Professional exterior care
Flat roof cleaning starts with the waterproof surface, not the green growth sitting on it. A garage, extension or commercial flat roof may have felt, EPDM rubber or GRP, and each needs a compatible approach. OOR External assesses the covering and access before discussing whether cleaning is appropriate.
Request a free quoteA flat roof has a slight fall to move rainfall towards its drainage points. Leaves and moss can interrupt that route, but a puddle may also indicate a problem with the fall or the roof itself. Cleaning can address accumulated debris; it cannot correct a sagging deck, a failed seam or a leaking junction. Report those concerns before agreeing any work.
Felt often has a mineral finish that can look gritty beneath moss. That surface should not be stripped away in pursuit of a uniform colour. An old garage roof with curling laps, splits or exposed areas needs a roofer's opinion before anyone disturbs the growth. The condition underneath matters more than getting every patch immediately clean.
Removing loose debris is different from scraping attached moss. The proposed method must respect the roof system and its maintenance guidance, particularly at overlaps and along the perimeter. Tell Jordan if you know when the felt was installed or whether repairs have been made, without climbing up to investigate.
EPDM is a rubber membrane; GRP is a glass-reinforced plastic roof finish. Neither should be treated as if it were a concrete paving slab. Seams, trims and details around outlets need particular attention. Any cleaning product must be suitable for the identified system rather than chosen solely because it removes algae on another material.
From the ground, note lifted edges, obvious splits or damage around a rooflight. If the covering is uncertain, say so in the enquiry. Assessment can establish what information is needed before a cleaning plan is offered, rather than guessing from the colour of the roof.
A low roof beneath trees can receive leaves throughout the growing season as well as autumn. Shelter from adjoining walls slows drying, while small depressions can hold moisture and fine debris. Those conditions give moss a foothold, even on a roof that is not leaking. Garage roofs behind a house can therefore behave differently from the main pitched roof.
The important question is where water goes. Growth around an outlet may restrict drainage, while staining in a puddle may point to standing water elsewhere. These observations guide the discussion; they do not establish whether the roof is watertight.
Low height does not make a garage roof safe to walk on. The supporting structure and covering may be fragile, and an edge can still cause a serious fall. Access is considered before work is agreed. Do not step onto the roof or lean a ladder against a gutter to obtain a photograph.
During cleaning, loosened material must be collected rather than pushed into the drainage system. Outlets and gutters are considered with the roof, and nearby doors, paths and planting need protection. For business premises, the area below is planned around staff movements and deliveries.
Biocide can be discussed separately where the covering and treatment are compatible. It is not a waterproofing repair, and no treatment changes a defective roof into a sound one. The quotation should distinguish debris removal, cleaning and any optional treatment, so you can see what is proposed.
Send an overall view from a safe position, the postcode and any information about the membrane. Explain whether your concern is falling moss, a blocked outlet or a leak. Jordan can then discuss a free quote or advise that a roofer should assess the problem first.
Tell Jordan about the property and the work required.