If you watch someone quote an exterior clean properly, most of what they do looks odd. They knock on walls with their knuckles. They push a screwdriver into the base of a post. They lift a corner of something. They spend a long time looking at the ground at the bottom of a wall.
Very little of it is about dirt. It is about whether the surface in front of us will survive the thing we are being asked to do to it.
Tapping render and cladding
The first thing, and the most informative.
Sound render rings solid. Render that has delaminated from the substrate knocks hollow — drummy, in the trade — and that section is held on by friction and habit. Run a lance across it and it comes off, which turns a wash into a repair and an argument about who caused it.
The same test applies to stone cladding, tiled external walls and any applied finish. On cladding the consequences are worse because the pieces are heavy.
We tap the whole accessible elevation, not a sample. Drumminess is usually localised around a failure point — a leaking sill, a cracked parapet, a spot where water has been getting behind for years. More: cracked render and stone cladding.
Looking at the ground, not the wall
The base of a wall tells you what the wall is doing.
Orange or sandy grit accumulating at the bottom of brickwork means the faces are fretting, which means salt is crystallising inside the masonry and taking the surface apart from within. White powdery bloom means efflorescence and active moisture movement. Both point at a water problem, and washing a wall with a water problem accelerates it.
Flaking paint collecting in a garden bed says the coating has failed, which changes what a wash will produce. More: fretting brickwork and efflorescence on brick.
Probing timber
A screwdriver or an awl into the base of posts, the ends of bearers, the bottom rail of a gate, anywhere timber meets ground or stays damp.
Sound timber resists. Rot gives. It is a crude test and it is decisive, because a deck with soft bearers should not have a person and a machine standing on it, and a pergola post that is punky at the base is a structural question rather than a cleaning one.
We also check fixings. Rusted post bases and corroded brackets are common on coastal properties and are often hidden under exactly the growth we have been asked to remove. More: cleaning a pergola.
Identifying the material, properly
What the owner calls it and what it is are often different, and getting it wrong is how stone gets ruined.
Sandstone or reconstituted stone. Limestone or travertine, both carbonate and both etched permanently by acid. Porcelain or natural stone, which look similar laid and behave nothing alike. Colorbond or unpainted Zincalume. Timber or composite decking, where the composite has a warranty with cleaning conditions attached.
And the pre-1990 question on any fibre cement sheeting, which decides whether a machine goes near it at all. More: fibro cladding and composite decking warranties.
The water path
Where does the runoff go, and what is downhill of it.
We look for stormwater pits, the fall of the driveway, garden beds that will take the volume, the pool, the neighbour’s property at the low end, and whether there is a rainwater tank connected to the roof we are about to treat.
The tank is the one with real consequences, because treating a roof above a connected tank contaminates drinking water. It comes off before work starts and stays off through the first substantial rain. More: tank-fed properties and where the dirty water goes.
Electrical
External power points, garden lighting, pool equipment, the meter box, anything with a cracked cover or a missing seal, and overhead service lines near the work area.
Damaged external fittings get photographed and flagged, and we do not wash around them until they are dealt with. Water and compromised outdoor electrical is the fastest way for a cleaning job to become a serious incident. More: the electrical check.
The openings a wash must never target
Weep holes in brick cavities, subfloor vents, and the gaps around window and door frames.
Weep holes exist to let the cavity drain and breathe. Driving water into them puts it inside the wall, which means damp plaster inside the house a fortnight later and a problem nobody connects to the wash. Subfloor vents the same, with mould underneath.
We note them and work around them. More: weep holes and subfloor vents.
The roof, from the roof
Nobody can assess a roof from the driveway. If the quote involves roof work, someone goes up or gets eyes on it properly.
What is being looked at: tile condition and brittleness, ridge bedding and pointing, flashings, valleys, whether there is sarking, the state of the gutters and whether they are holding water, and whether the roof will carry foot traffic at all.
A fair proportion of roof inspections end with a recommendation to get a roofer first. More: does roof cleaning damage tiles and rusting gutters.
Access and the logistics nobody quotes for
Where the vehicle goes, how far the hose runs, whether there is a gate wide enough, how many steps, whether the side passage is passable, whether the neighbour’s permission is needed to reach an elevation, and where the tap is.
This is frequently the largest cost in the job and it is entirely invisible in a photo. More: access and steep blocks.
What comes out of it
A quote that names the method per surface, the exclusions, and the things found that are not cleaning problems at all — the cracked tile, the corroded bracket, the drummy section, the external outlet that needs an electrician.
Photographed, written down, and handed over whether or not the job goes ahead. The list of what is wrong with a building is useful to its owner regardless of who ends up doing the work.
