Renovating a 1910 Character Home with Modern Building Science

Renovating a historic home is about more than preserving its appearance—it’s about combining old-world craftsmanship with modern construction techniques/materials that improve comfort, durability, and energy efficiency.

On this Vancouver project, we lifted a 1910 character home, moved it, and placed it onto a brand-new foundation. Now the focus is on building a basement that performs to today’s high standards while respecting the home’s original structure.

Here’s a closer look at how this unique project is coming together.

Preserving the Original Structure

One of the biggest challenges on this project was retaining the home’s original floor joists while integrating them into a completely new structural system.

The home now sits on a new Quad-Lock Insulated Concrete Form (ICF) foundation, with new LVL floor joists working alongside the original joists.

Combining historic construction with modern engineering requires careful planning and precise execution to ensure the home remains structurally sound while preserving its character.

Building a High-Performance Basement

With the foundation complete, attention turns to preparing the basement floor.

The first step is placing ¾-inch clear crushed rock, which provides a stable, well-draining base beneath the slab. Once installed, the material is compacted to create a solid foundation for the layers above.

Next comes 6 inches of XPS (extruded polystyrene) insulation beneath the slab. This underslab insulation butts into the Quad-lock foundation to remove thermal bridging.

Continuous insulation beneath the concrete helps reduce heat loss to the ground and minimizes thermal bridging, resulting in a warmer, more energy-efficient basement.

Going Beyond Code with a 15-Mil Vapor Barrier

After the insulation is installed, the next layer is a 15-mil polyethylene vapor barrier.

While many homes are built with the minimum code requirement of 6-mil poly, this project uses a membrane that is approximately two and a half times thicker. This provides better impact resistance and soil gas and moisture control.

The vapor barrier is fully sealed, taped, and adhered to the foundation walls to create a continuous layer that helps control ground moisture and protect the finished basement.

Attention to these hidden details contributes to a healthier and more durable home.

Reinforced Concrete for Long-Term Performance

Once the insulation and vapor barrier are complete, a 4-inch reinforced concrete slab will be poured.

The slab is reinforced with 10M reinforcing steel (rebar) to improve structural performance and help resist cracking over time.

When combined with the insulated slab assembly, the finished basement becomes warmer, stronger, and more comfortable throughout the year.

Planning Ahead with Concrete Blockouts

One detail that’s easy to overlook is the use of blockouts in the curb wall.

Before the slab is poured, blockouts are placed where future doorways and curb walls will be located.

By planning these locations in advance, the concrete can be poured as one continuous slab without unnecessary construction joints.

Fewer joints help improve the overall durability of the slab and are especially beneficial in areas where tile flooring will be installed, reducing the likelihood of cracks developing over weak points.

Completing Under-Slab Plumbing Before the Pour

Another critical step happens before the concrete is placed.

All under-slab plumbing must be installed, inspected, and approved before the slab is poured.

Completing this work ahead of time ensures every drain and pipe is properly located while avoiding costly modifications later.

Proper sequencing is essential because once the concrete is in place, making changes becomes significantly more difficult.

Additional Floor Drains for Better Moisture Management

Mechanical rooms often contain equipment that produces condensation, including hot water heaters and heat recovery ventilators (HRVs).

Rather than relying on a single floor drain required by code, this project includes additional floor drains positioned to better manage moisture.

By locating drains near condensation-producing equipment, any water can be safely directed away before it has an opportunity to collect on the floor or the need for pipes to run across the floor to the center drain.

It’s another example of designing beyond the minimum requirements to improve the home’s long-term performance.

Restoring the Past While Building for the Future

Projects like this demonstrate that preserving a historic home doesn’t mean sacrificing modern performance.

By combining a new ICF foundation, continuous under-slab insulation, an upgraded vapor barrier, reinforced concrete, thoughtful plumbing design, and careful construction sequencing, this 1910 character home is being prepared for another century of comfortable living.

At Clay Construction, we believe the best renovations respect a home’s history while incorporating today’s best building practices.

Because great homes deserve both timeless character and modern performance.

— Larry Clay
The Clay Way