What thickness does the job and why

A 3/8 to 1/2 inch drain mat creates a consistent air and water gap beneath the turf so water moves off the surface quickly. That profile is tall enough for high flow yet low enough to keep transitions flush at doors, walks, and curbs.

If your surface is nearly flat and storms hit hard, step up to 1/2 inch and give the water room to move.

Pick the right profile by surface and climate

Concrete, pavers, or tile patios

Use a 3/8 to 1/2 inch dimple or panel style drain mat to deliver fast runoff and avoid trip edges. This balance maintains comfort underfoot and preserves clearances at thresholds.

  • Slope target: 1 to 2 percent is ideal. If slope is under 0.5 percent, favor the higher profile.
  • Transitions: keep finished turf flush with adjoining hardscape to eliminate lips.

Rooftops and balconies

Choose 1/2 inch when runs are long to a scupper or primary drain, or where parapet walls slow discharge. Confirm roof membrane compatibility and follow the waterproofing manufacturer guidance.

Over compacted aggregate bases

You usually do not need a drain mat over a well built permeable base. Build a graded, compacted aggregate system with geotextile separation so water drains through the base and subgrade. Add a drain mat only if you have a localized barrier to flow or a chronic wet spot.

When to go higher profile

  • Frequent heavy rainfall or short intense storms.
  • Very flat surfaces with little or no slope.
  • Long flow paths to a drain or scupper.
  • High pet use areas that benefit from faster rinse through.
  • Freeze thaw regions where added air space helps drying.

Quick sizing checklist

  1. Measure slope. If less than 0.5 percent, plan for 1/2 inch and add auxiliary drainage where possible.
  2. Confirm build height. Add mat thickness plus turf backing and pile at the edge and verify doors clear.
  3. Check the flow path. Make sure water has an open route to drains, scuppers, or the perimeter.
  4. Verify load rating. Select mats that resist crushing under furniture, planters, and foot traffic.
  5. Plan transitions. Use reducers or edge profiles so there is no lip or trip hazard.

Installation basics over hardscape

  1. Clean and dry the surface.
  2. Roll out the drain mat with cups down or channels directed toward the outlet. Tape or interlock seams so water can move between sheets.
  3. Leave a small perimeter gap at walls and curbs to let water reach scuppers or weeps as the design allows.
  4. Lay turf, align grain, and seam with approved tape and adhesive.
  5. Secure edges with perimeter adhesive or mechanical fastening suited to the substrate.
  6. Dress infill and brush the fibers upright.

Spec features to compare

  • Profile height and open area, which control flow capacity.
  • Compressive strength to prevent crushing under use.
  • Integrated geotextile to keep fines out of the channels while allowing water through.
  • UV and chemical resistance for outdoor reliability.
  • Panel size and connection method for faster installation and continuous flow.

Safety and maintenance

  • Keep finished edges flush with walks and thresholds to eliminate trip edges.
  • Clean drains and scuppers seasonally so channels stay clear.
  • After extreme weather, inspect for debris and verify edges and seams remain tight.