Even if the house plans provided an attic access, this does not mean the
trusses were designed to take an additional load above the ceiling. Its
implied by the attic access provided by the builder, but that doesn't mean
its true.

The chords tie the joist to the rafters in a typically angular fashion.
These are mutually supportive of both the joist and the rafter.

Trusses are designed to provide a minimum ceiling load as is. Especially
the exclusive 2X4 type. I wouldn't trust these without the chords in place.
A long run over a bedroom, living area etc is inviting disaster for storage
purposes in the attic. You cut the chords, and its an even worse situation.

Conventionally framed roofs with ceiling joists of adequate width meant for
storage is probably the only type one can safely store your stuff in the
attic. A few truss designers will design these if the ceiling load specs
are provided by the builder, but its not seen very often.

"Ken Moiarty" wrote in message
news:BYdwe.1819374$Xk.1125184@pd7tw3no...
Background: I'm trying to modify my attic a little bit in order to store
some things up there. Currently I'm busy fastening 3/4" plyboard over the
ceiling rafters (so objects to be stored won't crash thru the drywall
ceiling). However movement/activity up there is hampered by the fact that
the roof is supported by factory produced 2x4 trusses, as these are
composed
of many cross members that switch back-and-forth at oblique angles between
the upper and lower rafter sections of each truss. It would certainly
make
my attic storage efforts easier if some of these cross-members could
somehow
be removed out of the way (that is... in such a way as to not compromise
the
structural integrity of my roof, of course).

Therefore I'm requesting feedback on the following idea: 'Sistering'
(i.e.
reinforcing with) 2x6s to the topmost rafters, followed by removal of some
of the supporting cross-members of said trusses. Not being a carpenter or
structural engineer of any kind, I'm seeking informed comments/advice from
others before going further with this.

Thanks.

Ken