In the past, many decks were built with 4×4 support posts (also called structural posts). But these can bow seriously, even if a deck is only 3 feet off the ground. For that reason, we strongly recommend that you use 6x6s instead, even if your building department does not demand them. And if a deck […]
The footings of your deck are exactly what they sound like – the feet of the deck. They’re the concrete foundations that support your deck. In order for posts to properly resist varying degrees of weight, posts must rest on and be anchored to concrete footings. It’s important to note that patios and pre-cast concrete piers do not qualify as proper footings for deck construction. To anchor posts to concrete footings, you need to use a post base connector. Whether you’re using natural, decay-resistant or preservative-treated wood, it’s recommended that posts be elevated off the concrete by 1 inch to help prevent decay at the end of the post due to moisture.
Using a notched post and beam connection will lock the beam in place, secure it from rotating and resist wind uplift. Notching a post does not weaken the structural integrity of the wood support post because the load for the deck is transferred down through the post to the footings. The upright notched section of the post acts stabilizes the beam. Most deck builders use a reciprocating saw to cut an L shaped seat in the top of the post large enough to hold the beam. Another building method to consider if you don’t have a reciprocating saw involves using circular saw to score the top of the post to remove the weakened sections with a chisel. A 2-2×10 beam will require a notch 3” wide by 9-1/4 inches tall. To hold the beam in place you will then need to predrill and run two ½” threaded carriage bolts through the beam and the top of the notch.
Round steel structural columns with base plates welded to the top and bottom are another option. The most cost effective steel post is 4.5” diameter with 1/8” thick walls. Many of these are part of an assembly for a decorative columns. Steel is rarely used in residential deck construction because it is expensive, not readily available and more complicated to install. If you do choose to use steel be sure to check it out with your building inspections department and follow the manufacturer’s installation instructions.
Save This type of footing basically continues the pier vertically to the deck frame eliminating the need for any wood support posts. We recommend that you do not exceed 36” in height above grade. If properly installed this would definitely be the most durable choice, however it is rarely built because it involves using more […]
It if often practical to use a common post and footing to support two or more beams in a deck design. This usually happens in multilevel decks where a lower deck intersects with an upper deck along a line of posts and footings. Stair landings that wrap around the frame of a deck often take advantage of sharing a corner post.
A girder, cantilevered or drop beam is a structural member positioned below the joists to support the weight of the frame. Cantilevered beams are stronger than flush style beams because they rely on the strength properties of the wood rather than the individual mechanical and fastener connections.
Save While all deck beams are designed to carry weight, there are different ways to install them. The average deck built at a home normally sports two different types of beams: Drop beam Flush beam The drop beam is one which sits below the plane of the floor joists. The flush beam is one that’s […]
The span of a beam is dependent on a few variables: The grade and species of lumber, size of lumber and the load it carries. Fewer posts on upper-level decks are typically more desirable to the occupants and this drives the use of larger framing materials for longer spans. Beam span maximums are based on a maximum anticipated live load as well as other factors. Building codes for residential decks only require 40 psf in some areas, but check your local requirements to make sure you are aware of any additional local guidelines. In addition, many residents prefer the fell of a deck that is designed for higher loads. The longer the joist, the more area of deck the joist supports, and thus the beam supports more area as well.
Save Bringing your favorite people together to enjoy a beautiful summer day on your deck is a great way to unwind and relax. And while it’s important to have a deck that’s aesthetically pleasing to you, you first have to make sure it’s structurally sound. That includes knowing the difference between a joist and a […]