How to Weatherproof Indoor Furniture for Outside Use

Furnishing an outdoor living space with “outdoor” furniture can get expensive. Often, it’s simply easier and more resourceful to upgrade a piece of “indoor” furniture for outdoor use.

Hardwoods and softwoods alike can make the transition to being outdoor furnishings with the right protective sealants. For example, if you have old kitchen cabinets, you might find that you can use them to enhance storage on an exposed porch or add functionality to an outdoor kitchen. Extra coffee table? Put it on the patio to round out your morning coffee spot. Even conventionally “indoor” sofas, sideboards and accessories can be sealed and safely repurposed as outdoor features.

Which Sealant Will Work Best?

Sealing your furniture will help protect it from moisture penetration that leads to discoloration, cracks and even mold. There are a wide variety of weatherproof sealants that you can apply to indoor furnishings that will help them endure the outdoor elements. The most common options include:

• teak oil
• Danish oil
• tung oil
• spar urethane
• spar varnish
• exterior latex paint
• chalk paint

Rules to Follow When Using Sealant

1. Apply weatherproofing when the temperatures are moderate. Between 60 and 80 degrees is ideal.
2. Avoid shaking cans of sealants. Shaking the liquid can create bubbles that transfer to your furniture.
3. Proactively avoid damage by shielding your furnishings from harsh weather conditions. Move your wood furniture indoors over the winter and cover it on rainy days.
4. You will have the best results with routine resealing. Plan to add another coat of weatherproofing every year.

How to Waterproof Furniture With Wood Oils

Massaging a generous layer of oil into the surface of your wood furniture enhances its waterproofing abilities. Wood oil can only be applied to wood furniture that has not already been sealed. It can yellow over time so it is best used for darker wood grains.

Types of Wood Oil

• Teak oil is a common outdoor wood oil used specifically for hardwoods like teak, rosewood and mahogany. It penetrates deep and creates a durable, UV-resistant finish.
• Danish oil is a water-resistant blend of resins and natural oils. It is toy- and food-safe and dries to a hard finish. High-quality products offer UV filters.
• Tung oil dries quickly and is also naturally non-toxic. It offers a waterproof but flexible finish that allows the wood to contract and expand with fluctuations in temperature and humidity. It does not naturally offer UV protection, but UV absorbers are often added to exterior tung oil products.

How to Apply Wood Oil

1. Prep the furniture surface with 400-grit sandpaper. Sanding helps open the grain.
2. Wipe the surface with a tacky cloth to remove any dust created when sanding.
3. Stir the oil in the can. Do not shake the product.
4. Use an oil-dampened cloth or a paintbrush to apply the oil directly to the wood. It will begin to absorb before your eyes.
5. Use a dry cloth to wipe up any pooled oil. Massage the oil in and examine for areas that did not receive a thorough coat.
6. Place the oily rags in a bucket filled with water and leave it outdoors. Oily rags can spark fires as they dry.
7. Allow the furniture to dry overnight.
8. If additional coats are desired, use a piece of 400-grit sandpaper to lightly roughen the topcoat. Once again, use tacky cloths to eliminate any dust before adding another layer of oil.
9. Apply an additional coat of wood oil. Allow it to dry overnight. Repeat as needed.

How to Waterproof Furniture Using Heavier Sealants

The process of weatherproofing wooden furniture with sealants isn’t much different than applying wood oil, but the products themselves offer different benefits. These sealants can be used to update an existing sealant on the furniture so it can endure outdoor weather. Learn about the differences between polyurethane, varnish and paint as common furniture treatments:

Types of Heavy Sealants

• Spar urethane, an outdoor-friendly polyurethane, contains UV absorbers that are ideal for maintaining an outdoor wood finish. It is available as both an oil-based and water-based product and also comes in a range of finishes from satin to gloss. Spar urethane allows the wood to expand and contract with changing temperatures. It dries in just a few hours, but you should plan to apply several coats for the best effect.
• Spar varnish is a great topcoat for outdoor and raw wood projects, especially if they are going to be in contact with water and in full sunlight. It’s marine-rated, so you can trust that it will help your indoor wood furniture hold up to unexpected outdoor weather.
• Exterior latex paint is a great option for wooden furniture that needs a total makeover. Sand and prime the wood first for best results.
• Chalk paint is another great outdoor solution for outdoor furniture, but it must be covered by a polyacrylic lacquer to prevent fading in the sunlight.

How to Apply Sealant

1. Prep the wood surface with 400-grit sandpaper. Sanding helps open the grain.
2. Wipe the surface with a tacky cloth to remove any dust created when sanding.
3. Stir the sealant. Avoid adding air pockets to any of these products, too.
4. Use terry cloth, cheesecloth, a paint roller or a paintbrush to apply the sealant directly to the wood. Brushes and rollers are useful for applying spar urethane or varnish on flat surfaces, but you may find it easier to prevent drips by using cloths on detailed areas or vertical sections of your furniture.
5. If you’re using an oil-based product, put the oily rags in a bucket filled with water and leave it outdoors. Soaking oily rags can prevent fires.
6. Allow the furniture to dry according to the product directions. Some products cure in two hours, while others may need a full 24 hours to set.
7. If additional coats are desired, use a piece of 400-grit sandpaper to lightly roughen the topcoat. Use tacky cloths to wipe down the furniture once it is sanded.
8. Apply an additional coat and repeat as needed.

Don’t Forget About the Fabric

Be sure to treat cushions and fabrics, too. Indoor upholstery can easily fade in the sun and cushions certainly won’t be water-resistant without extra treatment. Give all fabric a healthy dose of Scotchguard so that it can repel moisture and damaging UV rays.

Pro tip: You can extend the life of all outdoor fabrics by treating them for additional water repellency (even the specialty-fabric sun umbrella over your patio table). An extra layer of protectant will help those fabrics stay vibrant longer, too.