Common sense tells you that large floor joists can carry more load and spacing joists closer together also increases the load bearing capacity of a floor.
Timber frame floor joist spacing.
But larger is not always better when builders are constructing a home or adding a room addition.
Make sure your joists are spaced correctly deck joist spacing should never exceed 16 on center with the exception of max deck boards which allow for maximum 24 on center.
White cloud wrote the maru system i mention does not lay the timber frame joists on edge but on the flat in many cases the joist are square as that is part of the design.
How are framed floors installed.
Usually 400 450 or 600mm but any value can be used up to 610mm max.
This a rough guideline.
If you simply flip the joists on edge without adjust their spacing or the flooring above it may be weaker.
Some newer homes have manufactured i beam shaped joists.
Beam and joist floor frames can be constructed on site or off site and transported in depending on your foundation.
Suitable for uk building regulation approval.
Not the best method to design a floor system.
When you do it the other way around your spacing of the floor joist must be altered to fit the size joist you need to use.
Floor joists are typically 2 by 8s 2 by 10s or 2 by 12s.
This is the distance between joist centres.
The following table gives details of allowable spans and spacing between joists for the most common timber sizes used in floor construction.
Most decks use 16 on center spacing for joists.
1 2 timber strength class and joist size.
However when running spf 2 6 floor joists into the floor joist calculator referenced above you get a maximum span of 9 feet 8 inches with a minimum bearing length of 3 inches at each end on 12 centers.
Probably not but it is possible.
Those that support butt joined flooring need to be 45 or 50mm thick to reduce splitting.
Most decking is not strong enough to support longer spans than 16.
All the figures are based on normal domestic floor loadings where the floor construction is typically 18 25mm floor boards sheets with up to 12 5mm thick plasterboard and skim underneath.
Leave the crowned joist and apply sister joists by sandwiching the board with two new joists.
Joist spacing for composite decking.
A floor s framework is made up mostly of wooden joists that run parallel to one another at regular intervals.
Joists that sit below end matched joints must be at least 35mm thick.
Structural calculations for timber joists timber beams glulam beams flitch beams using the latest design codes.
Here you have limited the spacing as well.
The extra two inches of vertical distance when a floor is framed with 2 x 10 joists rather than 2 x 12s can be quite important for example.
