Frequently Asked Questions

LiveRoof systems are compatible with nearly all waterproofing types: EPDM, TPO, PVC, bituminous, polyurethane, rubberized asphalt, inverted or conventional. We work with all appropriate waterproofing products from all manufacturers. In every case, the manufacturer's approved LiveRoof-compatible build-up should be specified and followed.

Yes, pavers may need cutting at perimeters or around penetrations and equipment. For the cleanest cuts, LiveRoof recommends a wet saw with a 14" diamond concrete blade. Place a piece of tape over the cut line to prevent chipping. Most chop saws or circular saws require cuts on both sides of the paver. Curved cuts are made by making several angled straight cuts, and notches can be cut using an angle grinder with appropriate plastic-cutting blades.

Spray rotor systems are the least expensive to install, easiest to maintain, and apply water most efficiently. Vegetated Roof soils are predominantly composed of inorganic aggregates with poor capillary qualities — drip irrigation requires prohibitively close tube spacing, and sub-irrigation risks root rotting and uses more water. A well-designed overhead spray irrigation system provides even coverage to the surface of plants and soil at a very low installation cost.

Retention means a specific volume of water is held on the roof indefinitely. Detention means temporarily delaying stormwater before discharging it as runoff. RoofBlue DETAIN delays and controls stormwater flow to prevent system overflows. RoofBlue RETAIN captures and holds stormwater, transferring water upward toward plant roots as soil dries — maintaining moisture for plant health and reducing irrigation needs.

A blue roof is designed to slow or store stormwater runoff, easing the burden on stormwater systems. When combined with the LiveRoof vegetated roof system — which is itself an effective stormwater tool — the RoofBlue system maximizes rooftop stormwater management capability. This may greatly reduce or eliminate the need for cisterns, detention ponds, or underground storage tanks.

Control flow drains are designed to slow the rate of runoff from roofs during storm events. They typically have an insert with a weir that regulates water flow and are available in a variety of heights. Flat roofs typically use lower weir heights than sloped roofs, and some models have adjustable weirs or copper flanges to inhibit root growth. A licensed professional engineer should carefully design all control flow drain systems. Common manufacturers include Raintrol by JR Smith, Zurn, Flo-Set by Josam, Thaler Metal, Accuflow by Mifab, Flash-Tite by Lexcor, and WADE.

Most membrane manufacturers have special requirements for blue roof applications. In the early stages of blue roof design, it is critical for engineers and specifiers to work with membrane manufacturers to select appropriate materials, thicknesses, and assembly instructions according to local code. Also confirm specifications comply with your municipality's requirements, as some jurisdictions have specific blue roof regulations.

RoofBlue DETAIN applications should hold no more than 3.5 inches of water beneath the vegetated roof system. Each inch of water weighs approximately 5.2 lbs/sq ft, so at maximum detention the blue roof solution adds up to 18.2 lbs/sq ft to the weight of the vegetated roof modules. Maximum saturated weights for RoofBlue RETAIN by module type: Lite ≤29.5 lbs/ft², Standard ≤41.5 lbs/ft², Deep ≤62.5 lbs/ft², Maxx ≤77.5 lbs/ft².

The need for supplemental irrigation depends on plants selected, local climate, weather patterns, roof slope, and system type. In the north temperate zone, irrigation may seldom be required, but a backup system is recommended for prolonged hot, dry, windy, sunny weather. Irrigating even once per month during protracted dry weather can keep your vegetated roof looking its best. In predictably hot and dry regions, always incorporate irrigation into the design.

RoofStone follows roof contours and can create walkways, patios, and landing areas. It can also be used on roofs that must be ADA-compliant with slopes up to 1:48 (2.08%, or ¼ inch per 1 foot), which is the standard minimum roof slope for drainage.

In our experience, most roofing assemblies recommend that water does not stand for longer than 24 hours. However, architects and engineers should confirm the maximum detention time allowable with the membrane manufacturer before specifying drain types, sizes, and placement.

The LiveRoof system weighs approximately 27–29 lbs/sq ft (with a media depth of 4") when fully vegetated and saturated. The soil follows FLL standards with enhanced sustainable organic content, intentionally avoiding excessive organics that shrink from decomposition or perlite that breaks down during freeze-thaw cycles.

Retrofitting depends on structural weight-bearing capacity. A qualified structural engineer must always be consulted before installation. The LiveRoof Lite system was developed for existing buildings, featuring 2.5" of soil with saturated weight of 15–17 lbs/sq ft, expanding vegetated roof opportunities on older structures.

