What's Under Your Lawn? The 5-Layer System That Makes Turf Last 20 Years

Most people see a lawn and think grass. What they don't see is the four layers under it — and that's where most artificial turf installs succeed or fail.

We've been installing turf in the Portland metro and Willamette Valley since 2016, and we've pulled up enough failed installs from other companies to know: when turf goes wrong, it's almost never the grass. It's the base.

Here's what's actually under a properly installed GI Landscape lawn.

Layer 1: The sub-grade

The foundation. We strip the existing lawn, excavate down 5-6 inches, and compact the native soil to 90%+ density. If we skip this, every step you take settles into the ground over the next two years and your lawn starts looking like a topographic map.

Layer 2: Landscape fabric

A woven geotextile barrier that does two things: stops weeds from pushing up through the seams, and keeps the gravel base from mixing back into the soil over time. A cheap install skips this. A cheap install also grows weeds in 18 months.

Layer 3: The drainage core

Four to five inches of 3/4-inch minus crushed gravel. This is the layer that lets rain disappear in minutes instead of pooling on the surface. In Oregon, where we get 40+ inches of rain a year, this is the difference between a yard you can use in February and a swamp you avoid.

Layer 4: The leveling course

One inch of 1/4-inch minus decomposed granite, screeded flat. This is what gives the lawn its perfectly even surface — no lumps under your feet, no rolled ankles when the kids play.

Layer 5: The turf itself

Premium W-blade synthetic grass with a built-in thatch layer. Tuft-bound at over 10 pounds per blade, double-backed with PU coating, and warrantied against UV fade for 12-20 years depending on the SKU you pick.

The result: a lawn that drains faster than real grass, never needs mowing, and looks the same on year 10 as it does on day one.

If you've been quoted a turf install that doesn't break down all five of these layers, ask why. The answer matters.

Related reading

• Real Grass vs Artificial Turf: 10-Year Cost Compared
• 7 Questions to Ask Before Hiring a Turf Installer
• DIY vs Pro Turf Installation: What Actually Goes Wrong

Why GI Landscape: 4.9 stars from 47 Google reviews · Five-year warranty on hardscape · No payment upfront · Licensed, bonded, insured · Canby-based since 2016.