Properties and Uses of Whitewash Paint

This standard includes guidance on the preparation of whitewash paint. It also includes general information on its composition, characteristics, advantages and uses. Most modern whitewash paint is made from latex paint. The most common dilution is 50/50 ….. water/paint.

Whitewash tree paint is available from Viragrow

COMPOSITION

      A water-based paint

Composed primarily of water and lime mixed to form a thin paste.

Binders are often added to improve the durability and chalking resistance of whitewash paint. These can include wheat, rye or buckwheat), starch varnish, glue, skim milk, whiting, brown sugar, vegetable oil plasticizer, casein, formaldehyde, borax or sulfate of zinc.

Fruit trees painted with whitewash paint

     Alum was sometimes added as a hardener to prevent the coating from rubbing off.

     Carbolic acid was sometimes added to create "sanitary" whitewash.

     Indigo and bluing were popular additives in counteracting the tendency of some binders to yellow.

     Whitewash can be tinted; historically, they were tinted with earth pigments, brick or stone dust; currently, lime-fast pigments are recommended.

CHARACTERISTICS

    Adheres best to rough porous surfaces.  It does not adhere well to smooth porous surfaces

    When applied to a surface, the mixture forms a thin opaque film of calcium carbonate (plaster).

ADVANTAGES

    Fairly easy to make.

    Non-yellowing (because there is no oil binder).

    Less expensive than other finishes.

    Effective in adhering to masonry surfaces.

    Considered a "sanitary" coating exhibiting disinfectant qualities (i.e. sometimes used to retard the decay of wood).

    Somewhat effective as a fire retardant and thermal insulator when applied in thick layers. (Not recommended to apply in thick coats for fruit trees)

USES

    Historically used on the exterior to reflect heat.

    Also, historically used to protect fruit tree trunks from frost and insects.

When properly mixed and applied, new growth has no trouble getting through a thin layer of whitewash

MIXES

NOTE:  This mix has good adhesion and chalk resistance.  It can also stand covered for several days before using.

    Make the lime paste by soaking 50 lbs. of hydrated lime in 6 gallons clean water

                                                   - OR -

    Slake 25 lbs. of quicklime in 10 gallons of boiling water.  Either combination will make about 8 gallons of paste.

Dissolve 15 lbs. of salt or 5 lbs. dry calcium chloride in 5 gallons of water.

Combine with lime paste and mix thoroughly.  Thin with fresh water as necessary.

GENERAL NOTES

   Before whitewashing any surface, gently wash the surface with vinegar.

   Be sure that brushes and pails are clean; be sure to strain the wash.

   Always slake the lime with boiling water and cover container with sackcloth or burlap to keep in the steam.

   Never let the lime dry up - when the lime has broken up, keep covered.

   When the lime has thinned to the right consistency, add 2 tablespoons of salt to each pail of wash.

   Add pigments if desired to achieve color.

Whitewash can be applied using sprayers or with a brush

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