Fourplex Infill Development, Squamish

2305 Mamquam Road is a standard residential lot in the District of Squamish being developed as a four-unit fourplex under the District’s small-scale multi-unit housing rules. The build quadruples the demand on a site originally serviced for a single-family home, raising two engineering questions for the building permit: whether existing watermain capacity could deliver the fire flows a fourplex requires, and whether grading could absorb the increased stormwater without offsite upgrades.

We provided civil engineering for the building permit, with scope covering site grading, frontage roadworks (a new concrete letdown access), site servicing, an on-site Stormwater Management Plan, Erosion and Sediment Control, and full construction notes. The architectural, mechanical, and landscape drawings were folded into a coordinated baseplan with the existing utility, title, and DP information overlaid.

Fire-flow demand was tested using the simple Fire Underwriters Survey method (FUS 2020 guide) so any need for code-consultant calculations or District watermain modelling surfaced before submission rather than during plan check. Construction-phase services followed, including inspections, BP schedules, DOS form submissions, cost estimates, utility coordination, and record drawings.

The fourplex submission landed at the District as a single coordinated civil package targeting first-pass approval, with fire-flow exposure quantified up front rather than discovered during plan check.