Pressure Washing and Prep

Washing Is the Easy Half. Drying Is the Half People Skip

Every exterior repaint starts with a wash, and almost every homeowner assumes it is a morning of work that gets the dirt off. It is that, but the reason it matters more here than inland is salt.

Air three blocks from the sand deposits a fine salt film on everything it touches, and it builds up on a wall over years. Salt is hygroscopic, meaning it pulls water out of the air and holds it against the surface. Paint applied over a salted wall is applied over a layer that will keep drawing moisture underneath the film for as long as the film lasts. That is one of the reasons coastal repaints fail early in ways that look like the paint was defective when it was not.

So the wash is not cosmetic. It is chemical removal of contamination, and then the wall has to give back every bit of the water we just put into it.

How We Wash

Low pressure and the right detergent do more than high pressure and none. Stucco takes a wide fan tip at moderate pressure held at a distance, because a narrow tip close in will cut the sand face off the render and leave a permanent striped pattern you can read from the street for the next decade. Wood siding takes less again, worked with the grain, because forcing water up behind a lap board puts moisture exactly where it does the most harm.

Chalked coating comes off with a detergent wash and agitation rather than brute pressure. If you rub a faded wall and your hand comes away white, that chalk is a bond breaker, and anything painted over it is only stuck to the chalk. Biological growth on the shaded north side gets a proper cleaning solution and dwell time, not just a blast, because knocking the surface growth off without killing what is in the pores means it comes back through the new paint.

Windows, vents, light fixtures and irrigation controls get covered first. Plants get wet down before and rinsed after, which is the difference between a hedge that survives and a hedge that browns off on the side facing the house.

Then the Wall Has to Dry, and We Measure It

This is where the schedule near the coast diverges from the schedule everywhere else.

On a warm inland day, a washed stucco wall can be ready the next morning. Here, a north elevation washed in June with fog every night and no direct sun on it can still hold enough moisture to fail a check two or three days later. Stucco is porous and it drives water in deeper than people expect. Wood is worse, because a lap joint holds water in a cavity that no amount of surface warmth reaches quickly.

We use a moisture meter on the substrate rather than counting days off a calendar. Wood should be down in the low teens as a percentage before it is coated. Masonry and stucco get read with a non invasive meter and compared against a dry reference area on the same house, because the absolute number on masonry means less than the difference between a wall that has dried out and one that has not.

If the reading is high, we prep something else and come back to it. This is the single most common reason a job here takes an extra day, and it is also the single cheapest day you will ever buy.

Everything Else That Happens Before a Finish Coat

Scraping and feathering. Any coating that is lifting comes off back to a sound edge, and the edge is sanded so the transition does not telegraph through the new film. On pre 1978 housing that work is done wet and contained, with the debris collected, because that paint layer may contain lead and dry scraping it is not acceptable practice.

Crack repair. Hairline map cracking in older stucco gets filled with a flexible patching compound and textured to match. Structural cracks, the ones that run on a diagonal from a window corner or step through the wall, are a different conversation and we will tell you when what you have is movement rather than a surface issue.

Caulking. Every joint where two materials meet gets checked. Old sealant that has gone hard and split is cut out rather than caulked over, and the new bead is tooled into the joint and given time to skin before anything goes over it. Caulk that is topcoated too early will split along the middle and the crack will read as a fault in the paint.

Priming. This is not one product. Bare wood wants a stain blocking primer or the tannin will bleed through a light finish coat within weeks. Chalky or glossy surfaces want a bonding primer. Fresh stucco or patched render wants a masonry primer that can handle alkalinity. Using a general purpose primer for all three is the shortcut that produces most of the callbacks we get asked to fix.

Why We Sell the Prep Rather Than Hide It

Prep is usually the majority of the hours on an exterior repaint, and it is the line homeowners ask us to trim because it is the part with nothing to show at the end of the day. We understand the instinct. We also know what the alternative costs, because a fair share of our work is stripping somebody else’s coating back off a wall it never properly stuck to.

If you want a cheaper number we would rather reduce the scope, one elevation this year and the rest next, than reduce the preparation on all four.

Call (424) 652-7274 and we will tell you what your walls actually need.