Versatility showcased in multi-application residential install

The Harvey Home is a 2,400-square-foot custom home by builder Jeff Harvey of Harvey Homes & Interiors. Located in Gravenhurst, ON, the residential home is situated on the Canadian Shield, built on a sloping lot comprised in large part of solid bedrock and surrounded by dense forest. The lot required extensive blasting to level and prepare the site for the home’s slab-on-grade foundation. The single-story, ranch-style home features 3 bedrooms, a two-car garage, cathedral ceiling and plenty of natural light.

The Goals: Comfort, efficiency, safety & sustainability

Jeff Harvey of Harvey Homes and & Interiors worked closely with the homeowner, Mike Harvey and his wife Lorraine, on the design and build process. The consultation process determined the key goals of the build. Intended as the couple’s forever home, it was important to create a dwelling that was both comfortable and energy efficient, especially since the family’s previous home was often drafty and cold with a furnace that rarely cycled off during the heating season. Sweaters and throws were previously a staple for the couple. As such, the home’s comfort factor was considered top to bottom, literally. “Ever notice how once your feet are cold, the cold just moves right through you?” noted the homeowners. “Thermal comfort is just one of those things—you might not notice if you have it, but you sure do notice if it’s missing!” Also among the overall objectives was the desire to save on heating and cooling costs, achieving a home that’s high on comfort but low on its carbon footprint—efficient, sustainable and economical. As a retired firefighter, safety was top of mind for homeowner Mike, who wanted fire protection built directly into the home, given its location in the heart of the Muskoka Region—a heavily forested area in prime Ontario cottage country that is at heightened risk for wildfires. Surrounded by nature, the couple also wanted to be environmentally conscious, opting for green building materials in the construction of the home while also aiming for long-term durability.

The Challenge

The first challenge in the home’s design and construction was the environment. The lot was largely comprised of a deep, unforgiving bedrock, which had to be blasted to achieve more level ground before building activity could begin. Blasting took place over several days with tons of rock removed or relocated on site. Even with extensive leveling to prep for the home’s monolithic concrete slab foundation, the builder sought an underslab insulation product that could conform to any ground irregularities, that could offer excellent material handling, and that could stand up to heavy foot traffic.

Harvey Homes and & Interiors also considered the climate zone and the seasonal temperature extremes that are common to the Muskoka region. In order to achieve a durable home, the building envelope would need to be constructed to withstand extreme heat and cold, humidity and precipitation, as well as seasonal changes in vapor drive for effective moisture management. The area typically experiences summers where temperatures can reach the mid-thirties (95°F), while winters can see temperatures that drop to -30°C (-22°F) with heavy snow, so a tight building envelope for efficiency was a must.

Resilience, in terms of fire safety, was considered a vital part of the build with the build plan incorporating best practices for WUI zone construction in order to mitigate fire risk.

While Muskoka is known for its tranquility, outdoor to indoor sound transmission was top of mind, given the home’s proximity to the Muskoka airport as well as common noise-generating outdoor tasks and activities such as tree cutting and maintenance, log splitting for firewood, atv’ing, snowmobiling, etc. With a single-level home design, the homeowners also sought solutions for room-to-room sound dampening, so that activity in the main open-concept living area would not carry through to the bedrooms.

One non-negotiable was the home’s aesthetic. The homeowners selected a traditional blue Hardie® wood siding, so all components needed to be compatible with the desired cladding material. Style definitely had to meet function on this build, which presented numerous building envelope considerations.

The Solutions

To insulate the monolithic concrete slab foundation, Harvey Homes & Interiors opted for ROCKWOOL Comfortboard® 110 in a 2.5-inch thickness to achieve an R-value of R10, exceeding the code requirement of R6. The boards were installed, end to end beneath the slab and around the slab perimeter, with staggered, tight-fitting seams. The exception was under the load-bearing footings where extruded polystyrene (XPS) was used.

“Wherever we could, we opted for and much preferred the stone wool boards,” noted Jeff Harvey.” You could notice a significant difference in how forgiving and comformingconforming they were to variations in the ground, and they were much more durable to foot traffic. While the foam boards were susceptible to shifting and gapping—and even cracking if you accidentally stepped the wrong way—the ROCKWOOL Comfortboard® seemed to grip the ground and never moved. The dimensional stability made handling easy, and there was never a worry about movement or damage during install, during the slab pour or when backfilling. The seams stayed tight and, best of all, it was dream to cut to achieve angles and custom fit around penetrations.”


The Harvey Home

Gravenhurst, Ontario

The Underslab assembly (bottom to top):

  • dirt/earth
  • gravel substrate
  • X” XPS foam boards under load-bearing footing
  • 2.5” Comfortboard® 110 under poured concrete slab and above crushed stone
  • 2.5” Comfortboard®110 between slab edge and foundation wall, (acting as a thermal break)
  • 15 ml polyethelene radon/vapour barrier
  • Rebar
  • Radiant heating pipes
  • Poured concrete slab

Design Considerations:

Climate Zone: 6, bordering on climate zone 7A

Drainage/Condensation/Moisture – stone wool offered high vapor permeability and low moisture sorption

Compressive and tensile strength – 584 psf (28 kPa) @ 10 % compression – 1,566 psf (75 kPa) @ 25 % compression

As a builder, if you can choose superior materials that improve the quality, durability and resilience of the building, while making safer, more comfortable and more sustainable, why wouldn’t you do that? I feel like we owe it to our customers and our communities to treat all builds like they are for family.

Jeff Harvey

Harvey Homes & Interiors

Project Data

Year 2021 - 2022
Southern Ontario
Building Type Slab-on-grade residential home
2,400 sq. ft.
ROCKWOOL Product & Application ROCKWOOL Comfortboard® 110 – Continuous exterior
ROCKWOOL Comfortboard® 80
ROCKWOOL Comfortbatt® – Exterior Cavity Walls
ROCKWOOL Safe’n’Sound® – Interior Walls