Tree grilles

Tree grilles in cast iron or steel

Tree grilles sit around the base of a tree at ground level and cover the open planting pit. They keep the footpath flat and safe, let water and air through to the roots, and protect the soil under the crown against compaction by pedestrians and bicycles. Where a tree stands in paving, a grille is often the difference between a tree that establishes itself and a tree that is struggling after a few years.

Tree grilles are chosen by municipalities and cities, designers of squares and shopping streets, landscaping contractors and managers of business parks and car parks. We supply both plain, functional versions and grilles with a pronounced pattern for a square where the streetscape matters.

Applications

• Street trees in shopping streets and on footpaths
• Trees on squares, esplanades and around stations
• Tree pits in car parks and on business parks
• Trees in courtyards, patios and covered areas
• Replacement of damaged or subsided existing grilles

Versions

A tree grille usually consists of two or four segments that together form a square or a circle. That division is deliberate: for maintenance or as the trunk thickens you remove one segment without breaking open the whole surface. The central opening can be knocked out in rings, so the grille grows with the trunk. A surrounding frame is available as an option, finishing the edge of the paving neatly and keeping the grille at the right level.

Material and technique

Cast iron is the classic material: heavy, strong, wear-resistant and able to be cast with a fine pattern. Its weight is at the same time the protection against theft and shifting. Steel, hot-dip galvanised or powder coated, is lighter and allows crisper, more contemporary shapes. Stainless steel is chosen where a high-grade finish comes first.

The safety of the slot widths matters. In places with many pedestrians, prams, wheelchairs and bicycles the openings have to be narrow enough not to trap a heel, a small wheel or a stick. Make a deliberate choice there, because this is what complaints about grilles are almost always about.

Installation and practice

A grille has to lie flat at ground level and be fully supported by a stable foundation or a load-bearing frame. Laid on loose sand it will tilt or subside and create a trip edge. Allow enough space between grille and trunk, and knock out the further rings in good time. A grille that grows into the bark strangles the tree, and that cannot be undone.

Think about maintenance too: leaves, litter and sand fill the slots and stop rainwater getting through. A blocked grille does the opposite of what you want. Include it in the annual round of the parks department.

When a tree grille is not the right choice

If the tree stands in a green area or in a generously planted tree pit, you do not need a grille and underplanting or a semi-bound surface is better for the soil. Where heavy goods vehicles run over the tree pit intensively, a standard grille is not enough and you need a load-bearing structure. The most common mistake is choosing a grille on looks and only then discovering that the central opening is too small for the tree that is going in.

What determines the price?

The price depends on the material, the size and shape, the thickness and load capacity, the pattern, the number of segments, the presence of a surrounding frame or a protective guard, the finish, and the number of units. Transport also plays a part, because cast iron grilles are heavy. Give us the tree pit dimensions and the expected loading and we will put together a concrete proposal.

Choosing the right size together

Tell us how large the tree pit is, which tree is going in and how busy the location is. We will propose a grille that suits both the tree and its surroundings. Get in touch for advice and a quotation.