Advanced Structural
Designs ACN 097 789 87
92 Vasey Cres CAMPBELL ACT 2612 Telephone 61612171 Facsimile 61612170 Email mal@structuraldesigns.com.au
How far apart can I space my joists if I am using particleboard
flooring?
To keep things simply for the moment let’s limit the discussion let’s
assume we are talking about residential construction loads. The choices then are usually to use say
Yellow tongue Structaflor (19mm thick) with joists at
450 centres or red tongue particleboard (22mm thick) with joists at 600
centres. The additional cost of the red
tongue is around $5.50/m2.
If joists were spanning say 4m you would require HJ240 Hybeams (“I”
shaped fabricated timber joist) at 450 c/c or HJ 246 Hybeams at 600
centres. The cost saving for the joists
is around $5/m2 so the material cost is nearly identical.
Benefits of the 600 spacing would be
- Fewer beams
to install.
- Less
nailing and gluing required for the floor and ceiling.
- Less labour
in fitting ceiling insulation.
- Fewer holes
to be cut for services.
- Fewer
obstacles for down lights.
- Fewer trees
being chopped down.
The only downside would be that some builders perceive the wider spacing
as a little more dangerous to walk on during construction. Other builders say they don’t walk on any
joists until the floor is in.
As a rule of thumb we tend to opt for 600 mm joist spacing if joists are
spanning 4m or more and 450mm spacing if they are spanning less than 4m. This having been said, if we know the builder
we ask their preference as everyone has their own perspective on issues such as
site safety.
The other issue we consider is what stud spacing we require on the lower
floor because it is preferable to have the joists and studs lining up if you
are looking to avoid the expense of double top plates etc.
As usual this is a small slice of a complex picture and we tend to treat
each case on its merits. If you need
more specific advice and reside in the Canberra ACT region give Mal Wilson a
call on 61612171.