Why Northframe uses mass timber infill

Northframe Block C is a concrete tower with mass-timber infill between the cores. The earlier building on the same block was all-concrete; this one uses mass timber for the floor plates.

The reason is twofold. The timber lowers the embodied carbon of the floor plates by roughly a third. It also changes the interior: exposed timber ceilings warm the rooms acoustically and visually, and the timber holds humidity steadier than concrete alone.

The trade-off is fire code. The timber is over-provisioned by 40 mm so that even in a design fire, the char layer leaves enough structural section. That over-provision is the cost of being allowed to expose it.

Residents will see the difference most clearly in winter, when the air inside stays between 35% and 45% relative humidity without humidification.