Wisconsin Woods Woodworking

April 2009

New Plans Added!
	We would Like to welcome the folks from the WOOD Store and the Woodworker Book Shop. We are pleased to be featuring plans and books from them in our plans section and welcome them as contributors to our web site. Please check out some of the unique offerings we have selected from them on our plans pages, or use the links shown here to view all of their great plans and products!
This Months Feature - Deck Framing Simplified
	With Spring right around the corner here in Wisconsin, we are starting to plan for this years outdoor projects. One area that many of you have expressed confusion over is how to properly size the structure under your decks. In most areas this is a project that requires a building permit, and is subject to local building codes, so check with your local zoning department before proceeding. Your local codes may be more stringent than the standard tables I am using, but the process will be similar. If you are unsure you may want to engage an architect or engineer to help with the planning. If you are in a colder climate like here in Wisconsin you will most likely require frost footings for your posts as well. You will also have varying railing and esthetic requirements as well, so obtaining several books on design construction are recommended and we have links to several resources featured. The goal today though is to help you understand the often confusing planning around your structural elements - so lets get started.
	We will be planning a 16 foot wide by 20 foot long deck topped with 5/4 X 6 cedar decking. One end of the deck will be attached to the house foundation with the remainder supported by beams and joists. We hope to use 2 X 8's for the joists and beams. As you will see during our planning that these design considerations may change as the planning progresses. Our deck will be 36 inches above ground and we anticipate using douglas fir 4 X 4 posts. We will begin the design process from the top down. Using our 5/4 X 6 cedar we can see that our joist spacing must be 12" on center. If we used clear cedar we could increase that to 16" on center spacing which might be necessary if we elected to lay our decking on a diagonal. Because clear cedar is fairly standard here for decking let's use that with 16" spacing.	From Taunton Press Download this video today!
	Our next design consideration is our joist size and the length of the span between beams. We know we are using 16" joist spacing and our total span is 20 feet. We also want to cantilever the end of the deck over the beam which as a rule of thumb can be up to 1/3 the joist span. So let's go 2 feet with the cantilever so our maximum span is now 18 feet. With the ledger end supported by the house foundation if we place one more beam at the half way point between the house and the outside beam the span is now 9 feet. Looking at our table to the left we see that with 16" joist spacing and 2 X 8 douglas fir we are well within the maximum span for our 2 X 8's which is 12' 10". We actually could use 2 X 6's but we are very close to the maximum span of 9'3" so in the interest of a nice solid deck we will stick with 2 X 8's.
	Now that we have the decking and joist layout, and we know we will need 2 sets of beams 9 feet apart, the last area we need to focus on is the beam and post size and post spacing. From the chart to the left, with our 9 foot Joist span we need our posts no more than 8 ft. apart using a 4 X 8 or doubled up 2 X 8 beam. With our 16 foot width if we use 3 posts per beam spaced 6 feet apart and 9 feet between beams gives us 54 sq ft. of load area, and because our height is less than 6 feet we can use 4 X 4 posts. This should give us a strong, stable deck structure. Alternately if we were making the deck taller such as a second floor walk out deck, we could have used 4 X 12 beams with 2 - 6 X 6 posts spaced 12 feet apart to allow more open space under the deck which would support a deck over 6 feet high and 124 sq ft. per post.
See all the deck plans from our affiliate WOOD Store!	That is the basics behind designing and sizing your deck structure. Remember though that your local codes may have more or less stringent requirements so be sure to check with your local building inspectors before beginning. There are a host of different materials and deck designs you can consider to complete your deck! Check out the links we have provided for different plans and idea books from our affiliates!
	NEW REVIEWS! Check out our new review of the Wixley digital Angle gauge!