Hot Tub Surrounds and Enclosures

Constant moisture makes it a growth site

Splash-out, evaporation and condensation keep the surrounding deck or concrete damp almost permanently. Algae and biofilm establish quickly, and on a smooth surface that becomes genuinely slippery. This is a safety issue rather than an appearance one, particularly on composite decking which gets very slick.

Treated water leaves mineral behind

Spa water carries treatment chemicals and a high dissolved mineral load, and it is often hot when it splashes out. It evaporates fast and leaves a crust on the surround, on any glass enclosure, and on the underside of the cover. That deposit is mineral rather than dirt and does not rinse off.

Covers hold growth underneath

The underside of a cover sits in warm, humid, dark conditions permanently, which is close to ideal for mould and mildew. Covers also absorb water as the vapour barrier degrades, which is why an old cover gets heavy. A cover that smells is telling you something that cleaning the top will not fix.

What method suits it

Soft washing handles the biofilm and organic growth without driving water into decking joints or damaging composite surfaces. Mineral crust on glass and surrounds is a separate treatment. Aggressive pressure on composite decking permanently roughens it, which then holds more growth than before.