What Kind of Bleach Is Used on Fences?

Oxalic Acid

• You can find wood bleach solutions in home improvement stores and hardware stores. The labels of such products may read "Wood Bleach" or "Oxalic Acid." Oxalic acid is the primary ingredient in many wood bleach products, and it works by reacting with the natural acids in the woods, such as tannic acid. The reaction results in the removal stains that have formed as a result of iron and moisture. Oxalic acid also reduces the graying effects of time, making wood fencing appear newer than it actually is.

Two-Part Wood Bleaches

• When shopping for a wood bleach solution, you may find some products that label themselves as "Two-Part Wood Bleach." These solutions contain a mixture of sodium hydroxide and strong hydrogen peroxide, which react with one another to create an oxidizing effect. These two-part bleaches do little to remove stains, but they should serve as your first choice if you seek to remove the natural color of wood. For stain removal and restoration, stick with oxalic acid solutions.

Chlorine Bleach

• Chlorine bleach is not marketed as a wood bleach specifically, but still has useful applications on fencing. The oxidizing effect of chlorine bleach will specifically lighten dyes and paints on a fence without altering the natural color of the wood itself. Chlorine bleach is very powerful, so always dilute it heavily with water before applying it to a wood surface. Also wear rubber gloves to protect your skin from the corrosive effects of the bleach.

Applying Wood Bleach

• After you mix or dilute your wood bleach solution according to the manufacturer's instructions, apply the solution to a soft, clean sponge and begin scrubbing the wood surface. Keep the fence as evenly wet as possible to minimize streaks, and then immediately rinse with water. Wait for the fence to dry and then examine the color to determine if you need to apply a second coat of bleach.