Can this floor take the weight?

[emporer]

Hi, i'm after a bit of advice if anyone would be so kind, we are having a log cabin/summerhouse built in the back garden to use as a sensory room for our disabled son, we plan to have a hot tub in there with other things but the tub will be the main weight. The cabin is 4m x 4m and we are having a concrete base laid to support the cabin, the interior floor of the cabin will be made of 100x50mm beams at 400 apart with celotex insulation between beams, the area where the hot tub will sit will have extra bits of 100x50 between the beams at around 500mm spacing. On top of all this will sit 25mm mdf boards as the floor surface.

My concern is the hot tub we are looking at is 2m round and filled is 2000kg so very heavy, would the floor we are doing support the tub?

Any advice is appreciated.

 

[emporer]

Forgot to add that the floor will sit directly on the concrete base.

 

[big-all]

do not use mdf or chipboard anywhere near a hot tub or wet area go for 25mm ply or propper planks
i would go for 250-300mm centers max under the hot tub area and slightly beyond to allow for flexability

 

[wakey77]

I would think the 4 x 2 at 400 centres would be sufficient however I would sit in on brickwork a minimum of 225mm deep then roll out a 100mm dpc and lay your rafters on that then noggin between all rafters to stop twist.
If you lay the rafters directly onto the concrete they will eventually rot.
I say 225 deep brickwork for 2 reasons it will keep timber away from any puddling water and it will also allow access for any of the local cats beneath which will in turn prevent rodents nesting.

 

[r896neo]

Worth checking with the mftr first as putting it on anything other than concrete may invalidate the warranty as they need a base with almost no flex.

 

[noseall]

100mm x 50mm joists seating directly on a decent concrete base will easily support the tub as would some 18mm screwed and nogged ply.

If you want belt 'n' braces use 25mm ply.

I would imaging 2000kg spread over the footprint of the tub is a lesser point load than an adult standing in one spot.

 

[emporer]

Many thanks for all the info guys, most helpful.