A Net-Zero-Ready Renovation in Calgary
This project required a ton of collaboration with the homeowner and our sub-trades to achieve the full results we needed.
We started out with an original 50's bungalow, which the homeowner wanted to renovate while also making the house much more efficient.
After some initial planning, the goal shifted towards creating a net-zero-ready home - without completely tearing down the existing house.
The homeowners had lived in the house for a while before the remodel and had recently developed their basement into a nice, finished space. Being wary of the cost and of their carbon footprint meant we were to save as much of that space as possible while completely rebuilding the house around it.
After protecting surfaces that would stay in place and carefully removing items that would eventually be reused, along with asbestos remediation, we started by demolishing the interior of the main floor.
We selectively removed the shiplap subfloor to move the stair opening to the centre of the house. At the same time, we tore out all of the non-load-bearing interior walls, electrical, plumbing, and HVAC. One of the biggest challenges of this build was working around the weather to keep the finished basement protected (we started in late winter and continued into Calgary's rainy season).
With the shell of the house still largely intact, we planed down the old 2x10 floor joists to flatten them out and laid new subfloor wherever we could in order to give us a nice clean work surface. Some plumbing and HVAC rough-ins were completed at this stage to keep the project moving along.
At this point, the snow had melted and we turned our focus outside.
We built a large addition on the front of the house using Polycore wall panels. These 12 1/2" thick EPS foam and steel panels are made in Alberta, give us an Effective R-40 wall without adding any extra insulation, and the installation was finished in about one day with two people once the concrete footing was ready.
With all of the prep work done, we luckily hit a good weather window. We carefully demolished the existing main floor (with the exception of one exterior wall), and separated the material into different bins to be recycled.
Dismantling a house by hand is far from efficient, but it allowed us to send the wood and metal waste to the appropriate recyclers, as well as the old asphalt shingles. It also kept the remaining house safe from damage since everything was taken apart piece by piece, rather than full walls crashing down.
Once everything was taken down we removed the rest of the shiplap, added the beams to support the loft/new roof, planed down the existing floor joists and installed new subfloor across the entire main floor.
As with any renovation our progress was heavily dependent on things like site conditions, availability of materials, and weather.
After constantly switching back and forth between demolishing and rebuilding up to this point, we were now ready to focus fully on rebuilding.
Polycore panels also made up the bulk of the main floor walls, and install was a breeze. The panels are shipped ready to install, incorporating all window and door openings, structural components, and electrical service cavities.
The lightness of the panels meant no lifting equipment was needed, even for the taller rake walls.
The roof system was installed in sections, as space constraints onsite meant we couldn't accept the full delivery all at once. Our team did a great job of staggering the build so nothing was left unsupported and forward progress continued.
Once framing was completed, plumbing and HVAC rough-ins were finished - then it was time for insulation.
Insulation was carried out using a variety of methods and products. 6" of GPS (Graphite Polystyrene) foam wrapped all areas of the house that weren't Polycore panels - the existing concrete foundation and some 2x4 walls. Wood stud spaces contain stone wool batts, the vaulted ceiling areas were filled with dense-packed cellulose, and loose-fill cellulose filled the open attic space. The final product leaves us with R-40 walls, and a roof in the R-60 - R-80 range depending on location. These are great numbers, but the care and attention put into proper air sealing will be an even bigger contributor to bringing this house to net-zero.
We used Pro Clima's Intello Plus as our
smart vapour barrier in place of standard 6mil poly, giving us a strong interior envelope to help control moisture year-round. We added a service cavity on top of the Intello Plus for the electrical to run through, which means there are only a handful of wires penetrating through the envelope - and those are all individually sealed.
Innotech triple pane windows complete the envelope of the house - they offer fantastic air sealing and will last a very long time.
On the mechanical side, the house is heated and cooled by a Cold Climate Air Source Heat Pump paired with an HRV unit for circulation, and electric resistive backup for the coldest days. We're also using a heat pump hot water tank, and a ventless heat pump dryer to minimize penetrations.
Because of all of this, we were able to sever the gas line and run the home completely on electricity - meaning the homeowners will not have to pay monthly delivery charges for natural gas they don't use.
The roof was heavily reinforced with double and triple trusses in important areas to support solar panels, and 95% recycled rubber shingles were used to ensure the solar array doesn't outlive the roof.
While this home may not be pursuing official net-zero or net-zero-ready designations, its primary emphasis has been on achieving high-performance standards within budget constraints. The ultimate goal is for the residence to generate all the energy it consumes once the solar array is installed at a later date.
As mentioned, the success of this project is the result of heavy collaboration between our team and the homeowners. Now that drywall is installed, finished and primed, we're handing it off to the homeowners to install flooring, cabinets, tile and all other finishes. They also put lots of time into installing exterior insulation and air barrier, along with the engineered siding.
Obviously we're happy to handle 100% of the scope of any project, but this homeowner's contributions made it possible for this level of performance to fit within their budget.
We're grateful we were able to work on a net-zero-ready renovation like this one, and to have the support of many knowledgable consultants and tradespeople in Calgary - it would be impossible to thank every individual and company that contributed, as it truly was a group effort. We're excited to see how the house performs once it is fully occupied.
We were lucky enough to participate in the Eco-Solar Home Tour this summer while the house was under construction, with the homeowners hosting. Stay tuned as they may be entering their home in the tour next summer as well so everyone can see the finished product!
Fresh Start Projects is a high performance renovator serving Calgary, Alberta.
If you have questions about this project or any other high performance details and products, we're always happy to chat.