Spray Foam Insulation in Drumheller, AB.

76.5% of dwellings are single-detached, so Drumheller is predominantly older freestanding houses, with about 1,196 dwellings built since 1980.

Valley geography compounds the age. Building on and against the coulee walls produces split-level and stepped foundations, partial basements, and additions that meet the original structure at awkward angles — each junction a place where a later air barrier has to be made continuous across two different framing generations. In a flat-lot subdivision the attic is one plane; here it frequently is not.

Drumheller's climate assignment is the weakest in this ledger and should be read that way. It is given RED DEER REGIONAL A (climate ID 3025480) from about 160 km away — 5,619 heating degree days at an 18 °C base, an average January daily minimum of -17.6 °C, -43.8 °C at the extreme. One hundred and sixty kilometres across a change of terrain is a long way to carry a normal.

The town's own published climate table gives a January mean minimum of -18.6 °C, colder than the borrowed figure — but on a 1981–2010 normal rather than the 1991–2020 composite used everywhere else here, so the two cannot be set directly against each other. Both are on record; neither is a 1991–2020 measurement taken at Drumheller.

The Drumheller Institution, a federal prison, is a major local employer. Correctional facilities are continuously occupied and continuously heated across a site of mixed-vintage buildings, so envelope work there is scheduled around operations rather than around the season.