STEP 4
- Locate and Dig Holes
Locate and dig
holes for footings. In normal soil the holes should be a
minimum of 24 to 36 inches deep, although the actual depth
will depend on the height of the column and the depth of the
frost line. Posts should go deeper than the frost line to
avoid heaving during freeze and thaw cycles. Again, this is
usually specified by code when the deck is attached to the
house.
If you have many
holes to dig and/or have difficult soil to dig in, you
should rent a power posthole digger. These can be operated
by one person, and certainly make the digging go MUCH
faster. Typically to rent one will cost about $50 for a day.
You can use pressure treated wood in the ground for your
footings as follows. Fill the bottom of the hole with 6
inches of gravel and place a wood footer plate (2" x 6", or
2" x 8" cut off) on top of the gravel. Upright posts can
then be positioned on this base (Fig. 3). Fill the posthole
with alternating layers of 4 to 5 inched of gravel and
earth. Tamp each layer until the hole is filled and post is
plumb and solid. If concrete collars are used, taper the
tops downward and away from the post for drainage. Posts can
also be set in concrete. Or my preferred method, uses a
cement footing to just above the ground level. Fill the post
hole completely with cement and use a section of "sono tube"
(a heavy cardboard tube, 8 inches in diameter) to finish off
the hole at ground level. Make sure you have already
purchased the hardware to attach the posts to the cement so
you can set the bolts in the cement while it is wet.
When setting the posts directly in the holes, make sure they
are plumb and in alignment with one another. Use a
carpenter's level to check for vertical alignment (Fig. 4).
One advantage of
using the cement footings and the wood attached to them
above ground, is the leveling and exact location can be set
later, when the beams are positioned. It allows for some
adjusting later (a little, but that is all you are usually
looking for.)
STEP 5
- Secure Deck Beams
Secure beams
to posts. Using a string and level, find the desired
deck floor height on the posts. Or extend a long
straight 2 by 4 from the ledger board to the posts and
placing a level on the board, determine the post height.
By subtracting the thickness of the joist (use the
actual dimension not the nominal one), you will have
determined the correct height for securing the top of
the beam to the post. Carefully mark all 4 sides of the
posts. Beams can rest on top of the post, or be fastened
to the side. You may cut all posts except those serving
as railing supports at this time. Fasten the beam to the
post, keeping post and beam flush. Or set the beam atop
the post nailing it down to the post.
STEP 6
- Prepare Deck Joists
Attach joists.
Joists are attached to the house with joist hangers
and/or supported by a ledger board. Joists are placed on
16" or 24" centers, and attached to the beams and ribbon
joist. Joists can be attached to the beams using joist
hangers, or rest on the beam. If the joists are to
extend over a beam, do not extend them more than 1/3 of
their length.
STEP 7
- Installing Deck Boards
Install deck
boards using hot-dipped zinc-coated 16-penny nails.
Separate
boards using a small finishing nail as a spacer or set
boards right up against each other. If pressure treated
wood came dry, a space would be necessary for some
expansion may take place when it gets wet. However, it
typically is quite wet and will always shrink. I have
found that when placed tight against each other they
will shrink leaving an adequate gap. If you leave to
large a gap while they are still wet, the gap may get
quite large .
Your deck surface is an important part of your project,
and the most visible. Make it simple with the boards set
to end on the joists. If you could not get decking long
enough to span your deck, stagger the butt end joints so
they do not all end along the same joist.
You can trim
your deck after nailing to assure a straight line (see
Fig. 5). Do not allow an overhang exceeding 1 ½". For a
more finished appearance, cut boards flush to the joist
and add a fascia board.
If a board is
slightly humped, install it with the bark side up when
possible to minimize cupping. The weight of people and
objects on the deck, and of the board itself, will tend
to flatten it. A curved board can also be used; use a
board to pry it to the desired position and nail
securely.
STEP 8
- Installing Deck Posts
Install posts for railing. These can be a continuation
of the posts which support the deck, or railing posts
may be bolted to the outside joist or joist extensions.
Notice in Fig.
6 how the main posts continue up from the actual deck
floor level and by doing so provide a good sturdy post.
Intermittent posts or spacer posts can by used between
the main support posts. The top railing member can be
easily nailed to the side of the main posts at desired
height. Posts can then be cut off. Spacer post height
can be determined and added for additional support and
appearance. Railing cap of suitable size can now be
added as well as additional rails. More railing ideas
are illustrated below.
The safety
and beauty of your deck are enhanced by its railings.
They can be plain or very elaborate, offering as much
opportunity for individual preference as a fence.
Benches can be
integrated into the railing on one or all sides. Bench
seats should be at least 15" wide and 15" to 18" above
the deck floor.
Privacy
screens can enhance the beauty of your deck, as well as
offering you privacy. They can also be used effectively
under an elevated deck to create a storage facility or
hide an unsightly hillside.
-
STEP 9
- Construct Deck Steps
Construct steps. Measure the vertical rise and decide
upon the best riser size for each step. This will
determine the number of steps needed. The adjacent table
shows some recommended ratios of tread length and riser
height. Multiply the number of steps by the tread length
to find the overall run of the stairs.
Using 2 x 4 or
2 x 6 boards for treads will reduce cupping problems
common with wider boards.
It is also
possible to purchase precut steps at certain
lumberyards. A call ahead might eliminate some of the
more difficult angle cutting you need to do.
Mark
off the deck area using string and "batter-boards" making
sure that it is square. Batter-boards are deck boards hammered in
to the ground just outside the corners of where the deck
will be. <<See Fig 1. The string will help you
visualize the size and appearance of the finished deck and
will also serve as a guide for excavation and post
placement. But trust me, it will always look smaller this
way than when it is done. 
A ledger / header board is the next step if you are attaching
your deck to an existing structure. 
