Tree Grates are Functional and Fashionable

Tree grates are available in cast iron, aluminum or bronze and cast from 100 percent recycled metals. Steel frames and preformed steel troughs are also available.

Tree grates are not only aesthetically pleasing but they are also functional for pedestrian safety.

Ironsmith, of Palm Desert, Calif. offers standard designs and sizes in compliance with The Americans with Disabilities Act, as all manufacturers of tree grates do. Their grates can accommodate tree well sizes to 12 feet and tree openings to four feet. For special projects, Ironsmith offers custom sizes and designs, and can provide design drawings in AUTOCAD R14 or DFX format.

Tree grates are offered most often in cast iron or aluminum. Most patterns can be provided with, or later expanded to a variety of tree openings. Tree grates can be used in indoor or outdoor hardscape designs whenever trees are planted. Many designs allow the tree opening to be enlarged in increments to accommodate the growth, protecting the tree from injury.

They are also designed to protect people from injury.

Areas subject to high foot traffic require the added safety of tree grates with smaller openings of 1/4" or 3/8", known as "pedestrian proof." Guidelines established by the national Architectural and Transportation Barriers Compliance Board that became law as part of The Americans with Disabilities Act of 1990 allows slots not more than 1/2" square or round where gratings are located in walking surfaces.

"Unguarded tree wells and older style grates with larger openings can present serious liability problems," said Kathy Steinhauer, a representative for Ironsmith tree grates in Las Vegas. "Usually court ordered mandatory changes, plus five and six figure fines."

Narrow slots also help to prevent litter from accumulating in the tree well and minimize weed growth.

These grates with narrow slots allow canes, wheelchairs, crutches and high heels to travel over the grates without falling into the tree well.

Grates are also functional at night by adding illumination to them. Lightwells are an option on many of the grate designs. Removable covers allow for the installation of subgrade lighting units. Covers are offered in clear Lexan (polycarbonate) or as a small grate and are always bolted to the main grate to prevent loss.

Not all grates are made of metal. NDS of Lindsay, Calif. offers tree grates molded from recycled high-density structural foam plastic. Some major benefits of a plastic grate is that they will never rust, become brittle in cold weather, and are unaffected by road salt.

The NDS grates are heavy duty but lightweight. One person can install them, as they have an average weight of less than 40-pounds-per-grate. If a tree becomes too big for the grate, a standard saw blade can be used to accomodate growth.

If the plastic grate is concrete surrounded, you should allow for 3/16" expansion space between the vertical edge of grate and concrete. The ledge should be 2 inches below the concrete or tiled surface and extend 2-3 inches. It is important to remember that the ledge must be level to prevent rocking of grate.

If the plastic grate is ground supported, existing dirt should be removed up to a depth of 8". A mixture of compactible fill sand and 3/4" stone firmly compacted to a depth of 4". Approximately 2" of loose stone should be added evenly across the bed.The grate should then be imbedded slightly in 3/4" stone.

To secure a plastic grate, place the grate evenly on the ledge and drill 1 1/2" into the ledge through the optional pre-drilled holes on the corners of the tree grate. NDS recommends securing the grate to the ledge with #14 x 3-1/4 FH tap-con screw.

For security bolting on a metal grate the Neenah Foundry Company of Neenah, Wis. offers that the use of a "Blue Devil" tamperproof socket screw manufactured by Safety Socket Screw Corporation of Chicago, Ill. be used for flush mounting.

If flush mounting is not a requirement, a pent head bolt may be used. Some tree grates with sufficient thickness can be bolted flush with a recess for the bolt head.

The Neenah Foundry Company suggests that as a tree grows and the trunk becomes larger, the grate opening can be enlarged in increments. The suggested method to accomplish this is to use an abrasive cutting wheel and notch the radial spokes at the junction of the expansion rings. If a cutting wheel is not available, they suggest using a power hack saw or a sharp cold chisel.

Tree grates in areas with high foot traffic should follow guidelines established by the National Architectural and Transportation Barriers Compliance Board which states that slots not more than 1/2" square or round where gratings are located in walking surfaces.

Tree grates can be customized as well. Many tree grate manufactureres offer decorative markers that can be engraved in or attached on a grate. Many cities like to use a city seal or a design that reflects the city along with the year the city was founded. Corporations or large event venues will often put their respective logos on grates in the area surrounding their building.

When a Landscape Architect is looking to specify a tree grate they can contact the manufacturer and request shop drawings that can be submitted for the LAs approval. These drawings will include the requested grate design and opening sizes.

Remember: the most important thing to keep in mind is that pedestrian safet must always be considered first when specifying tree grates.