Add Shading for Your Patio and Deck

One of the most common and easy-to-build shading systems is a trellis-style structure that covers the top of the deck.(Artazum/Shutterstock)

Dear James: It gets too hot in the afternoon sun to use our deck, but we like being outdoors. Are there any inexpensive do-it-yourself shading projects that would help?—Kristin T.

Dear Kristin: Being outdoors on a deck on a sunny afternoon can be unbearable. You will find it worse in the early afternoon when the deck materials have already heated up. The sun is still almost overhead at that time of day, so its heat energy is very direct. Even a reasonably sized roof overhang will not help much then. Dark composite decking material will hold the heat into the evening hours.

The two most common methods to control the sun’s heat are vertical shading or a partial cover over the deck. One is called a balloon structure, which is attached directly to the deck. It is supported by the same large posts and beams that support the decking itself. This looks good because it is integrated with the deck, but it can be somewhat difficult to design and build.

Another design is a freestanding structure that surrounds the deck, but is not directly attached to it. This provides more flexibility for the design and support structure. Unfortunately, it does not provide much relief from the midday sun that is directly overhead. It is more effective for blocking the afternoon sun, which is lower in the sky.

One of the most common and easy-to-build shading systems is a trellis-style structure that covers the top of the deck. It has its own separate support structure that is built on top of the existing deck. The trellis design is not extremely heavy, so the existing deck should be able to easily support it.

Depending upon your budget and desire to see the nighttime sky, determine how much shade you want for the deck. Often, you must cover only part of the deck to achieve the level of shading you need. For example, the noon sun comes directly from the south, so you may need the cover only for the southern part of the deck for midday use.

Once you decide on the area of the deck you need to cover and shade, lay out four-inch by four-inch support post locations on the deck. Nail or screw galvanized metal post bases on the deck. Always use galvanized or stainless steel fasteners. The wood posts fit snugly into the post bases. Nail wall studs as temporary braces to the posts.

Once all the posts are placed in the post bases, attach the front horizontal beam to them. Check your local building codes for the size requirements for this front beam. It carries the majority of the weight of the top, so you may have to use double beams for adequate strength.

With the front beam secure, mark the positions of the cover joist on it. They are generally spaced at 24 inches on center, but you may want to vary this depending upon how much shading you desire. If you use tall roof joists on edge, they should provide adequate mid-afternoon shading without a cover.