Cleaning asphalt shingles without sandblasting the granules off

What is shingle roof cleaning?

Shingle roof cleaning means removing algae, moss and organic soiling from asphalt shingles with a method that does not strip protective granules. The industry-standard approach is soft washing - low pressure, cleaning solution, dwell time, gentle rinse. High-pressure washing can make a roof look briefly cleaner while permanently thinning the surface that keeps the asphalt alive.

How shingle roof cleaning actually works

1. 1

   Confirm the roof is asphalt and still cleanable

   Curling, widespread bare asphalt, brittle breakage underfoot and active leaks change the job from cleaning to roofing assessment. Cleaning does not resurrect a roof that is out of granules already.

   Watch forA cleaning quote with no comment on roof condition. Honest operators sometimes walk away.

2. 2

   Choose soft wash as the default on shingles

   Solution is applied at low pressure; chemistry kills growth; time does the work. Rinsing, when done, stays gentle. This is the opposite of "cut the pressure a little on the washer".

   Watch forMarketing that says soft wash while the trailer only carries a pressure washer and tips. Equipment tells the truth.

3. 3

   Foot traffic and staging discipline

   Technicians should walk with care on dry, sound shingles, avoid breaking seal strips in heat when possible, and keep traffic off fragile valleys and ridges when reach allows. Cleaning damage is often foot damage, not only water damage.

   Watch forCrews running across hot south slopes in midsummer like a sidewalk. Softened asphalt and broken bonds follow.

4. 4

   Moss versus film growth on shingles

   Thin algae films respond to treatment and weather-fade. Thick moss may need careful mechanical assistance after it is killed - never as a high-pressure substitute for dwell. Moss that has lifted tabs needs roofing judgment, not only cleaning.

   Watch forScraping dry living moss hard against granule surfaces. You will fill the gutters with roof material.

5. 5

   Plant protection and runoff control

   Same soft-wash plant discipline as any roof clean: pre-wet, cover sensitive species, manage downspouts. Shingle jobs are often larger surface areas with more runoff volume.

   Watch forOpen windows, fresh car paint in the driveway, and uncovered copper that was never discussed.

6. 6

   Aftercare and realistic colour expectations

   Cleaned shingles look more even as dead growth releases. They will not look factory-new if years of UV have already weathered the mineral surface. Document before/after honestly for HOA or resale files.

   Watch forPressure "touch-ups" offered when the fade is not instant. That is the moment granules leave.

7. 7

   Coordinate with gutters and downspouts

   Released growth and rinse water head for the gutter system. A shingle clean that leaves outlets blocked simply relocates the moisture problem to the eaves. Many quality visits include gutter attention or schedule it the same week.

   Watch forOverflowing gutters the first storm after a "complete" roof clean. Ask who owns gutter clearing in the quote.

What does shingle roof cleaning cost?

Asphalt shingle cleaning is typically priced by roof area, pitch, height and growth type. Soft-wash shingle jobs cost more than a quick blast would - that difference is the point. Steep three-story homes and heavy moss add labour. Bundle quotes should still name method and pressure approach.

See the full shingle roof cleaning cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →