What pools and car washes share

Pool decks and car washes look like different places, but they ask much the same of grating: water most of the time, chlorine or salt, bare feet or thin soles, fast drainage and frequent cleaning. The panel must survive the water and still be safe to stand on.

Pool water carries disinfectant, while car-wash water carries detergents, wax and grit. Both leave residue on the grating; the residue dries to a film and turns slippery again when wet. The open area and surface finish decide whether that residue can be washed away.

Both are public or semi-public spaces, so appearance and feel are judged directly. Fast-fading colour, sharp surfaces and rough edges all become complaints. Weighing durability and user experience together is more realistic than comparing price alone.

Chlorine and salt water resistance

Pools are usually disinfected with sodium hypochlorite, calcium hypochlorite or a salt chlorinator. Hypochlorite is a strong oxidizer; the concentration is low, but long contact ages the resin surface. Salt-chlorinated pools carry more salt, and chloride is a greater threat to metal parts.

Chlorine resistance depends on the resin. Isophthalic resin suits a normal pool; for spas, salt pools and high-dose disinfection, vinyl ester is safer. Check the resin maker's resistance table for the actual concentration and temperature.

Salt and chlorine attack fasteners more visibly than grating. 316 stainless performs well in normal pool water but can still pit at high chloride, low pH or in permanently wet pockets. Fasteners should be easy to inspect and replace.

Wet slip resistance and bare feet

Slip requirements at a pool edge are finer than on an industrial floor. Bare feet are sensitive to grit, so coarse grit feels abrasive; fine grit is not grippy enough when wet. Medium grit with rounded grains and controlled embedment is the usual compromise.

Car washes lean towards soles and tyres. Staff wear work boots, vehicle tyres bring water in, and the surface has to take tyre shear. The anti-slip pattern must not stand too high, or tyres slip and damage it.

Wet and dry slip resistance are two separate sets of data. A pool edge is almost always wet, so selection should rest on wet performance. To choose a surface for bare feet and wet duty, see slip-resistant surfaces for bare feet

Drainage and open area

Pool drainage is sized on overflow, rainwater and washdown; a car wash adds the flow from pressure washers. Open area, channel width and slope must be calculated together, not chosen by picking a panel that looks open.

The direction of the openings affects drain speed. When bearing bars run across the flow, water piles up at each bar and drains more slowly; laying the bars with the flow is smoother. Corners in the channel should be shaped to prevent silt pockets.

Grit and wax in a car wash block the openings. Openings that are too small blind over within days; openings that are too large lose comfort and slip resistance. Car-wash bays can use a more open pattern with narrower bearing bars, backed by regular washing.

The channel under the grating needs inspection space. Drain outlets, silt traps and lift pumps should be reachable through the grating openings, so cleaning does not mean lifting the whole run.

Colour and UV stability

Both settings are sensitive to colour. Pool decks often use white, light grey or blue to sit with water and paving; car washes use dark grey or black to hide dirt. Choose for how the colour will look after fading, not only when new.

Colour stability in FRP depends on resin, pigment and surface protection. In strong sunlight, pale colours stay presentable longer: dark surfaces absorb heat, cycle harder and show colour difference more. A UV-resistant coating extends colour life.

Colour also carries safety information. Pool depth zones, steps and edges can be marked in different colours; car-wash lanes and pedestrian areas can be separated the same way. Colour fastness and the permitted colour difference should be agreed on the order. For leisure-sector practice, see pool and leisure decking

Fixings, edge trim and thermal movement

Pool-side grating moves with temperature. FRP expands more than steel, and long runs outdoors with wide temperature swings grow noticeably. Fixings should allow sliding at one end, or leave gaps between sections.

Edge trim should cover the panel edge so glass fibre is not exposed. With bare feet at a pool, burrs and sharp edges are unacceptable. Trim should match or harmonise with the panel colour and resist chlorine. Where the trim is fixed with screws, use stainless screws and seal the holes.

Fixings should sit below or flush with the surface so they cannot trip anyone. Car-wash floors take tyre loads, so fixings must also resist horizontal thrust rather than relying on self-weight.

Liftable panels need handles or lifting holes. Without them, maintenance staff lever panels up with a bar and quickly damage the edges. Handles should be flush with the surface and not affect walking.

What a car wash adds

A car wash carries a wider chemical list than a pool. Pre-soaks, foam, wax and wheel cleaners may be acidic or alkaline, and some contain fluorides or surfactants. Select the resin against the most aggressive product, not against tap water.

Car-wash loads include tyre impact and concentrated loads. When a vehicle drives onto the grating, the wheel load passes through the tyre, so span and supports must be checked against the actual vehicle. Grating should not be laid directly on soft or uneven ground.

Winter de-icing salt is another factor. In northern car washes, salt water and grit are carried onto the grating in winter, with chloride levels well above a pool. Raise the resin grade and increase rinsing frequency in these sites.

Selection and maintenance

The inquiry should state the setting, water quality, chemical list, load, span, drainage flow, colour and slip requirement. Pools and car washes differ enough that one specification cannot cover both.

Confirm resin type, anti-slip surface, open area, panel depth, edge sealing and fastener material. Public projects may also need slip-class certification and a material statement.

• State the setting, water quality and chemical list.
• Check load against the actual vehicles and crowds.
• List colour, slip and edge trim separately.
• Buy spares and fasteners from the same batch.

Daily care is mainly rinsing. Flush chlorine and detergent residue before it crystallises or concentrates, and check fasteners every six months, replacing any with rust points. To size a panel by span and open area, see FRP grating specifications