Welcome to installment 2 of the deck building series. Deck Design and Framing Concepts looks at the
typical framing elements used in deck construction, the value of using pressure treated wood, and
framing the understructure of the deck.
Although the concepts presented here are generally accepted guidelines, always consult your local
Materials Used for Deck Framing
Your decks understructure not only gives your deck its basic shape, but its strength as well.
Its understructure is made up of joists, posts, and beams. Selecting the best and appropriate building
materials is the basis for a long life.
Wood: Be certain to select only pressure-treated lumber. In addition,
its preferable that it should be treated with an insecticide; one that does a good job
is chromated copper arsenate (CCA).
As far as the wood itself is concerned, Douglas fir and
southern pine are good choices. For added protection, its a good idea to brush on a brush
preservative on wooden surfaces that you cut or drill.
Your plan should be to use one to two bags for each post dependant upon post depth. And its always a great idea to dig your post holes about 3 deeper than needed and pour in a layer of pea gravel.
Why? Because this will help with proper drainage away from the posts base. Rotten posts are a bad thing.
Hardware and Fasteners: Count on using framing anchors, deck screws, bolts, and nails. All should be specially coated for todays pressure treated lumber; pay a few pennies more and make it last. Purchase your deck screws with an additional resin coating.
Specifics on Attached Decks
If youre planning to build an attached deck, you will attach a 2 X 4 ledger
board to the house;
its important that it's absolutely level. A laser level is ideal for this.
The ledger supports one
side of your deck; the rest of your deck will be supported by 4 X 4 or 6 X 6
posts, depending on
the size, height, and load.
Your beams will be secured to the top of your posts and parallel to your ledger board. The total
number of beams and rows of posts that you will install is dependant on the final size of your deck
and how much weight load its expected to bear.
Other considerations must be made when a hot tub or
other items will eventually be supported by the deck. (Lumber sizes and spacing are covered in the
next article of this series.)
Your floor joists will run from your outer beam to your ledger board. Hardware include joist hangers on
your ledger board as well as post caps on your beams to lend support to your joists. A rim joist will be
attached to the open end of your joists.
Specifics on a Freestanding Deck
A freestanding deck is basically the same as an attached deck except that in place of the ledger
board, a beam and a row of posts are used. This construction method is ideal for building a shed.
Weather and Climate: Things to Think About
In locations where extended freezing periods are expected, your posts should be set at a minimum
of 8 below the frost line. At the other extreme, in locations where there is no danger of freezing,
posts may be attached to precast concrete pier blocks.
Whichever method is used, always consult local building codes.
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