Two render quotes for the same house can differ by a large margin, and the reason is rarely that one contractor is more expensive than the other. It is that they are pricing different jobs — different render types, different access, and sometimes a repair the other one has not spotted yet.
Why there are no prices on this page
Because a figure printed here for a wall nobody has seen would be invented, and an invented number is the one thing a customer will hold a contractor to later. What we can do honestly is explain what the price actually depends on, so a quote makes sense before you accept it rather than after.
Send a photo of the worst elevation and a close-up of the finish, and the quote comes back specific to your house rather than to a category of house.
What actually moves the price
How many elevations, and how tall. One gable is not the same job as all four walls of a two-storey house. Height changes the equipment needed and how it is rigged, which changes the time far more than the extra wall area does.
Access. A detached house with clear ground on every side is straightforward. A terrace with a shared or locked side return, a wall backing onto a neighbour’s garden, or a gable only reachable from scaffold all add time before any washing starts.
Render type. This is the biggest single variable and the one most quotes do not separate out. K-Rend and other silicone through-coloured renders take longer to assess and must be soft washed at low pressure with a longer dwell time. Painted render cleans faster but needs a condition check first — see below. Pebbledash holds growth deep in its texture and takes noticeably longer to treat evenly than a flat render of the same area. Brick is the quickest surface but the mortar joints set a lower pressure ceiling than the brick itself would allow.
Whether the paint is sound. On a painted wall, a contractor who checks the coating’s condition before quoting is pricing the actual job. One who does not is pricing a wash that may turn into a much bigger conversation on the day, once flaking or chalking paint comes away with the growth.
How wet the wall has been. A shaded, damp elevation carries heavier, longer-established growth than a wall that dries out between showers, and thicker growth takes longer to treat regardless of the render underneath it. If the wall is wet because of a fault rather than just its aspect — an overflowing gutter, a leaking downpipe, ground built up above the damp course — that is worth fixing at the same time, because it is what decides how long the clean actually lasts.
Comparing two quotes
Get both in writing and check they name the same render type and the same access — a quote given over the phone with no photograph has usually assumed the easiest version of both. Check whether either quote mentions the paint condition, if the walls are painted; a contractor who has looked closely enough to flag that is pricing the job rather than the postcode.
And check what happens to the soffits, fascias and uPVC while the equipment is already up. On most houses that is a small addition to a render job and a much larger one booked separately later.
Why the cheapest quote is a warning here specifically
On most exterior surfaces a low quote just means less time spent. On render it usually means one thing: pressure instead of soft washing. Pressure strips growth off a wall in a fraction of the time a proper soft wash takes, which is exactly why it is cheaper to offer and why it looks like the better deal.
It is also close to irreversible on a through-coloured render. Pressure removes the surface texture along with the growth, and because the colour runs through the material rather than sitting on top of it, the damaged patch cannot be patched to match — the fix is re-rendering the elevation. A quote considerably below the others for the same render type is worth asking about directly: “Are you pressure washing this, or soft washing it?” is a fair question to put to any contractor, and the honest answer is easy to give.
Where the surface really does suit pressure — much of the driveway and patio work covered in soft washing vs pressure washing — a cheaper, faster quote is not a red flag at all. Render is the specific case where it is.
For the method itself, rather than the price of it, render and house washing sets out how a wall is actually cleaned and why pressure is never part of it.