A wooden deck is an attractive structure when it is well-maintained and can lasts for years under the right conditions. But wood is subject to mold and rot if it is not properly cleaned and sealed. Covering the wood deck helps protect the wood from rain, wind and other harsh elements. Numerous coverings exist that don't cost you a lot of money.
Paint, depending on the type you use, is useful for decorating your deck while also protecting it against rain. Latex paint is usually the cheapest variety, and it requires annual touchups to keep the deck looking its best. Acrylic paint is a latex variety that includes acrylic polymers that give the deck a durable finish so it doesn't require repairs as frequently. Polyurethane paint comes in two parts that require mixing before application so it bonds properly to the wood, and it also protects against moisture saturation. Generally, you need to clean the deck first before applying paint, and then lay down one coat of primer with a sprayer or roller. This helps make the paint look better while also strengthening the bond between the wood and the paint. Add two coats of paint once the primer has dried for best results. Paint cans often cost between $20 and $50 depending on the type of paint and the size of the can.
Wood stains are often oil-based, and they help prevent water from seeping into the deck because oil and water naturally repel. Stains don't require a primer first because there is a binder included in the stain that helps bond it with the wood. As a result, staining requires a little less preparation than painting does, but the deck still requires cleaning before the stain is applied for best results. The stain typically darkens the wood slightly, but some varieties contain dyes that lighten the wood if you prefer. Stains don't color the wood like paint does, however, so your coloring options are more limited. The pigments in the stain also protect the wood against UV rays from the sun. The cost of stain varies per brand, but cheaper types cost about $15 to $20 a can. Higher-end types are usually still less than $100 per can.
A sealer is another deck covering that won't break your budget. It is very effective at protecting the wood against mold and water damage, but it doesn't provide the UV protection that a paint or a stain does, so the deck may still fade over time. Sealers also dry clear so they are an effective option if you don't want to alter the natural color of the wood. Sealers need to be reapplied every few years to ensure the wood remains properly protected, and it normally gets applied with a mop. Two or three layers are usually required for optimal protection. One-gallon sealer jugs often cost $25 to $30, while the 5-gallon jugs cost between $100 and $150.
While the other options give you long-term solutions to covering a deck, a tarp is a quick short-term solution if you need to protect your deck from a severe rainfall or storm. Simply lay the tarp over the wood, and then anchor it down with bricks or weights. The more wind you expect, the more weight you need to ensure that the tarp doesn't fly away. Tarps are also useful for protecting the deck against scratching if you are moving furniture or heavy equipment across it. They are available cheaply at hardware stores and cost just several dollars in most stores that carry them.