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Each beam will be comprised of: (A) a double beam -
two 2x6’s together; (B) a 2x4 bottom plate that will
hide the seam of the two 2x6 beams; (C) two “legs”
(one on each end), which are 1x4’s that will hold the
beam to the posts; and (D) two 45 degree braces.
Some pergolas may have larger members due to
customized or increased strength required, but the
basic beam assembly is the same.
1.
Install the Beams
: Though there is no set order, it
usually works best to install the shorter beams first.
Allowing a better feel for how they are done using
lighter beams. Lift the beam into place until the top of
the beam is flush with the top of the posts and
centered. Secure each beam with five 2½” screws –
three on the leg, one below the brace and two above.
(As shown to the right) There is also one screw on an
angle on both sides of the beam driven into the posts.
Do this on all connections to the posts.
2.
Do the Same for Longer Beams:
Note: If the pergola is over 16’ long, there will
be a center post, making two sets of beams for each side of the pergola. Installing
the beams is the same no matter how long or how many beams there are.
3.
Install the Top Plate
: The top plate is a piece of 2” x 8” wood that is precut to fit
on top of the beams. Rest all 4 pieces on top of the beams. Arrange them so that
they fit tight at the corners. (NOTE: On larger pergolas, there may be more than 4
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top plates as some of the sides will need more than one board.) Two of the top
plates have marks for positioning the runners – these are usually set on the longest
dimension since runners span the short dimension. On square pergolas, the parts
are interchangeable, but the top plates with the markings need to be on opposing
sides. Be sure that the markings are facing up as shown below.
4.
Join the Top Plate Pieces:
The top plate
pieces must be joined together
before
attaching them to the top of the posts or to the
beam. Place 3 ½” screws on an angle at the
corners as shown. There are no predrilled
holes. Since the screw is close to the end,
predrill a 1/8” hole.
5.
Attach Top Plates:
Position the assembled
top plates so that the seams in the corners are
centered across the corner posts. The top plate
will overhang the beams by about ½” - 1" on
the inside. Before attaching to the posts and to the top of the beam with 2 ½"
screws, make sure that the overhangs are the
same along the entire perimeter. Attach with
two screws at an angled cut into the top of the
wood posts and then along the beam approx.
every 24”.
Note:
If the top plates are more than one
piece, attach at the place where they join with
four screws – two on either side of the seam.
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top plates as some of the sides will need more than one board.) Two of the top
plates have marks for positioning the runners – these are usually set on the longest
dimension since runners span the short dimension. On square pergolas, the parts
are interchangeable, but the top plates with the markings need to be on opposing
sides. Be sure that the markings are facing up as shown below.
4.
Join the Top Plate Pieces:
The top plate
pieces must be joined together
before
attaching them to the top of the posts or to the
beam. Place 3 ½” screws on an angle at the
corners as shown. There are no predrilled
holes. Since the screw is close to the end,
predrill a 1/8” hole.
5.
Attach Top Plates:
Position the assembled
top plates so that the seams in the corners are
centered across the corner posts. The top plate
will overhang the beams by about ½” - 1" on
the inside. Before attaching to the posts and to the top of the beam with 2 ½"
screws, make sure that the overhangs are the
same along the entire perimeter. Attach with
two screws at an angled cut into the top of the
wood posts and then along the beam approx.
every 24”.
Note:
If the top plates are more than one
piece, attach at the place where they join with
four screws – two on either side of the seam.