Transcript Unit 44 — Ceiling Framing

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Unit 44
Ceiling Framing
Ceiling Joists • Laying Out Ceiling
Frames • Constructing Ceiling
Frames • Attic Scuttles • Constructing
Flat Roof Ceilings
Unit 44 — Ceiling Framing
A ceiling frame ties together the exterior walls and
resists the outward pressure of roof rafters.
Unit 44 — Ceiling Framing
Ceiling joist size is
based on the
amount of weight
the joist must carry
and the joist span.
For example, No. 1
2 × 6 Douglas fir
joists spaced 24″
OC can span up to
14′-5″.
Unit 44 — Ceiling Framing
When ceiling joists
butt over a partition,
an 18 ga  18 long
metal strap can be
used to tie the joists
together.
Unit 44 — Ceiling Framing
Whenever possible,
ceiling joists should
be nailed to rafters.
Unit 44 — Ceiling Framing
When ceiling joists do not run parallel to the roof rafters,
2 × 4s can be used as a tie between exterior walls.
Unit 44 — Ceiling Framing
Stub joists may
be required
where rafters do
not run parallel to
ceiling joists.
Unit 44 — Ceiling Framing
A 1 × 4 ribband nailed at the center of the joist spans
prevents twisting and bowing of the joists.
Unit 44 — Ceiling Framing
A strongback provides central
support for the joist span.
Unit 44 — Ceiling Framing
When studs and ceiling joists are spaced 16 OC, the
joists rest directly over the studs. When studs are
spaced 16 OC and ceiling joists are spaced 24 OC,
every other joist will align with the studs below.
Unit 44 — Ceiling Framing
A ceiling frame is
constructed over walls that
have been straightened and
properly braced. In this
example, joists lap over an
interior bearing partition.
Unit 44 — Ceiling Framing
A ledger board is nailed
against the wall to
provide a nailing surface
for lower ceiling joists.
Unit 44 — Ceiling Framing
Backing is nailed to
the top plates to
provide a nailing
surface for the edges
of the finish ceiling
material. Backing may
be 2 × 6s or 2 × 8s.
Unit 44 — Ceiling Framing
Backing is
sometimes nailed
on top of bearing
partitions.
Unit 44 — Ceiling Framing
Blocks and backing are
installed between joists to
secure tops of walls running
parallel to ceiling joists.
Unit 44 — Ceiling Framing
For flat roofs, rafters
serve as a base for
the roof and as ceiling
joists. Since joists for
a flat roof must
support the combined
load of the ceiling and
roof materials, 2 ×
10s or larger framing
members are used.
Unit 44 — Ceiling Framing
A flat roof must
have a small
amount of pitch
for proper water
drainage.
Unit 44 — Ceiling Framing
Parapets can be
framed over top
plates.
Unit 44 — Ceiling Framing
Parapets can
be framed into
exterior walls.