Traditionally, concrete has been the predominant material for housing foundation/basement construction.

In Alberta, on average, over 35,000 new homes start construction annually. 75% of them are single-family, semi-detached and townhome units. The total embodied carbon of concrete foundations in these homes is estimated to be 198,410 tCO2e. Replacing concrete with NLT (Nail-Laminated Timber) for building foundations can reduce emissions in three ways.

1) Reduce embodied carbon of the building by eliminating the usage of concrete. A typical 2,200-square-foot single-family home in Edmonton region uses 41 cubic meters of concrete and 530 meters of steel rebars for the basement, resulting in an embodied carbon of these two materials is 12.95 tonnes CO2e. In contrast, constructing the same basement using NLT would result in an embodied carbon of only 1.10 tonne CO2e, less than 10% of using concrete and steel.

2) The NLT basement would use approximately 17 cubic meters of lumber and sheathing, storing and estimated 15 tonne of CO2e in the structure.

3) Cast-in-place concrete requires at least four-days of winter heating in the winter for curing, but NLT foundation does not. By eliminating four days of heating, while NLT foundations do not. This will save 630 liters of propane, reducing GHG emissions by 0.8 tonnes per basement in the winter.

In partnership with the University of Alberta, Landmark plans to construct 60 NLT foundations with various housing types in 2025 and 2026, reducing embodied carbon by 1,103 tonnes CO2e.

Despite wooden foundations, PWFs, have been accepted by Canadian building codes for nearly 40 years, they have not been widely adopted due to general public’s misconceptions about durability of using wood in foundation and concerns that wood is prone to moisture damages as underground structure. These concerns can be addressed through demonstration projects and public education on the features and benefits of mass timber.

This project aims to demonstrate a high-performance mass timber foundation solution using prefabricated Nailed-Laminated (NLT) panels for buildings covered under Part 9 (Housing and Small Buildings) of the Alberta Building Code. Sixty NLT foundations will be constructed for various housing types, starting with simpler walkout townhomes and progressing to more complex single-family homes, to showcase the effectiveness and versatility of the NLT solution.

The goal of the project is to demonstrate a high-performance NLT foundation solution for residential housing and prove its viability. To achieve this, the project has three key objectives:

1) Obtain regulatory in Alberta

2) Construct 60 NLT foundations with different housing types over two years

3) Demonstrate the advantages and economic viability of BLT foundations to support large scale adoption