Hey there! I’m Casey Moothart, Carl’s neighbor and now his client. Carl and I share a vision of retrofitting a 100+ year old home to make it as energy efficient as possible. Follow along as Carl and I work to make this 1895 brick home one of greenest homes in Cincinnati.
This renovation will rely on 4 main strategies:
- Airtightness — create an airtight building envelope
- Exterior Insulation — insulate on the outside of the house, thereby
- Use the Thermal Mass of the Brick to my advantage
- Rooftop Solar Panels (7.6 kWh system)
First consider the thermal mass of the existing home. Built in 1895, this house is solid as a rock. It was built completely out of brick using a triple layer of brick in the wall:
The three bricks I’m holding are how the brick wall of this home was laid. Like all homes built at this time no insulation was used interior to the brick. Instead the interior brick surface was plastered and that was it. No insulation at all. This picture shows an area in the kitchen where the plaster has been removed to create an exposed brick interior:
In this area of the kitchen there is nothing but brick between the interior and the exterior. To the right (behind the photo of the Renault Alliance GTA) the brick is covered in a layer of plaster, but again there is no insulation.
Living in a completely uninsulated home is clearly inefficient, but it offers a unique opportunity to put all the thermal mass of the brick to use — an opportunity that we are going to take advantage of during this renovation!
Which brings us to strategy #2 — the plan to insulate exterior to the brick. By applying insulation on the exterior it enables the brick to be heated (or cooled) by the HVAC system to the same temperature as the interior air of the home, and thereby act as a stabilizer of the temperature of the home. Here is a picture of the the northwest corner of the home:
The wall that is white on bottom and gray on top is the north wall of the home. Given the lack of windows on that side can you see how easy it will be to apply insulation over that entire wall? During this renovation we are going to wrap the entire exterior of the home with insulation (polyiso) and then put new siding over that. Future blogs will document this process.
Finally if this house is going to be energy efficient it needs to be airtight. After all, having lots of insulation does no good if cold (or hot) air is continually leaking into the home. A brick wall itself is not airtight at all. In fact during the initial blower door test I could feel a breeze coming straight through the interior exposed brick walls! The solution we decided on was to use a vapor permeable airsealing paint on the exterior of the home. I used Sherwin Williams Sherlastic Elastomeric Pain. In the photo of the north wall above you can see that the lower half of the wall has been painted white — that is the Sherlastic paint. Though I hoped a single coat would do, it turned out two coats were needed to create a continual layer free of any holes.
I painted the entire exterior with this, and the plan is to tape all penetrations and window openings on to the Sherlastic paint, thereby creating an airtight layer all around the home.
So that’s the plan! The fact that this home was built with no insulation at all that, ironically, makes it a great candidate for a deep energy retrofit. Stay tuned for more blog posts as the project commences!