A Passive House retrofit method designed specifically for solid-masonry brownstones and attached townhouses — airtight, insulated, and efficient, without putting the brick and brownstone at risk.
Book a Retrofit ConsultationMost Passive House guidance is written for new construction or wood-frame houses. A Brooklyn brownstone is different: solid masonry walls two or three wythes thick, soft stone and lime mortar, floor joists set directly into the brick, ornate interiors, and very often a landmarked facade.
The masonry retrofit takes the Passive House approach — airtightness, insulation, high-performance windows, fresh-air ventilation, and heat pumps — and adapts every step to how a masonry rowhouse actually behaves, especially how it handles moisture.
Before anything is insulated, we look at the condition of the facade, rear wall, parapet, and cellar, and how wet the walls are. Where it's warranted, a moisture (hygrothermal) analysis models how the wall will behave once insulated.
Repointing with compatible lime-based mortar, brownstone repair, parapet and flashing fixes, and gutters and leaders — so bulk water stays out and the wall can dry. Insulating a wet or failing wall is how retrofits go wrong.
On the front facade and other walls that can't be insulated outside, a breathable interior insulation system that lets moisture move and dry, rather than a foam-and-plastic approach that traps it.
Sealing the joist pockets, cornice, and window openings to create a continuous airtight layer, while detailing the embedded joist ends so they stay dry and protected.
Where the street can't see it, there's more freedom: heavy roof insulation and, where permitted, exterior insulation on the rear wall — often the biggest single gains in the house.
High-performance windows suited to the facade, an energy recovery ventilator for filtered fresh air, and right-sized heat pumps to replace the boiler — the rest of the Passive House package.
With neighbors on both sides, a brownstone or attached townhouse shares most of its walls. Only the front, rear, and roof face the weather — which makes Passive House–level performance far more achievable than most owners expect.
A free consultation at the house to see the masonry, the systems, and what's bothering you — drafts, bills, damp, or noise.
A phased scope for your building, with testing, moisture analysis, certified specialists, and Landmarks approvals brought in where needed.
Brownstone Project manages the work start to finish, so you get oversight without becoming your own general contractor.
It's the same goal — airtight, well insulated, fresh air, efficient heating and cooling — adapted for solid-masonry rowhouses. The difference is in the details: moisture-safe interior insulation, protecting joists embedded in the brick, compatible mortar, and working within landmark facade rules.
Not if it's done right. Insulation changes how a masonry wall dries, which is why the method starts with making the masonry sound and uses breathable, vapor-open systems instead of foam and plastic sheeting. Where the risk is higher, a moisture analysis checks the design before it's built.
Yes. Brick rowhouses and attached townhouses share the same solid-masonry construction and party walls, and the same method applies.
Interior insulation adds some thickness to exterior walls, so details on those walls are planned for: kept, carefully removed and reinstalled, or recreated. Party walls are usually left untouched, and the roof and rear wall can often carry most of the insulation.
If your building is in a historic district or individually landmarked, visible exterior work such as windows and facade repairs needs a Landmarks Preservation Commission permit. Interior insulation generally doesn't change the facade. We'll check your address and coordinate any filings.
Yes. Masonry repairs and roof insulation are natural first steps, with walls, windows, ventilation, and heat pumps following. The plan is sequenced so nothing gets undone later.