· by Michael Blair, Nashville's Pressure Washing
Equipment is cheap and technique is not. A few specific questions separate a contractor who understands surfaces from one who owns a machine.
Ask about method per surface
What pressure and what solution on siding, on brick, on concrete and on the roof. The correct answer varies by surface, and someone giving one answer for all of them has told you something.
Anyone proposing to pressure wash asphalt shingles should be declined on that answer alone.
Ask about plants and water
How they protect planting — pre-wetting and rinsing is the standard and it is often skipped. Where the runoff goes, particularly on a slope toward a neighbor or a storm drain.
Whether they need access to your water and electricity, and whether that is factored into the price.
- Different method per surface, named
- Soft washing available for roofs
- Plant pre-wetting and rinsing
- Liability insurance certificate from the carrier
- What is and is not included in the quote
Insurance genuinely matters here
This is work at height with water near electrical services, and property damage from over-pressuring is a real risk. Ask for the certificate from the insurer rather than a copy.
Roof work adds a further layer — walking a roof causes damage in inexperienced hands regardless of the washing.
What is in the quote
Whether gutters are cleaned externally only or also cleared internally. Whether concrete is included or extra. Whether a post-treatment is applied to slow regrowth.
Those three account for most of the difference between quotes that look similar.