Leaside ICF Addition

This is our first insulated concrete forms (ICF) project; a one storey addition in Leaside. We worked very closely with the homeowner, who designed the addition (Arch Enemy Design, Toronto). It was strongly focused on minimalistic design and simple durable finishes.


The addition was one storey at the rear of the property, with a full basement. The addition gives access to the new basement space, as well as provides a larger dining area. The addition was built using ICF, a strong and highly insulated building method.


  • Toronto-manufactured Amvic ICF blocks used
  • Amvic 3.3 block with 6.5″ of EPS has one of the highest insulation levels of any ICF product – R30
  • High insulation levels inherent to the ICF blocks allowed us to pour the concrete in the middle of winter without providing supplementary heat for proper curing
  • Aluminum baseboards, installed during the drywall phase, wear better than wood and save on installation labour costs of traditional wood trim
  • A 97% recycled drywall was used throughout the home
  • FSC certified NAUF plywood used for window jamb extensions, stair treads, to case walk-through openings and for a custom vanity and cabinet


  • Consultation with a structural engineer confirmed we could use 6” of concrete core instead of 8” to reduce the amount of concrete used
  • Concrete with approximately 40% slag was used to pour the walls. Slag is an industrial by-product which displaces high-embodied-energy portland cement in the mix
  • First floor and roof are framed with engineered wood products: wood I-joists, LVL beams, and oriented strand rim board
  • Engineered wood products use smaller, less desirable wood to create strong, dimensionally stable structural members that can span great distances
  • Exterior metal siding ordered in pre-measured lengths to prevent off-cuts and reduce installation labour
  • Consultation with a building science engineer confirmed a rainscreen would not be necessary as both the siding and exterior of the ICF block are inert to moisture preventing unnecessary use of materials
  • Specialized ICF hardware was used to hang the first floor plate within the ICF walls, eliminating one of the primary air leakage pathways associated with conventional platform framing
  • Salvaged timber used as structural post
  • HRV uses less energy to heat and cool the home
  • Floors in the dining room and basement have polished high-slag concrete with in-floor heating
  • Simple concrete floors prevent the need for additional flooring and provide a low-maintenance, attractive and easy-to-clean surface
  • New front porch uses railings salvaged from the Canadian National Ballet
  • LED lighting throughout addition


  • Organic linseed oil used to finish window jambs, accents and salvaged timber post
  • No VOC primer and paints
  • HRV system improves air quality and reduces energy use


  • Siding was ordered to exact lengths to prevent on-site cutting, reducing waste
  • Construction waste was sorted off-site by the waste hauling service to maximize the amount of waste diverted from landfill


  • Vehicles were used for moving materials and tools when they were required, not for day-to-day commuting
  • Crew members carpooled when feasible