Is my House Solid brick?
by Keith Tripp, 2020
Toronto has a longstanding love affair with brick. Especially after the great fire of Toronto 1849, brick has been the building material of choice. Bricks were made right here in the City at multiple locations on the East side and even in Mississauga! “Solid brick” is the term used for double wythe brick, or two layers of masonry providing the wall structure. Older houses (pre-1940s roughly) may even be more than two layers thick. The double wythe brick can be identified by the short ends of the brick. See in the photos, every sixth row has short ends of brick showing. These are the bricks that are tying the two layers together. Looking at the wall from the inside of the garage shows the bricks tying the wythes together, and the plain block ( about 4 inch) used as the inner wythe.
There are pros and cons of solid brick construction, when comparing to the more recent and common wood frame-brick veneer construction.
Con A) Because there is no wood frame on the interior, there is basically no insulation in the walls of a solid brick house. Behind the drywall or plaster/gypsum board interior finish, there may be a vapour barrier material, but typically the interior boards are installed on thin ¾ inch nailing strips that are attached directly to the brick wall. The thick brick wall provides thermal mass, which delays heat transfer, but almost no insulation value. The air gap behind the drywall, and the air films on the surfaces provide the only insulation value.
Con B) The floor joists are embedded in the brick wall. If the first floor is at ground level and subjected to exterior water, there is risk of moisture damage to the end of the joists where they are set into the wall. This won’t be visible from the interior or exterior.
Con C) Renovations are difficult at exterior walls because there is no wood frame to route electrical or plumbing through. Penetrations through the header area, such as to pass vent pipes for HVAC equipment through, require drilling through the two layers of brick. Penetrating the walls, such as to install a kitchen exhaust opening, also requires drilling through the two layers of brick.
Pro a) It is likely that a second storey can be added on to a solid brick bungalow or split-level house. This would have to approved by a qualified structural engineer, however based on what I see occurring in my neighbourhood, the double wythe walls are capable of supporting more wood frame structure additions.