Exterior maintenance knowledge centre.

The standard advice you find online, twice a year, is written for inland properties in temperate climates. It does not transfer to an island.

Salt is the deciding factor. Airborne salt settles on glass, attracts moisture and forms a film that etches into the surface if it is left long enough. The closer a building sits to open water and prevailing wind, the faster this happens.

As a working guide: waterfront and first row properties benefit from attention every one to three months. Properties a few streets back can usually stretch to every three to four months. Sheltered inland properties may be fine at two to three times a year.

Commercial frontage is a separate calculation. Storefront glass is part of how the business presents itself, so the interval is usually driven by appearance rather than by the condition of the glass.

The practical test: look at the glass in direct low angle sunlight, early morning or late afternoon. Film and spotting that are invisible at midday show up clearly at that angle. If you can see it then, it is time.

Power washing uses high pressure to physically remove mildew, mould and organic growth such as algae. Soft washing uses a low pressure system with biodegradable chemicals to break the same growth down instead.

The distinction matters because pressure does not discriminate between the growth and the surface it is sitting on.

High pressure suits hard, durable, non porous materials: concrete driveways, pavers, stone walkways, hard boundary walls and similar. These surfaces can take the force and benefit from it.

Low pressure suits anything painted, rendered, roofed, screened or aged. Driving high pressure water into render or under roof tiles pushes moisture where it should not go, and on paint it simply strips the finish.

The failure mode people regret most is roof cleaning. A roof carrying algae streaking looks like an obvious pressure washing job and is almost never one. High pressure on tiles lifts them, breaks seals and forces water into the roof structure.

If you are unsure, the surface decides, not the equipment on hand. A competent assessment before the work starts is worth more than any technique used afterwards.

Three forces work on a Bahamian building exterior continuously: salt, humidity and ultraviolet light. Each does something different and they compound each other.

Salt is hygroscopic, meaning it pulls moisture out of the air. A salt film on a surface therefore keeps that surface damper than it would otherwise be, for longer, which is precisely the condition organic growth needs.

Humidity supplies that growth. Mould, mildew and algae are opportunistic. Give them a consistently damp surface with any organic material on it and they establish quickly, particularly on north facing and shaded elevations that never fully dry out.

Once established, the growth holds moisture against the surface permanently. On render and paint this leads to breakdown of the finish. On roofing it shortens the life of the material. On timber it accelerates rot.

Ultraviolet light then degrades whatever coating was protecting the surface, leaving it more porous and more hospitable to the next round of growth.

The takeaway is that exterior cleaning in this climate is maintenance rather than decoration. Removing growth on a regular cycle interrupts a process that is otherwise continuous.

Before a storm, the priority is removing anything that can become a projectile and identifying anything already compromised.

Walk the exterior and check: loose or lifting roof material, cracked or loose window panes, failed sealant around frames, blocked gutters and downspouts, loose fascia and soffit, and anything stored against the building that is not secured.

Heavy organic growth on a roof is worth noting at this stage. Growth holds moisture and can indicate material that has already begun to degrade, which matters when wind driven rain arrives.

After a storm, the exterior will typically carry salt spray well beyond its normal reach, plus deposited organic debris and staining from standing water.

Rinsing salt off glass and painted surfaces reasonably soon after a storm limits how long that salt sits and draws moisture. Debris left in gutters and against walls stays damp and gives growth a head start.

Damage assessment comes first and cleaning second, but the two are related: a clean surface is far easier to inspect properly than a stained one.

None of this is complicated, but doing it in advance genuinely improves the result and shortens the time the crew needs on site.

Clear the working area. Move vehicles, outdoor furniture, grills, planters and anything else sitting against the building or on the surface being cleaned.

Close everything. Windows and doors on the elevation being washed should be shut. This matters far more for soft washing and power washing than people expect.

Sort out access. Unlock side gates, clear the path around the building and make sure an outdoor water source is reachable.

Secure pets. Keep animals indoors while equipment is running and until treated surfaces have dried.

Flag problems in advance. Cracked panes, failed seals, flaking paint, lifting render and loose roof material should all be pointed out before work starts, not discovered during it.

Say what you want. If there are areas you particularly care about, or areas you would rather were left alone, mention them at the walkthrough.

There is a persistent assumption that more pressure equals a better clean. On roofing and render the opposite is true, and the damage is often not visible until much later.

Roof tiles and shingles are designed to shed water flowing downward. High pressure directed at them, particularly upward under the overlap, forces water into the structure and can lift, crack or displace the material entirely.

Render and painted masonry are porous. High pressure drives water into that porosity, and on paint it simply removes the coating along with the growth. The surface looks clean and is left less protected than before.

Soft washing works differently. A biodegradable solution is applied at low pressure, given time to dwell, and allowed to break the growth down chemically. It is then rinsed off gently.

The result takes longer to achieve on the day and requires knowing what you are doing. It also leaves the surface intact, which is the entire point.

If someone proposes high pressure on your roof, that is worth a second conversation before the equipment comes out.