Lime whitewash has fallen out of favor as a finish for brick. However, if you prefer a rustic finish, whitewash has several advantages. Unlike paint, whitewash does not peel, or require upkeep to maintain its intended appearance. Instead, it wears away slowly, creating a weathered look that many people prefer. If too much of the lime whitewash has worn away, more can be applied in the worn areas or another complete coat can be added to the wall.
Step 1: Mix the whitewash by combining 2.5 gallons of hot water and 25 pounds of lime in a 10 gallon bucket. Allow this mixture to cool for 12 hours before proceeding. While waiting for the lime mixture to cool, mix 6 pounds of salt, 3 ounces of Potash aluminum, 1 pint of unsulfered, clear molasses, and ¾ a gallon of warm water in a separate bucket.
TIP: This lime whitewash recipe creates roughly 4 gallons of whitewash. If you think that you may need more, this recipe can be doubled easily. Be sure to use a large enough bucket for stirring if you do decide to increase the amount you mix.
Step 2: Add the molasses mixture to the lime bucket. Stir thoroughly.
Step 3: Wet the brick that you intend to whitewash with a garden hose. If you have a large area to cover, wet the brick in sections, apply the whitewash, and then proceed to the next section.
Step 4: Apply the lime whitewash you created in step 2 with a stiff bristled exterior paintbrush. Avoid using a paint roller or paint sprayer for this step: the paintbrush will create the appropriate texture.
TIP: When applying whitewash, you may wish to apply the mixture more heavily on some areas. This will give the brick wall a head start on the weathering process.
Step 5: To create an even more weathered appearance, wait three hours and then rinse off some of the whitewash from the brick. Do this in varying sections to create the look you would like. Of course, this step is completely optional: if you are happy with the appearance of your brick wall after applying the whitewash skip this step.