Taking care · 4 min read
A good exterior paint job near the water will last years longer if it gets a small amount of attention, and the attention required is genuinely small. A gentle wash once or twice a year and a ten minute look around annually is most of it.
What follows is what the coast does to a coating, what to do about it, and how to tell the difference between paint that is weathering normally and paint that is failing.
Let it cure before you treat it as finished
Touch dry and fully cured are not the same thing. Most trade paints are dry to touch within hours and can be recoated the same day, but the film keeps hardening for weeks after that as it reaches its final durability.
During that window, go easy. Do not scrub marks off, do not tape anything to the surface, and try not to lean ladders or push furniture hard against fresh work. The exact timing depends on the product, the temperature and the humidity, so ask us for the number that applies to the paint on your job rather than assuming.
What salt air actually does to a coating
Salt travels a long way inland as a fine aerosol, settles on every surface it reaches, and holds moisture against the coating. Combined with hard afternoon sun and the humidity that sits over Lake Macquarie, that is what produces the chalky, faded look on west and north facing walls a few years before the shaded sides go.
The counter intuitive part is that sheltered surfaces often cop it worse than exposed ones. A wall under a deep eave, the back of a carport, the underside of a balcony: these collect just as much salt as anywhere else, but they never get rinsed by rain, so the deposits simply build up.
Salt does not need rain to reach a wall, but it does need rain to leave one.
How to wash it, and how often
A gentle wash once or twice a year does most of the work, and the sheltered spots above are the ones that actually need it. Closer to the surf, or on a very exposed block, more often is better.
Use a soft brush or a sponge, plain water or a mild detergent, and rinse from the top down so you are not dragging dirt across clean paint. Avoid a pressure washer on painted surfaces. It will drive water behind weatherboards and into joins, and on any coating that has started to lose its grip it will take the paint off rather than the salt.
The ten minute check worth doing once a year
Walk the outside of the house slowly and look at the places where water sits or runs. Small problems found here are touch ups. The same problems found in three years are a repaint.
What to look at
- Window sills and the bottom rails of frames, where water pools
- The ends and joins of any exposed timber, which drink water first
- Caulking around windows, doors and trim, for gaps opening up
- Nail heads and metal fixings, for rust bleeding through the paint
- Gutters, downpipes and anything overflowing onto a wall
- The shaded southern side, for mould starting as a grey or black film
- Decks and handrails, which weather faster than anything else on the house
Mould on the shaded side
The southern walls and anywhere under heavy tree cover stay damp longest, and that is where mould shows up first. It usually reads as a grey or blotchy black film rather than a stain, and it is sitting on the paint rather than in it.
Wash it off rather than paint over it. Painting over mould traps a living surface under the new coating, and it will come back through. If it keeps returning in the same spot, the real fix is usually drainage, a gutter, or cutting back whatever is keeping the sun off that wall.
Small repairs beat big repaints
A chip on a window sill or a hairline split in a timber join is a ten minute fix while the surrounding paint is sound. Left alone, water gets in behind the film, the timber swells, and the paint around it lets go, which turns one sill into a wall.
Keep the leftover paint from the job, and keep it labelled with the room or the elevation, the colour, the sheen and the date. Store it somewhere that does not freeze or bake, and press the lid down properly. A tin that has skinned over is still usable if you cut the skin out cleanly rather than stirring it through.
How to tell when it is time to repaint
Paint fails gradually and gives plenty of warning. Chalking is usually first: run a hand down a sunny wall and if it comes away with a fine powder on it, the surface has started to break down. Fading, a dull flat look where there was once sheen, and fine cracking across the film all point the same way.
Flaking and bare patches mean you have gone past the easy point. Once the substrate is exposed, the next job includes stripping and priming work that a repaint a year earlier would not have needed. If you are seeing chalk and fade but no lifting, you are at the right moment to plan rather than the wrong moment to react.