Establish the perimeter
The first joists that are installed are the rim
joists. These are the two end joists and they attach
to the ends of the ledger board and extend across
Nail one rim joist to the end of the ledger board
being sure the crown is up. Position the free end
of the rim joist flush with the end of the beam.
Repeat this for the other rim joist.
Measure and cut the header joist to length (same
length as the beam) and nail it to the free end of
the rim joists. You should have four boards in place
now, the ledger, 2 rim joists and the header joists.
Square off the framing by measuring the diagonal
corners. When the measurement is the same the framing
is square. Nail the rim joists to the beam using
three 3-1/2" framing nails per rim joist.
Lay out the joist spacing
On the header joist and the ledger board measure
out joists at 16" on center. Square off your
marks using a framing square.
The ledger board will need to have joist hangers
installed to carry the joists. Use a short scrap
of joist material to act as a guide block for the
joist hanger. Position the scrap on your marks and
mount the joist hanger being sure to use hanger nails.
Visually inspect each joist to establish the crown
of the board. Mark the direction of the crown on
the joist with a pencil. Now measure the length of
the joists and cut. Remember the length of the joists
will be 1-1/2" shorter then the rim joists.
Place a joist into each joist hanger on the ledger
board. Make sure the top of the joist is flush with
the top of the ledger and that the joist fits tight
against the ledger. Secure the joist into the hanger
using hanger nails. The building inspector will inspect
to make sure the hangers are completely nailed off.
When all the joists are secured in the hanger you
can nail through the header joist securing the free
end of all the joists. A general rule for nailing
is to use one 3-1/3" framing nail for every
2" of joist depth. ie: A 2x10 joist will require
Secure the joists to the beam by toe-nailing through
the sides with 3-1/2" framing nails.
Finally the joists need a row of center blocking
along their mid span to ad strength to the floor.
The maximum allowable span without blocking varies
from area to area so check with your building department.
As a general rule any span over about 7'-6" will
need center blocking.
Joists 16" on center will require blocking
that is 14-1/2" long. Simply snap a chalk line
across the mid span of the joists and add the blocking
into each space between the joists. Nail through
the joists into the blocking.
With this step complete it is time for decking.
article in the series - Laying the Decking »»