• As of January 1, 2018 The brand new logo that was created and released in 2017 will be the only official logo in affect and allowed to be used on any electronic media however, any such media like truck wraps, stationary, and postcards will be grandfathered in. Contributing Members will be allowed to use the UAMCC logo in any advertising. Permission to use the logo otherwise must be in writing. Logos used in electronic formats (ie: Websites, forums, etc.) must be linked back to the member’s profile in the UAMCC directory. Contributing Members are members that are paid and current with their dues. Please contact info@uamcc.org with any questions.

Concrete Roof Cleaning Guide

Ryan Cash

UAMCC Associate Member
How do you clean a concrete tile roof?
Can you pressure wash a concrete roof?
Should you soft wash a concrete roof?
How do you clean a clay tile roof?

There is a lot of debate in the exterior cleaning industry about the proper way to clean a concrete roof. Some contractors will tell you that it’s ok to pressure wash them, others will say that you should only ever soft wash them.

But what’s the truth??

Like everything else, the best way to find the real answer is to go straight to the manufacturers.

Most of the large manufacturers are part of an organization called the Tile Roofing Industry Alliance.

Their official response to the proper cleaning procedure is below:

“The cleaning of tiles with pressure washers is a common practice as regular roof maintenance. Since roofs are slippery when wet, the work should be performed by a qualified roofing professional. The use of diluted chlorine can be used to help remove the final algae that might be present, but we have seen just plain water used as well. The pressure washer should not be above 1300 psi as it can create surface wear. The dirt, algae or moss that grow on the surface of the tiles are not affecting the condition of the tiles. It is more an aesthetic issue that homeowners wish to remove.”

5 of the Top Manufacturers of concrete tile roofs have also released specific directions for their own products, however they are all consistent in saying you can use a pressure washer at around 1200-1300 PSI or you can soft wash with sodium hypochlorite.

You can find their specific cleaning guidelines on their individual websites:
So knowing that you CAN properly soft wash or pressure wash a concrete roof, how do you decide?

The main considerations when choosing whether to soft wash or pressure wash a concrete roof are:

  1. Can you safely walk to the roof?
  2. Can you walk the roof without breaking tiles?
  3. How long will each process take?

If you choose to go the route of Pressure washing a concrete roof you need to be keenly aware of the risks you are taking by walking the roof. Pressure washing will require you stepping on almost every part of the roof. You must be able to do this safely by using proper fall protection.

Some owner operators may say that OSHA guidelines don’t apply to them since they don’t have any employees. Although technically correct, I believe it’s equally important to be safe as an owner operator because if you fall and get injured, that’s it. You have now lost your sole source of income and livelihood. Setting up fall protection, if properly trained, only takes about 5 minutes. So it’s absolutely worth getting properly trained if you decide to walk a roof. Not only is it financially responsible, but it could save your life.

Another consideration in pressure washing is tile breakage. Although it’s possible to walk tile roofs without breaking tiles, you must have the knowledge and capabilities to do it.

Finally, it's important to understand the actual process of cleaning with a pressure washer will take a long time. Pressue washing such a large surface with odd angles, fall protection, and varying pitches and obstructions will naturally take a considerable amount of time.

So... Regardless of whether you pressure wash or soft wash, What is the actual cleaning process?

Pressure Wash:
  1. Set up proper fall protection
  2. Adjust pressure for your system to 1200 PSI
    1. You can adjust the Pressure Regulator OR)
    2. You can Choose the Correct tips to get the correct pressure
  3. Start at Peak and work your way down
  4. Avoid walking on wet/dirty tiles
    1. Typically wet algae growth is very slippery
    2. Start at top so you can walk on cleaned tiles as you go down
  5. Rinse roof if needed

Soft Wash:
  1. Start with 3-4% SH (Work up to 6% max if needed)
  2. Light Surfactant
  3. Spray from gutter line if possible
  4. Make sure to keep roof wet while cleaning
    1. Pre-soak with water if roof is hot and SH if flashing off
    2. As concrete is porous, it will likely take more solution to clean than a standard asphalt roof.
  5. Dwell 10-15 minutes
  6. Rinse if necessary
    1. Most of the Time, Rinsing is unnecessary
    2. It may be required if there is no rain in the forecast


So What about Clay tile roofs?

Clay tile roofs actually generally have the same recommended cleaning process as concrete tiles. However, they tend to be more fragile, so we recommend against walking on them.

While you technically can pressure wash a clay tile roof at 1200 PSI per manufacturers guidelines, the best approach is to soft wash.

In general (but not always), clay and barrel tile roofs will require a stronger mix (6% Sh) to clean with a moderate amount of surfactant.

Spray from the gutter line on a ladder or set up an A-Frame ladder for lower roofs to avoid unnecessary breakage of tiles.


Both Concrete and Clay tile roofs will require more dwell time and higher concentrations of SH. Because of this and the added liabilities, contractors typically charge close to double they do for asphalt shingle roofs.

On Average, contractors will charge $0.50 per square foot and may charge up to $0.75 per square foot for more complex and difficult jobs.