Laminate floor to support weak fibreboard?

Apologies for the newbie question...this is not my area of expertise and I'm a bit out of my depth!

We have a fairly poorly built 'sunroom' on the side of the house. It has a fibreboard floor (not my choice...) which is about an inch thick and is laid on top of a row of wooden slats which are approximately 60cm apart. It currently has a lino covering.

Unfortunately, the fibreboard has got damp by the back door and by the washing machine door, meaning that two areas which are about the size of a small plate have lost a lot of strength. You can still stand on them but they bow quite badly and will eventually give way. [attachment=0:dap8i62y]DSC01602.JPG[/attachment:dap8i62y]

We considered replacing a couple of the fibreboards with waterproof ply but this would be tricky as there is a large built in corner unit for the washing machine which sits across two of them which would have to be demolished. I would rather not replace the whole floor as we may well demolish the whole outer building in a few years time, finances permitting (and it is the least used room in the house)

My current plan is to
- dry the floor out (I don't think any water is coming from underneath)
- use 8mm tile effect laminate flooring (approx 120cm x 30cm) to go on top of the fibreboard across the whole floor. I would place the first board over the centre of the weaker areas and place the rest of the boards around those.
- put a silicone seal around the edge to stop the water sneaking under from the door

My question is whether that would be strong enough? I tried it with a single laminate sheet and it feels strong enough, though there is some flex. I could use 12mm instead if I could find some I like. I'm hoping for a 5 year solution rather than a 20 year solution.

Also any thoughts on whether it would be advisable to use glue and/or a laminate underlay?

Sorry again for the long newbie question but I'm a bit stuck!