What is the Best House Wash Mix for Soft Washing?

When you are looking for the "best house wash mix" you are really seeking the best concentration of bleach to use on a particular job. Additives and water will certainly help, but bleach is the primary agent. Let’s look at a practical way to determine the best house wash mix for a particular job.

You may be looking for a single silver-bullet ratio as the answer, but this is not realistic. There is no best house wash mix that is appropriate all the time. Why not? Because the variables that go into what I call the “Cleaning Equation” won’t permit it.

Elements that go into the cleaning equation for any particular job include such things as air temperature, surface temperature, water temperature, solar radiation level, age of the bleach, concentration of the bleach solution, density of the biologicals we are trying to remove, dirt contamination, and water hardness. Professional wash contractors that have been around the block a time or two know that each of these “invisible” elements have an enormous effect on the cleaning equation.

When it comes to using bleach in the building/house wash process - the most practical way to determine if you’re using the most appropriate concentration is to apply the 5-7 minute dwell time rule.  Regardless of whether you’re using a soft wash or a power wash application system, the 5-7 minutes dwell time rule still applies.

Once you apply the bleach solution to the structure’s surface, if the mold and mildew is gone after 5-7 minutes of dwell time, then the dilution is appropriate. If the mold and mildew disappear immediately, then the bleach solution is too strong. If the mold and mildew are not gone after seven minutes of dwell time, then the bleach solution is too weak.

Once you have determined the bleach concentration, you should add 1-5 ounces of Fresh Wash. When added to a sodium hypochlorite based cleaning solution Fresh Wash augments cleaning results by:

  • Allowing surface tension to be broken on the cleaning surface
  • Allowing deeper penetration of sodium hypochlorite based cleaning products into stains
  • Allowing bleaching reaction to happen at a lower overall bleach concentration
  • Allowing cleaning products to dwell (hang) longer on horizontal surfaces

It also includes rinsing agents that help fight hard water spotting, and features a masking / cover scent.

House Wash Mix*

5 Gallon Downstreaming Mix

  Water 12.5% SH Fresh Wash
Light 3 gal 2 gal 5 oz
Medium 2 - 2.5 gal 2.5 - 3 gal 5 oz
Strong 1.5 - 0 gal 3.5 - 5 gal 6 oz

X-Jet, M-Jet

  Water 12.5% SH Fresh Wash
Light 4 gal 1 gal 5 oz
Medium 3.5 gal 1.5 gal 5oz
Strong 2 - 3 gal 2 - 3 gal 6oz

50 Gallon Batch Mix

  Water 12.5% SH Fresh Wash
Light 46 gal 4 gal 6 oz
Medium 45 gal 5 gal 8 oz
Strong 44 gal 6 gal 10 oz

*Rusults may differ due to varriations in equipment used.

Roof Cleaning Mix

30 Gallon Mix

  Water 12.5% SH Fresh Wash
Light 23 gal 7 gal 18 oz
Medium 21 gal 9 gal 21 oz
Strong 19 gal 11 gal 24 oz

40 Gallon Mix

  Water 12.5% SH Fresh Wash
Light 30 gal 10 gal 24 oz
Medium 28 gal 12 gal 28 oz
Strong 26 gal 14 gal 32 oz

50 Gallons

  Water 12.5% SH Fresh Wash
Light 38 gal 12 gal 30 oz
Medium 35 gal 15 gal 35 oz
Strong 32 gal 18 gal 40 oz

60 Gallons

  Water 12.5% SH Fresh Wash
Light 46 gal 14 gal 36 oz
Medium 42 gal 18 gal 42oz
Strong 38 gal 22 gal 48 oz

70 Gallons

  Water 12.5% SH Fresh Wash
Light 53 gal 17 gal 42 oz
Medium 49 gal 21 gal 49 oz
Strong 45 gal 25 gal 56 oz

80 Gallons

  Water 12.5% SH Fresh Wash
Light 60 gal 20 gal 48 oz
Medium 56 gal 24 gal 56 oz
Strong 51 gal 29 gal 64oz

90 Gallons

  Water 12.5% SH Fresh Wash
Light 68 gal 22 gal 54 oz
Medium 63 gal 27 gal 63 oz
Strong 58 gal 32 gal 72 oz

100 Gallons

  Water 12.5% SH Fresh Wash
Light 76 gal 24 gal 60 oz
Medium 70 gal 30 gal 70 oz
Strong 64 gal 36 gal 80 oz

If you are washing vertical surfaces, you should add 1/2 to 2 ounce of EZ Cling. EZ Cling is formulated to maximize detergent adhesion and increase dwell time. It also slows drying. EZ Cling is non-hazardous, sodium hypochlorite stable, and will not dilute your mix.


Understanding the elements that go into the cleaning equation provide the professional wash contactor with an enormous advantage over his or her competitors because it provides practical guidelines for determining the most appropriate bleach concentration to work safely, effectively and efficiently.

To learn more try our online Roof Washing course

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