Limewash and whitewash are two techniques used to give brick a light, matte finish, but they differ in composition, application, and permanence. The best choice depends on your aesthetic goals and the specific surface.

Composition

• Limewash: A natural and environmentally friendly option made from limestone, water, and sometimes pigments. It is breathable and soaks into porous surfaces like brick.

• Whitewash: Traditionally made from lime, water, chalk, and binders, but a similar look can be achieved with watered-down white paint. It is paint-based and sits on top of the surface.

Appearance and Finish

• Limewash: Provides a natural, textured appearance that allows the brick's character to show through. It offers a more traditional finish.

• Whitewash: Creates a softer, more opaque finish, often used for a rustic or shabby-chic style.

Application and Permanence

• Limewash: Is semi-permanent and can be removed, making it a good choice if you might want to change the look in the future. It requires more skill to apply and cannot be used on previously painted brick.

• Whitewash: Is a more permanent solution. It is more forgiving to apply and can be used on painted brick. However, because it sits on the surface, it can trap moisture.

Ultimately, if you want a breathable, natural, and reversible finish for unpainted brick, limewash is a great option. If you need a more permanent, opaque coating that can be applied over painted surfaces, whitewash is the better choice. Whitewashing may also be more economical, costing approximately $1.40 to $4.20 per square foot.

Many decking oils can help slow down algae growth, but they don't completely stop it. These oils work by sealing the wood, which reduces moisture and, therefore, algae growth. Some decking oils also help protect against UV damage, but they need to be reapplied according to the manufacturer’s instructions to ensure the decking stays protected.

You don’t necessarily have to remove all the old paint before repainting your deck, but it’s best to remove as much as possible to ensure a smooth and long-lasting finish. Prioritize scraping off loose, peeling, or flaking paint, and sand down rough areas to create a smooth surface for the new paint to bond with.

DIY is possible but presents risks of uneven surfaces or improper adhesion; professionals offer expertise to ensure a lasting finish.