Complete Exterior Cleaning Guide for Boston Homes

House Siding: Soft Wash, Not Pressure

Whether the house is vinyl, wood clapboard, fiber cement, or brick, the correct cleaning approach is soft wash — low pressure (500–800 PSI) with appropriate biodegradable cleaning chemistry that kills mildew and algae at the root. High-pressure washing damages siding, forces water into wall assemblies, and strips paint on wood and fiber cement surfaces. Soft wash cleaning in Boston should be done every 2–4 years depending on shade and exposure conditions, and always before any exterior painting. PWNA exterior cleaning standards →

Roof: Soft Wash Only

Asphalt shingle roofs should never be pressure washed — it strips granules and voids warranties. Soft wash with a sodium hypochlorite solution applied at under 500 PSI kills algae and moss at the root without damaging granules. Most Boston roofs need attention every 2–5 years depending on tree coverage and sun exposure. North-facing and heavily shaded roofs develop algae significantly faster than south-facing sections. ARMA roof cleaning guidelines →

Decks and Fences: Medium Pressure with Wood Cleaner

Wood decks and fences require an oxalic acid-based wood cleaner applied before pressure washing to remove gray oxidation and mildew at the cellular level. Pressure washing follows at 1,000–1,500 PSI with a fan nozzle working along the grain. Both require 48–72 hours of drying before any stain application. Decks typically need cleaning and restaining every 2–3 years in Boston's climate; fences every 3–4 years for vertical surfaces. TWP wood cleaning products →

Driveways, Walkways, and Patios: High Pressure with Surface Cleaner

Concrete, asphalt, and paver surfaces handle 2,500–3,000 PSI cleaning with a surface cleaner attachment. Pretreat with appropriate cleaner for the contamination type: degreaser for oil stains, oxalic acid for rust and efflorescence, sodium hypochlorite for biological growth. Surface cleaner attachments produce uniform results without the striping of a wand nozzle and minimize sand loss from paver joints. ICPI paver maintenance →

Gutters: The Often-Forgotten Surface

Gutters accumulate biological growth on the exterior face (the visible front) that responds well to soft wash cleaning during house washing. More importantly, gutters need interior cleaning — removing leaves, debris, and compacted deposits — at least once annually in late fall after leaf drop. Clogged gutters cause ice dam formation, fascia rot, and foundation water infiltration. Gutter cleaning is the highest-ROI maintenance investment on a Boston home because it prevents the expensive consequences of failed drainage. This Old House gutter maintenance →