Roof Cleaning & Moss Removal in Newcastle

Moss needs shade and damp, and Newcastle's coastal climate supplies plenty of the second, so it is the shaded pitches that suffer worst — a north-facing slope, a roof tucked behind a taller neighbouring terrace, or one shaded by a mature tree in a Heaton or Jesmond garden. A south-facing pitch on the same house, drying out in the sun for a few hours most days, can stay largely clear while the shaded side thickens up year on year. That is why two roofs on the same street, and sometimes the two pitches of the same roof, end up in very different states.

It is more than cosmetic. A moss cushion holds rainwater against the slate or tile long after a clean roof would have shed it, and that trapped moisture works into hairline cracks and softens old mortar fillets around ridges and chimneys over time. Moss also washes downhill in wet weather and collects in valleys and gutter outlets, which is a common cause of a blocked valley backing up under the felt. Left long enough it accelerates wear on the covering rather than merely sitting on top of it.

High-pressure jet-washing strips the weathered surface off natural slate and concrete or clay tile, and the force of the jet can drive water up and underneath the overlapping courses instead of just rinsing the top surface. On an older Newcastle roof laid to BS 5534 mechanical fixings, that pressure risks loosening slates that are otherwise perfectly sound. Manual scraping followed by a low-pressure soft wash lifts the moss off without eroding the covering or disturbing how it is fixed down, which is why it is the method used on every job here.

A soft wash uses a fraction of the pressure of a jet-wash, applied mainly to rinse away spores, algae film and loose residue once the bulk of the moss has already been scraped off by hand. A biocide is applied at the same stage to slow how quickly moss re-establishes on a shaded pitch, rather than relying on force alone to strip the surface. The combination gets the roof genuinely clean without the abrasive damage a high-pressure lance causes to slate and tile finishes.

Done properly, no — the moss is lifted by hand working with the lay of the slate, from a scaffold or roof ladder rather than by standing directly on the covering, so weight is never concentrated on individual slates or their fixings. The bigger risk to an older roof is actually the opposite: leaving thick, waterlogged moss in place for years, which is what softens fillets and works into hairline cracks. A careful manual scrape is far gentler on 20- or 30-year-old Welsh slate than a high-pressure jet ever is.

It depends entirely on the pitch's orientation and shade, which is exactly why a general rule tends to mislead — a shaded, north-facing roof in Heaton or Gosforth behind a mature tree can need attention every few years, while a sunnier, more exposed pitch may go far longer without visible growth. Biocide treatment after a clean slows regrowth on the pitch that produced it, but it does not stop moss returning altogether if the shade and damp that caused it are unchanged. The honest answer only comes from looking at your specific roof, which is what the free survey is for.

No, and we will not pretend it does — moss returns wherever a pitch stays shaded and damp, because those conditions haven't changed just because the roof has been scraped and washed. What a proper clean plus biocide treatment does is remove the existing growth and slow how quickly new growth re-establishes, buying real time before the pitch needs attention again. Anyone promising a permanent fix on a genuinely shaded roof isn't being straight with you.

Once the moss is scraped and washed off, the roof is walked while the access is already up, checking specifically for what the moss cushion was hiding — a cracked or slipped slate, a tile that has moved, and mortar fillets or pointing around chimneys and ridges that have softened underneath the growth. Anything found is photographed and written down in plain terms, whether that's nothing at all or a repair worth booking separately. It's included in the price of the clean, not billed as an extra.

There's no single figure that fits every roof, because the price depends on the roof's size and pitch, how established the moss is, and how much of the covering needs scraping versus a lighter soft wash — a roof cleaned every few years is a different job to one left untouched for a decade. We price it honestly at the free survey rather than guessing over the phone, and the written quote is fixed before any scraper touches the slate. There is no obligation to go ahead once you have the number.

If a full re-roof or re-cover is genuinely close, a clean is usually not worth paying for on its own, since the covering coming off anyway makes the moss moot — see roof replacement and re-roofing for how that decision gets made. But if the roof is sound and a re-roof is years away rather than months, clearing the moss now protects the covering you already have and stops it feeding blocked gutters and valleys in the meantime. We will give you a straight view at survey on which situation yours is in, rather than selling a clean you don't need.