Soft Wash Roof Cleaning glossary of terms & specifications
15 technical terms, material grades and Irish standards explained in plain English so you know exactly what is on a written quote.
Sorted A to Z for quick reference when comparing specifications.
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Key soft wash roof cleaning terms explained
Agricultural & Septic Tank Runoff Protection
Diverting downpipe discharge before chemical application on rural homes with private septic tanks or biocycle treatment systems so biocide or sodium hypochlorite never enters the biological percolation tank.
Alkaline Surfactant Wetting Agent
Biodegradable foaming additive mixed into a soft wash solution so the active wash clings to pitched roof slates and vertical render rather than running straight into the gutters.
Biocide Residual Biofilm Treatment (DDAC / BAC)
pH-neutral quaternary ammonium compound sprayed at low pressure after manual moss scraping that penetrates porous concrete tiles and kills algae, lichen and moss spores over 3 to 9 months.
Biological Weathering (Gloeocapsa Magma & Trentepohlia)
The airborne cyanobacteria (black streaks), red-orange algae (Trentepohlia) and crustose white/yellow lichens that colonise damp Irish roofs and pebble-dash walls.
Concrete Roof Tile Acrylic Sealer / Coating
Breathable, microporous clear or pigmented acrylic resin applied in two coats to dry, cleaned concrete tiles to restore water repellency and slow future moss rooting.
Controlled Manual Moss Scraping
Removing heavy moss cushions dry from roof tiles using shaped profile scrapers attached to telescopic carbon-fibre poles from a scaffold tower or cherry picker—without blasting water under the tile laps.
Downpipe Bagging & Gutter Isolation
Fitting inflatable bungs or temporary polythene diverter sleeves onto rainwater downpipes before roof washing so all moss debris and wash solution are collected in barrels rather than entering storm drains.
Fibre-Cement Slate Delamination Risk
Older fibre-cement and artificial slates soften and flake if hit with a high-pressure turbo nozzle; they must only ever be hand-scraped dry and treated with low-pressure biocide.
HSA Working at Height & Roof Ladder Protocol
Health and Safety Authority compliance requiring mobile scaffold towers, MEWP cherry pickers or ridge-hooked aluminium roof ladders and harnesses—never walking directly on wet slates or fragile tiles.
Low-Pressure Soft Wash Pump (40–100 PSI)
Dedicated 12V or air-diaphragm chemical delivery pump that applies cleaning solution at garden-hose pressure (under 100 PSI) instead of a 2,500–3,500 PSI pressure washer.
Natural Blue Bangor & Killaloe Slate Care
Dense metamorphic natural slates do not absorb water like concrete tiles, so soft washing and gentle lichen neutralisation restore their original blue-black colour without needing any surface sealer.
Plant & Lawn Pre-Wetting and Neutraliser
Thoroughly soaking flowerbeds, hedging and lawns with fresh water before and after soft washing and applying sodium thiosulphate neutraliser to protect garden plants.
Porous Interlocking Concrete Tile Granules
The factory surface layer on concrete roof tiles that high-pressure jet washing strips away in minutes, leaving rough, pitted concrete that holds standing water and regrows moss twice as fast.
Sodium Hypochlorite (SH) Soft Wash Blend
Diluted, surfactant-buffered sodium hypochlorite solution (typically 1% to 3% active strength on render and 2% to 4% on heavily stained concrete tiles) that oxidises organic stains on contact.
Two-Stage Scrape-and-Biocide Method
The gentlest long-term roof cleaning method in Ireland: 1) dry-scraping 95% of loose moss from the tiles and gutters, then 2) saturating the roof with slow-acting residual biocide that keeps the roof clean for 3 to 5 years.
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Questions people ask
How much does soft wash roof cleaning cost in Ireland?
A 3-bed semi-detached roof typically costs €300 to €1,800, a 4-bed semi €900 to €2,300, a bungalow €600 to €1,800, and a detached house €450 to €3,000+. Prices include the reduced 13.5% VAT rate.
What is soft wash roof cleaning?
Soft washing cleans a roof at low pressure (similar to a garden hose) using a biodegradable surfactant and either a sodium hypochlorite wash or a slow-acting residual biocide (DDAC/BAC), after any heavy moss cushions are scraped off by hand.
Is soft washing safer than pressure washing for concrete roof tiles?
Yes. High-pressure jet washing strips the factory protective granule layer off interlocking concrete tiles, making them porous so moss regrows faster, and can force water up under the tile laps onto the sarking felt.
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