The Medway Handyman wrote:
Hi

I've been asked to build a 15' x 12' wooden deck to hold a hot tub. Most of
the joists can rest on a small retaining wall, a concrete slab and a wall
plate fixed to the garage wall.

The tub holds 1300 + litres of water & up to 6 adults, so adding the (as yet
unknown) weight of the tub itself I could be looking at 2 tonnes here.

Would I increase the strength much by spacing the joists at 12" rather than
16" or would extra noggins be a better bet?

Cost isn't the major issue, I just want to make sure it's strong enough.


Online calculators should help. A quick look turns up
http://www.awc.org/calculators/span/...rcalcstyle.asp - it's
american so not ideal, but suggests that 2 x 10 softwood joists at 16"
centres can span 11'6" with a 2 tonne dead load. Playing about with the
options should give you a good guide.

Andrew