Hi Guys,

A little off topic but i am sure that this is where the experts will
be and will help me out !! (A little Flattery always helps !!)

I am building a Cover for a Spa (in USA - Jacuzzi)

The external dimensions are 2.4 x 2.4 metres. This is a heated spa
that runs at about 40 degress Celsius.

The design requirements are as follows:-

1) Covers must be able to hold a 150KG weight across their longest
span (we have two rottweilers who love to sleep on the spa in the Day
to stay warm !!!) Also as this is in a recessed position in a deck
there is a very real chance people will walk on this.

2) The covers will be exposed to the heat rising from the water as
well as UV from external SunLight

3) The covers must provide thermal insulation to retain the heat in
the spa.

4) Light Weight (20KGs or less per cover) so they can be easily lifted
by my wife

My Design therefore was as follows:-

1) Polystrene Foam Core 50 mm thick.
2) 5mm Polyurethan covering bonded to this all over
3) Create the covers in two pieces = 2 x 1.2m x 2.4m

Fibreglass Top and Bottom and sides - insert a central Fibreglassed
Balsa Beam across the 2.4 metre length and glass in place for
additional strength

I have been told that the resin i intend to use reacts with
Polystyrene and hence covering with Polyurethane will stop this
occuring - anyone have any experience on this. ??

The covers will not need a fancy finish - i intend to paint them later
(is it possible to paint Fibreglass ??)

My basic plan was to contrusct the Styrene and Polyurethane sheets and
to then pain the fibreglass matting on wet on wet on the bottom, once
dry then do the tops. Finally do each edge with strips of matting that
overlap on the tops and bottoms to lock it all together and seal it
off.

Does this sound feasible ?? Am i missing anything ???

regards

Craig Curtin