Building A Redwood Deck
The addition of a wood deck is an easy and economical way to improve your home. Deck construction is uncomplicated and is, therefore, a manageable undertaking for someone who doesn’t have a great deal of construction experience.
Most single level decks consist of the same components. However, each element will vary in size and quantity depending on the shape and size of the deck. Nonetheless, the types of materials used should remain consistent. For example: the piers should be made of concrete, the frame that supports the decking should be a pressure treated material and the deck boards themselves should be cedar, redwood or some other weather resistant lumber. We do not suggest painting deck boards and we also feel uncomfortable about suggesting the use of pressure treated material for any surface that will be walked on bare foot or that can be chewed by a youngster. Paint on a deck can be a mess if it doesn’t hold up. And, unfinished pressure treated material can be hazardous to a busy toddler with an appetite for eating the world. The chemical used in the pressure treating process is a pesticide. The underside of the deck will be stronger and more weather resistant if pressure treated material is used. Normally, this area is inaccessible to small children and their hunger for new tastes.
As with all good construction, the quality of a wood deck begins with the integrity of its’ concrete foundation. Although there are only a few basic types of foundations it is always a good idea to check with an engineer just to make sure the type you intend to use is adequate. Deck foundations normally consist of a combination of pre-cast concrete pier caps supported by poured-in-place concrete footers. The footer is simply a hole in the ground filled with concrete. The size and depth of the footer depends primarily on prevailing soil conditions. Where footer dimensions will vary, the pre-cast pier cap is a standard hardware item that is readily available. For best results carefully level each pier cap before the supporting footer concrete dries.
The frame can consist of wood beams supported by piers or beams and piers with a layer of joist on top. Beams are used alone when there isn’t enough room for two layers of framing. And beams are more cost effective when used without joist. Naturally, less material, less expense. Where floor joist are used at 16- or 24-inch centers beams can be stretched out to as much as 4-feet apart. We like the girder joist combination because it is stronger, but if you have a limited budget, then go for beams only. Keep in mind that the deck frame will be exposed to the elements and should be assembled with fasteners that are coated to prevent rust and corrosion.
As we noted earlier, we feel good about using pressure treated material for the framing parts. But, we prefer to use either Cedar or Redwood for naturally finished surfaces such as the decking and rails. However, pressure treated Southern Yellow Pine is OK if a painted finish is desired. Cedar and Redwood contain natural resins that resist insect attack and moisture damage and provide a luxurious natural wood look. When lightly oiled, these materials become even more weather resistant. If you like the Knotty Pine look you may want to consider Alaskan Yellow Cedar. Yellow Cedar looks like Knotty Pine, but is weather resistant where Pine is not. By the way, if Redwood is the chosen material consider using Construction Heart Redwood. It’s desirability stems from the fact that is moderately priced and reasonably knot free.
Here is an important tip that will help to reduce wood rot. Remember: wood rots when it remains wet for long periods of time and wood-to-wood connections have a tendency to retain water – wet wood equals rotten wood. Eliminate wood-to-wood connections by insulating them with strips of plastic. You can use old plastic trash bags. Siding paper or roofing felt also works. Staple a strip of the plastic or felt to the top edge of each floor joist so that the strip insulates the joist from the decking. By preventing the two wood surfaces from coming into direct contact water retention – and accompanying wood rot – is minimized. Insulating material is not required when hidden deck fasteners are used. Hidden fasteners not only provide a clean look they also provide an space between the joist and the decking insuring a connection that will dry almost as quickly as fully exposed surfaces.
It may be interesting to note that when decking is installed at other than right angles to the joist there can be as much as 20% waste. We don’t recommend against installing decking at an angle, but we do want you to know that there is some additional labor and material cost involved.
Handrails are required for safety when a deck is 30” (or more) above ground. Conversely, handrails also can be used to divide (and define) areas within a deck or to separate the deck from other areas of the landscape — regardless of ground clearance. In any event, it is important to check the current building code when preparing to build handrails. The building code defines how much weight a handrail must resist to qualify as a safe rail. The code also specifies the maximum space allowed between rail surfaces (horizontal or vertical). Remember that toddler we were talking about earlier? Well, using the proper spacing will prevent little heads from getting stuck between the spindles.
If you need help constructing a deck there are a couple of great resources that offer inexpensive planning tools. The California Redwood Association has created a deck building kit that includes everything needed to design a deck including instructions, deck and furniture templates, graph paper, and even construction details drawn to scale. Contact the CRA by dialing (415) 382-0662. Computer buffs definitely will want to look into a 3D deck software called “Build Your Own Deck” from Books That Work in Palo Alto, California at (650) 326-4280. A novice can design a deck with this software in about 20 minutes. Spending another 10 minutes with the program generates printouts of construction drawings and a complete material list – unbelievable!