Hi all, Compared to some of the amazing information I have seen here I
think this one should be a snap

I am looking to support a 8-man hot tub. The tub weighs about 1000
pounds empty and holds 530 Canadian gallons of water. So with people
plus a safety factor I figure about 8,500 lbs.

I want to support this on four adjustable points.

Here’s what I have so far….

It has a 90" X 90" footprint and I built a platform 90" square using
pressure treated 2X6 studs at 12" centers. It also has a double 2X6
plate at each end. I covered the platform with 5/4"X6"X8’
pressure treated deck boards with 1/4 inch spacing. Two screws at each
joist.

This gives me 56.25 sf to support the weight. It works out o be 150
psf…any comments so far on the platform??? I guess this would
depend on where the supporting beams were to be placed…read on.

I have four concrete blocks, each 8" X 8" X 16". When viewed from top
you see 8x16. I drilled a 1 1/4 inch hole vertical though the
8” and plan to use four 6 inch pieces of 1” threaded rod
as the adjusting points. I have placing a steel plate on top of each
block (with a hole in it to match the hole in the block) and most of
the rod will be inside this hole with it being supported by the
shoulder of a nut on the steel plate. I can then use the nut at each
corner to jack up or let down the tub.

I guess you figured out what part I am missing…I have not yet
figured out what to place between the rods and the platform. I am
planning on using two beams. Either wood or steel but because I am
getting pretty high I would prefer a lower profile option. I was
thinking of using two 4” I-beams 90” long and then weld
the rod onto the I-beams 12” in from each side. Then place the
beams under the joists about 12” from each end. If I did my
calculations right each beam should have to support a weight of 566
plf….comments?

I have two I-beams now but fear they are not really strong enough as
they are a lot lighter then some I have seen and I don’t have
any specs. The beams only weigh about 5lbs a foot.

I might have access to some 4” beams that are a heavier (about 9
lbs a foot)

So I invite comments on any part of my plans. But being that it is all
completed except the choice of the two support beams my specific
question would be What is the minimum size of steel beam or wooden
beam I could use if I only use two beams and if I support them in each
of two OR three places.

Thanks in advance, Kelly