Laundry relocation waterproofing/drainage requirements

I'm looking at repurposing a 4m x 2.1m walkway/sunroom type area into an indoor laundry, as our current laundry is external to the house. I'm hoping to avoid spending too much on it (the plan is to extend/renovate in a couple of years when this space will be knocked down) ideally hoping to just having to fork out for a sparky for a couple of powerpoints and a plumber do the taps/drainage for the washer/tub, but whether that's feasible is the question I'm throwing out to the forum.

Full waterproofing - would this be an absolute necessity/requirement (according to building regs etc) or would it be ok without it, or just something basic like sealing the floor/wall joins? The flooring is tiles on a concrete slab, walls brickwork and fibre cement sheeting and the walls are external/visible on the outside (ie there's no soil etc built up against them).

Floor waste/drainage - again any need to do this? The doorway (from where I've taken the picture below) is an external one, so hopefully that and the fact this area is lower than the rest of the house means it wouldn't be required, as in the event of any flooding/overflowing any water can't get into the rest of the house and can flow/be directed out the backdoor.

Couple of pictures below, is there anything I've completely missed that needs to be considered?


The area in it's current state (used as a bit of a dumping ground

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A bit of a mockup of what the plan is

Hi Ben, you should be fine as long as there is a bit of fall to the rear door. Even if there wasn't I'm sure you will be fine for a few years if you plan on upgrading again in the future.