Patio cleaning in Teesside
Patio cleaning in Teesside typically costs £3 to £6/m², with black spot lichen treatment on Indian sandstone quoted as an extra. Concrete slabs, natural stone and porcelain each need a different pressure and chemical approach, and pointing is checked and repaired before washing.
Black spot: the Teesside patio problem
If your Indian sandstone has small black dots that survive every jet wash, that is black spot, a lichen that roots into the pores of the stone. It thrives in exactly the damp, mild conditions Teesside offers, and it is now on sandstone patios from Yarm to Hartlepool that were laid in the 2000s sandstone boom. Pressure alone will not remove it. The spots are the lichen's anchor points, and blasting the surface just scuffs the stone around them.
The effective treatment is a dedicated black spot killer, a sodium hypochlorite based product applied to the dry patio and left to work, sometimes over two applications on heavy infestations. Only then is the patio washed. Severe cases on porous sandstone can need a repeat treatment the following season, and an honest quote will say so up front rather than promise a perfect slab on day one.
Prices and what drives them
Patio cleaning across Teesside runs £3 to £6/m², so a typical 20 to 30m² back-garden patio quotes between £70 and £180. The drivers: black spot treatment (product plus dwell time), re-pointing where joints have failed, and access, a rear patio in a central Middlesbrough terrace with no side access means carrying equipment through the house or over a wall, and quotes reflect that.
Slab type changes the method
Concrete slabs are the toughest and take a rotary surface cleaner well. Indian sandstone is softer and more porous: lower pressure, fan jet rather than turbo nozzle, and care around weathered edges. Natural limestone is acid-sensitive, so the wrong chemical etches it permanently. Porcelain is nearly non-porous and cleans easily, but the jointing compound is soft and a careless lance will strip it out. The method should follow the material, which is why a proper quote asks what your patio is made of.
Pointing and aftercare
Washing exposes failed pointing, and loose joints let water under the slabs, which lifts them over a Teesside winter freeze. Small areas can be re-pointed as part of the job; widespread failure is worth quoting separately. After cleaning, a biocide wash once a year and keeping furniture feet off the stone slows the return of algae and black spot considerably, particularly on the shaded, north-facing patios common behind the 1930s semis of Acklam and Linthorpe.