3. EAVES FINISHES
There are a number of ways to frame and
finish eaves.
Types include simple boxed level eaves, lined
on-the-rake eaves, eaves lined on top of rafters
or combinations of these.
The level framing members, running between
the wall and fascia, are referred to as soffit
bearers or eaves sprockets.
They are spaced at 450 to 600 mm centres to
provide fixing for the eaves soffit lining, which
may be timber boarding or more commonly 4.5
mm thick fibre cement sheeting joined with a
PVC
7. Eaves soffit clearance
Where timber eaves framing passes over face
brick walls, as in brick veneer construction, an
allowance for frame shrinkage must be
provided.
If no clearance is allowed, the top course/s of
brickwork may be cracked or even dislodged
when the timber shrinks causing the eaves
framing to drop, which will allow the roof load
to bear directly onto the brickwork.
8. Eaves soffit clearance
When unseasoned, or partly seasoned, timber is used
it will continue to dry out causing a reduction in its
section size.
Timber shrinks in width, thickness and to a much lesser
extent, its length. Unseasoned timber with a width of
more than 175 mm will shrink excessively, i.e. up to 10
mm for every additional 25 mm of width in some cases.
This shrinkage usually occurs in the width of bearers,
joists, lintels and in the thickness of the top and bottom
plates. (Stud length is relatively unaffected)
Therefore, a clearance of 12 mm minimum is to be
allowed between the underside of the eaves soffit
bearer and the top of the brickwork.
9. Eaves soffit clearance
Note: No clearance is required for cavity-
brick construction or where timber frame
construction is used on its own or when
the timber framing is fully
10. Eaves soffit clearance
Material shrinkage
causes frame to
drop
End of soffit 12 mm min to allow
Result of no bearer drops for shrinkage of
clearance. with frame Brick veneer framing
Top course
tilts under
load
