Susie, you are an inspiration! My mum was widowed at 50. Is now 77 years old and is as independent as you obviously are. Though she hasn't taken on a full bathroom reno yet. Good on you!! I also live alone and know hard it is tackling these projects by oneself. Watch your back though carrying heavy sheeting - it will catch up on you if you overdo it too much now. Us independent types feel bad asking for help, but there will always be someone that could give you a hand carrying the really heavy stuff. Your bathroom looks identical to mine, except my window is a bit wider I think. I have gone ahead and stripped everything out including the terazzo floor and now, because I am unsure whether to raise the house in the future or not, I have as a result, been showering downstairs for 6 months (whilst I complete a grad. dip course in education) having a garden hose attached to the old laundry tub taps and several shower curtains around a makeshift area. I got through winter so might it be this way for another 6 months...I would be interested in seeing the before (and after pictures of the rest of your place).

what is the size of the gap between door and door frame? We have a waterproofing system on our wooden doors. Two parts: First is the the metal attachment to the frame, this is about 1cm in height. Second is the metal and rubber attachment to the door, this is about 4cm. So the waterproofing install is about 5cm in total. I have attached photos for reference.

You have said in your opening post, “you have been told to waterproof hob”. So wouldn’t that be your answer, especially if the balcony is higher than lounge room now. Before the high hob would of protected lounge room from water entering. You have changed that, so would now need waterproofing.

The door is to a living space, the builder wants ro fill the cavity with grout, however I’m concerned about moisture transfer between brick to inside slab. Due to the outside 2 brick heights drop, the weep holes where not installed as it would allow water in after the external patio to these doors was installed. The plastic you see is the termite barrier that folds over the bricks and sits under the doors.