6 min read ·
If you have looked at artificial turf long enough, you have probably seen a bad install. A lawn that sits wet for days after rain. Low spots that puddle. A surface that bounces underfoot because water is trapped underneath. In every case, the problem is the same thing: the drainage was not built properly. In a dry climate this can hide for years. In the Fraser Valley it shows up by the second winter.
What happens under a properly drained turf lawn
Water lands on the turf surface, moves through the permeable backing within seconds, and then needs somewhere to go. That somewhere is a compacted aggregate base, typically 100 to 150 mm of clean crushed stone, graded to a fall so gravity does the work. Water moves horizontally through the aggregate toward the edges or a collection point and drains away. The surface dries fast. You can walk on it the next morning after heavy rain and it feels solid.
On flat lots or in low-lying areas, we sometimes add a perforated pipe through the base connected to a garden drain or soakaway. On sloped Maple Ridge or Mission hillside lots, the grade does most of the work naturally and the base just needs to be built to channel flow in the right direction.
What happens under a poorly drained one
The turf rolls out on a thin, uncompacted base over native clay. Rain soaks through the turf but has nowhere to go because the clay underneath drains at a fraction of the rate the turf lets water through. Water tables under the turf, lifts it slightly, creates a spongy feel. In pet runs this becomes an odour problem quickly. At seams, the freeze-thaw cycle starts lifting edges. Infill migrates into the wet areas. Within two years the lawn looks nothing like it did on install day.
How we build for Fraser Valley conditions specifically
- We excavate 120 to 160 mm depending on the existing soil. On heavy clay we go deeper.
- We compact the sub-base with a plate compactor before adding any aggregate. Skipping this step is the most common shortcut.
- We use clean angular crushed aggregate, not rounded pea gravel. Angular stone locks together and compacts; rounded stone keeps moving.
- We grade the base to a minimum 1.5 percent fall, usually more, so there is always a slope for water to follow.
- On enclosed areas or heavy clay lots we add drainage board or perforated pipe.
Questions to ask any installer
Ask what depth of aggregate base they are putting in. Ask if they compact before adding the aggregate and again after. Ask what fall they are grading to and where the water exits. If you get vague answers, that is useful information. A company that has built drainage-first installs for years can answer those questions in thirty seconds.