independent local garage door company. That company calls you back, measures the opening, quotes the insulated door and installs it under its own contract with you.