A number of factors could be to blame for the neighbourhood’s appearance – from shifting and settling to poor construction and nearby drilling – but in Vancouver peat is the likely culprit.
What the Peat?
Peat is a soil-like material consisting of partly decomposed vegetable matter that is high in moisture, causing it to be easily compressed and less able to sustain weight.
Vancouver has 11 major peat bog areas and anyone buying or building a home in the city should be aware of them for one reason: peat comes with added challenges.
Digging for Solutions
According to Jeff Langford, co-owner of JDL Homes Vancouver, homeowners have two options when building on peat.
“The first option is to excavate the site and remove the peat completely down to a bearing substrate and then backfill with an engineered product that can bear the weight of a home,” Langford said.
He added that excavation is the best solution when the peat is relatively thin, but for homes on thicker peat, a screw pile is needed.
“It’s a large metal drill, or screw, that is driven into the ground until it reaches a bearing material that can carry the weight of the home,” he said.
In new home construction, there are typically 2 different types of piles used. The most commonly used is the helical pile. The helical pile is a giant screw and is driven into the ground until it reaches hard pan, the layer underground that is stable enough to support the weight of the home. A friction pile is most often used in bridge or high rise construction. The friction pile is driven into the ground similar to the helical pile, however the depth is determined by the engineer. These piles work collaboratively when wind or other forces push and pull a bridge or high-rise, the friction underground keeps the structure stable.
The pile was first developed in British Columbia to help construct commercial properties in peat-rich Delta, where Burns Bog occupies a quarter of the district municipality and a total of 3,000 hectares.
The commercial screw pile was later modified to help homeowners struggling with peat on their lots, according to Langford.
While this option might sound complicated, it is fairly routine for the right builder.
“It’s just another step in the home construction process,” Langford said. “It doesn’t add a tremendous amount of complication to the overall build.”
In its 10-year history, JDL has built and renovated many houses on peat land using both techniques.
Don’t let peat compromise the structural integrity of your home. Call JDL today. Our expert homebuilders can advise you on what to do when renovating or building on peat.