GOING NET ZERO

Deborah: What is Net Zero (for residential projects)?

Carolyn: Everyone is talking about Net Zero. Though definitions may differ, the intent is to reduce greenhouse gas emissions in an effort to address climate change.  For homes, this means a house that is energy efficient, uses renewable energy for power and does not burn fossil fuels - ie no propane, oil or ‘natural’ gas.  

Deborah: What are the main barriers to achieving Net Zero while retrofitting existing homes?

Carolyn: One of the biggest problems is a lack of awareness.  Most homeowners and even allied professionals like realtors, designers and contractors, are not aware of coming regulations.  In Toronto, all existing homes will need to be Net Zero (or close to it) by 2040.  Anyone doing renovations a home today should incorporate Net Zero planning.

Deborah: What are changes or upgrades you think every homeowner should plan for before they renovate?

Carolyn: We all need to go electric.  If you have gas in your home for heating, hot water, cooking etc, it has to go.  Insulation, air sealing, and high performance window and doors will help reduce the amount of money you spend on utilities.  Solar panels can help offset electricity costs and provide more resiliency.  The order that these improvements are completed in needs to be well thought out and sequenced.

Deborah: What do you wish more homeowners knew about Net Zero?

Your home will NEED to be Net Zero.  Understanding what Net Zero means and how to get there is really important. But, rest assured, with a bit of guidance - your home can get there! Also - there are currently government incentives like rebates and loads to help make the transition - take advantage of them while you can!

Deborah: What are you most excited about that's emerging in your field?

Carolyn: So many things! I’ve been working with homeowners to make beautiful and sustainable homes for over 25 years - the pace of change in recent years has been incredible.  I believe there are solutions to the climate crisis that will create an amazing world we can all thrive in.

Learn more about Carolyn Moss and Homes To Zero here.

DECONSTRUCTION

 By Deborah Mesher, Architectural Designer and Rashmi Sirkar, Intern Architect and Sustainability Analyst

Deborah: What is circularity in the construction industry?

Circularity is an approach to designing materials, processes and buildings that subverts the linear "take, make, waste" approach to construction and looks to create a closed loop system. This can be done by re-using existing building materials through careful deconstruction, using more bio-based renewable materials, using construction methods that allow for easier future disassembly, and/or using locally made products and components.

Deborah: What is deconstruction?

Building deconstruction is an alternative to conventional demolition where the building is systematically dismantled in a way that preserves building elements and materials. Residential building deconstruction is often done manually with lo-fi tools. Deconstruction is also evolving to include more advanced machinery and techniques such as panelized deconstruction in which cranes etc. can be used to take apart and transport entire wall panels rather than breaking it up into its constituent parts like studs and sheathing. Deconstruction is an essential process in a system of “urban mining” and building material reuse - but it is not enough to just deconstruct buildings to keep material out of landfill. There needs to be simultaneous development spatial and logistical infrastructure for salvaged material and a market for them too.

Deborah: What alternative materials are available to us? 

If we group products broadly into structure, envelop or interior finishes, there are many bio-based materials that can be used. For structure, low-rise residential construction is already typically wood stick framing, but basements and foundations often use concrete which is incredibly carbon and energy intensive. Locally sourced stone foundations can be a lower carbon alternative to concrete foundations. 

Wood fiber insulation and cellulose insulation too can be used where possible instead of petroleum-based insulation products. Thatch and wood shingles have been used as cladding materials for centuries in vernacular architecture and may still be used with an updated design aesthetic. Hempcrete and strawbale are gaining popularity as alternative materials for exterior walls, though difficult to accomplish on tight urban properties.

Interior finishes can include lime and clay renders, linoleum/cork flooring and mycelium composite flooring. Reclaimed wood can be used for floor, wall and ceiling finishes.

Deborah: What potential does the reuse of wood have? 

Currently salvaged wood is most commonly used as interior finishes - flooring, wall and ceiling panels. There is also a lot of potential for reused wood in outdoor landscaping where boardwalks, seating, planters and trellises can all be made from reclaimed wood. Technically wood can also be reused as structure - most wood studs that have survived 50-60 years within the walls of an old house have the structural integrity to stand within walls of a new house unless they have been damaged by moisture or mold. However currently there are no testing and certification systems which allow for the general reuse of wood as structure. Reclaimed wood can also be used as feedstock for mass timber manufacturing and wood fiber-based insulation. Smaller quantities of salvaged wood can also be repurposed as furniture, and low quality wood can be chipped up for mulch.

Deborah: What can’t salvaged wood be used for? 

As we can see salvaged wood has a pretty wide range of uses since once you plane away the top inch or so the interior layers of the wood can look as good as new. The main process that salvaged wood requires is de-nailing where old and rusted nails need to be removed from it. This can leave various holes in the surface of the piece but will often have little impact on its structural integrity. One of the more common uses for wood waste currently is incineration in waste-to-energy facilities - which can be avoided for higher uses that continue to sequester the biogenic carbon that's locked in the wood.

Deborah: What is emerging in your field that your excited about? 

Many things! Including the role of AI and robotics to de-nail wood and process salvaged lumber that can radically reduce the labour input and cost of this material at scale. Also encouraging is the interest that municipalities are showing in understanding low carbon and circularity that can help create policy and regulation that will enable circular construction at scale.

Learn more about Rashmi’s work here.

INTRO TO CIRCULARITY

by Deborah Mesher, Architectural Designer and Breanne Belitski, Toronto Circularity Network

Deborah: What is circularity in the construction industry?

Breanne: Circularity is about utilizing the Earth's finite resources more intelligently. Circularity challenges us to acknowledge the significant impact of materials of construction that have already been produced—materials that have been mined, quarried, cut, transported, and manufactured, often extensively, before being transported yet again. It is sometimes compared to recycling, but it goes beyond that; it's about minimizing waste from the outset and thinking through the full life cycle of materials.

Deborah: What impact can circularity principles have on design?

Breanne: Circularity should be viewed as an opportunity rather than a constraint. Popular home renovation shows often depict complete overhauls, where everything is discarded and started anew. However, by acknowledging the value of the materials already in use—considering the resources and effort embedded in them—we can shift our design approach. This perspective allows us to think about which elements can be preserved, can we reuse the countertops, refinish the cupboards? And when replacement is required, think about how the wood floorboards can be repurposed to maintain their highest value. Embracing circularity not only fosters creativity but in some instances, also offers financial savings.

Deborah: Why is circularity important? 

Breanne: Circularity is important because our resources are depleting at an alarming rate. Circularity presents a pathway to mitigate some climate related impacts. By demanding fewer resources, reducing our waste, consuming less, and sometimes even building LESS, we can decrease the harm we inflict.

Deborah: What are the barriers to incorporating circularity into residential construction?

Breanne: There are four barriers: societal trends, individuality, knowledge and perceived costs. Social trends, propelled by popular media such as house-flipping shows, DIY Instagram accounts, and HGTV, advocate for a constant cycle of renewal, pushing "out with the old, in with the new". This perspective has become deeply ingrained, encouraging the belief that our homes should be an absolute reflection of individual selves, often leading to us sending items to the landfill, items that still have notable service life left in them.

While the environmental impact of everyday items like plastic bags is well understood, the consequences of home renovation waste are less recognized, leading to a disconnect from the detrimental effects of the linear consumption model. There are not many designers and contractors who know what circularity IS, let alone the practical skills and related support required to apply circularity to a build.

Deborah: What should designers/architects know about circularity?

Breanne: As opposed to the linear model of consumption (the take - use - waste model), the circular model of consumption is designed to be regenerative by design, aiming to retain as much value as possible from resources, products, and materials. The circular model seeks to create a closed-loop system, where waste is minimized, and resources are reused, recycled, or composted, leading to a more sustainable, eco-friendly approach to consumption and production. It challenges not only designers and architects, but also businesses, consumers, and policymakers to rethink how goods are designed, used, and reused, aiming for a balance between economic development and environmental sustainability.

Deborah: What do you wish homeowners knew about circularity? 

Breanne: I wish homeowners knew that their decisions have the power to spur a cultural shift towards more sustainable living practices. By valuing what we already have and considering the lifecycle of our possessions and homes, we can make a profound difference in reducing waste and preserving resources for future generations.

Learn more about Breanne Belitski’s work at the Toronto Circularity Network here.