Spray Foam for Older Michigan Brick Homes: What’s Behind the Walls in Pre-1960 Builds

If you own a brick home in Grosse Pointe, Ferndale, or Dearborn, you already know the drill: the furnace runs constantly from November through March, the upstairs bedrooms feel like a different climate zone from the living room, and your DTE Energy bill creeps up every winter no matter what you do with the thermostat. You’ve replaced windows. You’ve added attic insulation. And somehow the house still feels cold in a way that new windows and programmable thermostats never quite fix.

The reason is usually behind the walls — and in pre-1960 Michigan brick construction, what’s behind those walls is often nothing at all.

What Pre-1960 Michigan Brick Construction Actually Looks Like

Most brick homes built across Metro Detroit between 1920 and 1960 — the bungalows in Royal Oak, the colonial revivals in Birmingham, the solid two-stories throughout Dearborn and Redford Township — share a common construction method: a brick veneer exterior over a wood-framed wall, with a narrow air cavity separating the two.

In the original construction, that cavity was left empty. Blown-in insulation didn’t become common in Michigan until the late 1950s and 1960s, and even then it wasn’t retrofitted into existing homes until much later. Some homes that were renovated in the 1950s may have a thin layer of fiberglass batt stuffed into part of the wall cavity, but coverage is almost never complete — batts were cut around electrical boxes, stopped short of corners, and compressed against framing in ways that reduce their effective R-value significantly.

The result is a wall assembly that may be R-0 to R-3 at best, sitting in a Zone 5B climate where the International Energy Code recommends R-20 or higher for exterior walls. On a February morning when it’s 10 degrees in Ferndale, that gap matters enormously.

What Can Be Done Without Tearing Out Walls

The good news for homeowners who don’t want to gut their plaster walls is that several retrofit options exist — and two of them work particularly well in Metro Detroit brick homes.

Blown-in injection foam is the most common solution for the wall cavities themselves. A contractor drills a series of small holes through the interior plaster or exterior mortar joints (technique depends on access and the specific wall assembly), injects a two-component foam that expands to fill the cavity, then patches the holes. The foam cures rigid, doesn’t settle over time the way blown cellulose can, and adds meaningful air-sealing in addition to insulation value. For a Grosse Pointe Farms colonial where touching the plaster walls is unthinkable, drilling from the exterior mortar joints and re-pointing afterward keeps the interior completely intact.

Rim joist spray foam addresses a heat loss point that many homeowners have never heard of but every insulation contractor in Grand Rapids and Metro Detroit knows well. The rim joist is the band of framing that sits on top of your foundation wall and closes off the floor framing at the perimeter of your home. In pre-1960 construction it’s typically uninsulated, full of gaps, and in direct contact with cold air from the crawl space or an unconditioned basement. Open-cell or closed-cell spray foam applied directly to the rim joist from inside the basement creates an air and thermal barrier in a location that has an outsized effect on first-floor comfort and energy loss. Consumers Energy has documented rim joist sealing as one of the highest-ROI upgrades available in Michigan homes, and it’s a straightforward one- or two-hour application on most Detroit Metro bungalows.

Basement wall spray foam is the third major lever. If you have an unfinished basement, the exposed concrete or block foundation walls are conducting cold directly into your home’s envelope. Closed-cell spray foam applied to the interior of basement walls adds R-value, acts as a vapor retarder (important in Michigan’s mixed-humid climate), and eliminates the rim-joist cold air loop. In older Birmingham and Royal Oak homes where the basement ceiling height makes it an attractive finishing candidate, spray foam on the walls often pairs with plans to condition and finish the space down the road.

Thinking About Sequencing and Utility Rebates

If you’re working through a list of energy upgrades on a pre-1960 Michigan home, sequencing matters. Air sealing and insulation improvements change the load on your HVAC system — sometimes significantly — so it’s worth understanding those impacts before you replace the furnace. Contractors who do a thorough job will assess your existing ventilation and combustion appliance situation before dense-packing walls or encapsulating a basement, because tightening an older home without confirming there’s adequate fresh air introduces risks that have nothing to do with comfort.

On the rebate side: both DTE Energy and Consumers Energy run insulation rebate programs through their Home Energy Efficiency programs, and the federal Inflation Reduction Act’s 25C tax credit currently covers 30 percent of the cost of air sealing and insulation improvements (up to applicable caps). The programs change annually, so confirm current eligibility directly, but in recent years Michigan homeowners have been able to offset a meaningful portion of injection foam and rim joist work through the combination of utility rebates and the federal credit.

For a 1940s brick colonial in Ferndale or a 1950s ranch in Dearborn Heights, the combination of injection foam in the walls, spray foam at the rim joist, and basement wall coverage typically represents the most complete retrofit possible without disturbing the original plaster, the brick facade, or the character of the home. The house gets tighter, the furnace cycles less, and the disconnect between your thermostat setting and how the rooms actually feel starts to close.

If you’re ready to find out exactly what’s possible in your home, reach out for a free estimate — a qualified contractor can assess the wall assembly, identify the highest-priority areas, and give you a clear picture of what the work involves before any commitment.