Considering Artificial Turf for a Roof Terrace

Assess Your Roof's Structural Capacity

The most critical first step for any roof terrace project, especially one involving additional materials like artificial turf, is to assess the roof's structural capacity. A qualified structural engineer must determine if the existing roof can safely support the added weight of the turf, infill, and any potential pedestrian traffic, furniture, planters, or even accumulated snow or rainwater.

Artificial turf itself is relatively lightweight, but the infill materials (like sand or rubber granules) and the base layers (such as drainage mats or shock pads) can add significant weight. This assessment is non-negotiable and should be completed before purchasing any materials. The engineer will consider the dead load (permanent weight) and live load (variable weight) capacities of your specific roof structure.

Understanding Roof Drainage and Waterproofing

Proper drainage is essential for any roof, and even more so when adding artificial turf. The turf system must not impede the existing roof drainage, which typically involves slopes and drains designed to shed water efficiently. Water accumulation beneath the turf can lead to mildew, odors, and potentially compromise the roof's waterproofing over time.

Consider using a drainage mat or grid system beneath the artificial turf. These products create a void space that allows water to flow freely to the existing roof drains. Ensure your roof's waterproofing membrane is in excellent condition before installation. Any existing leaks or vulnerabilities must be addressed by a roofing professional prior to laying turf.

Selecting the Right Artificial Turf for a Roof

When choosing artificial turf for a roof terrace, consider the specific demands of an elevated environment. High-quality turf designed for durability and UV resistance is crucial, as rooftop spaces often experience more intense sun exposure and temperature fluctuations. Look for turf products that are specifically noted for outdoor, high-traffic applications.

Lumber Plus offers professional artificial turf systems suitable for various applications. For a roof terrace, options such as Wembley, known for its performance and resistance to wear and tear, or Stanford, with its dense, natural appearance and high durability, could be considered. Anfield also offers superb durability and brightness, making it a graceful option for daily enjoyment. Always review the product specifications for UV stability and backing materials.

Pile height can influence both appearance and drainage. A shorter pile height may drain more easily and be less prone to matting, while a longer pile height offers a softer feel. Consider the intended use of the roof terrace – a lounging area might benefit from a softer turf, while a high-traffic path might require a more resilient, shorter pile. You can compare options at our artificial turf product page: "/turf".

Wind Uplift and Securing the Turf

Rooftop environments are often exposed to stronger winds than ground-level installations. This makes securing the artificial turf critical to prevent uplift and displacement. Unlike ground installations where turf can be nailed or stapled into a base, rooftop installations require different methods to avoid penetrating the roof membrane.

Common methods for securing artificial turf on a roof terrace include using heavy infill, adhesive, or a combination of both. Some systems utilize perimeter fastening strips that are adhered to the roof, onto which the turf is then secured. Always consult the turf manufacturer's recommendations for rooftop installation to ensure proper anchorage and to maintain any warranty on the material.

For larger areas, consider the weight of the infill as a primary securing method, ensuring the roof can support it. For smaller, contained areas, a strong, flexible adhesive specifically designed for outdoor use and compatible with both the turf backing and the roof surface may be appropriate.

A Hypothetical Roof Terrace Project Example

Consider a 20-foot by 15-foot flat roof terrace. The client wants to install artificial turf with a drainage mat. The turf selected has a roll width of 15 feet and a pile height of 1.5 inches. The infill will be silica sand, applied at 2 pounds per square foot (PSF).

Step 1: Structural Review. A structural engineer confirms the roof can support an additional 20 PSF, well above the estimated total weight of the turf, drainage mat, and infill (turf: ~0.5 PSF, drainage mat: ~0.25 PSF, infill: 2 PSF = total ~2.75 PSF).

Step 2: Drainage. The existing roof slopes towards a central drain. A 0.5-inch thick drainage mat is chosen, which will be laid directly on the roof membrane. This mat ensures a clear pathway for water to reach the drain.

Step 3: Material Calculation. The terrace is 20 feet by 15 feet (300 square feet). Since the turf comes in 15-foot wide rolls, one 20-foot long roll is needed. This minimizes cuts and seams. The total infill required is 300 sq ft * 2 lbs/sq ft = 600 pounds of silica sand. This will be distributed evenly after the turf is laid.

Step 4: Installation Plan. The drainage mat is unrolled and cut to fit the 20x15 area. The single 15-foot wide, 20-foot long turf roll is then carefully unrolled over the drainage mat. The edges of the turf are secured using a perimeter adhesive applied to the roof edge, ensuring no penetration. Finally, the silica sand infill is spread and brushed into the turf fibers.

This example assumes optimal conditions and a single roll width matching the terrace dimension. Real-world projects may require multiple rolls, seaming, and more complex cutting plans. Always measure your specific area precisely.

Before you order

• Obtain a structural engineering assessment of your roof's load capacity.
• Verify the condition and integrity of your roof's waterproofing membrane.
• Confirm the existing roof drainage system is adequate and will not be impeded.
• Research local building codes and permits required for rooftop installations.
• Select artificial turf specifically designed for outdoor durability and UV resistance.
• Plan for effective drainage beneath the turf, such as using a drainage mat.
• Determine a secure method for anchoring the turf against wind uplift without piercing the roof membrane.
• Factor in the weight of turf, infill, drainage layers, and potential furnishings into the roof's load calculations.
• Consider access to the roof for material delivery and installation.
• Plan for ongoing maintenance, including cleaning and brushing, compatible with a rooftop environment.

Confirm installation details, approved uses and warranty terms in the current instructions for the exact product and profile. Your installer should verify the substrate, structure and applicable project requirements.

Questions to help you decide

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