LiveRoof is most commonly used on well-drained, low and mid-slope roofs atop industrial, commercial, institutional, governmental, and residential buildings that can support vegetated roof weight. Vegetated Roofs must only be installed on appropriately engineered buildings.

Yes, LiveRoof modules can instantly landscape median strips, patios, plazas, and malls with fully mature ground covers.

Yes, typically on rooftop patios where load limits prevent substantial soil volumes. Fill planters with closed-cell foam except the top 4.5–6.5 inches, then set LiveRoof modules on top for visual soil depth appearance.

LiveRoof's project showcase features volunteered projects from across North America. Submit high resolution photos to sales@liveroof.com or reach LiveRoof Global headquarters via our Contact page, and your project may be featured in the next design guide printing.

Contact your LiveRoof local grower or reach LiveRoof Global headquarters via our Contact page, or email sales@LiveRoof.com. For Ontario and Atlantic Canada, contact Kees Govers via our Contact page or email kees@liveroofontario.ca.

Landscape and roofing contractors interested in offering LiveRoof installation services should contact their local representative. LiveRoof has developed an online training program for contractors on their first project covering product, installation, and maintenance specifications. Before the first project installation, LiveRoof representatives conduct in-person training with the job site foreman and installation team.

Yes, LiveRoof modules can be cut to size and shape using a masonry saw or reciprocating saw. When custom cutting LiveRoof modules, the cut side should abut the non-cut side of another module, in order to contain the soil and minimize the work of installation. The cut side should not abut edging on the low, draining side of the roof.

The life cycle of most weeds is about four weeks. Therefore, by weeding every 2 weeks, for just a few minutes, the few weeds that come from birds and the wind are not allowed to reproduce. Lean, preventative maintenance is far more effective and economical than reactive maintenance.

Measure your system's output using rain gauges or tuna cans placed in a line from the sprinkler. Run sprinklers for 15 minutes, measure water depth, then calculate the duration needed for your target depth (typically one inch). Adjust based on your vegetated roof's specific needs.

Minimal, sparse walking is acceptable — one person a couple times weekly. Avoid creating single paths, standing in one place, or trampling plants. Wait until foliage is dry before servicing equipment, and cover plants with plywood or foam for up to four hours. Avoid foot traffic when plants are wet or frozen.

Yes, but likely not annually. Send soil samples to a lab qualified for vegetated roof soils each spring before growth begins. If nitrogen levels are low, apply controlled-release fertilizer. Application rates typically range from 1.5 to 3.0 pounds of actual nitrogen per 1,000 square feet.

No, LiveRoof plants are damaged by de-icing chemicals. Use sand or cat litter instead for anti-slip measures after shoveling.

Yes. Use a flat-bladed shovel to locate container edges, peel away plant material, then use pliers to lift modules. Replace modules when finished. Never use sharp instruments around roof membranes.

Dog urine and excrement kill succulent plants. Vegetated Roofs specifically developed for dog traffic use turf grass or lily-turf species like Liriope, requiring minimum six inches of soil. Pick up excrement and water regularly to flush urine from soil.

In the Lite and Standard systems, we recommend plants with extreme drought resistance — succulent, water-holding plants like Sedums, Alliums, Sempervivums, and Delospermas. The best LiveRoof plants employ Crassulacean Acid Metabolism (CAM), making them up to ten times more efficient with water conservation than non-CAM plants. In the Deep and Maxx systems with irrigation, a broader plant palette is possible. Consult your local LiveRoof representative for climate-specific recommendations.

Yes. Numerous vegetables, herbs, and select fruits (such as strawberries and melons) may be grown on intensive vegetated roofs that receive frequent watering, have ample sunlight, and have proper soil. Edible plants require sufficient nutrients to support their rapid growth cycle. A blend of organic soil and traditional vegetated roof growing media yields the best results, but the soil will need annual amendments to maintain volume and provide sufficient nutrition.

LiveRoof Engineered Vegetated Roof Soil is composed of approximately 94% high quality inorganic aggregates by dry weight. It includes clay particles for nutrient binding and acid rain buffering, plus disease-suppressive organic material. The soil conforms to German FLL granulometric standards, filters rainwater, effectively grows LiveRoof plants, and is designed to last for many decades. Soil specifications vary somewhat by region depending on climate, water quality, and available components.