You used to be able to lay additional layers of materials on top of the membrane, but Denver code now prevents that. 

The way we work with a slate roof is simply to remove all the slate from the section of roof where the solar array will go, then tie in to the trusses/rafters with standoffs and either use a rolled asphalt surface or a rubber membrane to seal the portion of roof under the panels, then replace some of the slate around the edges so it's a seamless transition from slate to solar.

I think if we redo that bathroom, we will probably do cement board with a membrane.

This is a flat membrane rubber roof.

-The ultimate solution is the installation of a capillary membrane.

I plugged in these rough numbers to the Rental Property Calculator here and the cash flow looked decent.I'd be looking to get a line of credit for the renovation budget and then do a cash-out refinance after 6 months.Renovation breakdown from realtorGarage - i would say put in anchor wall system and new membrane roof and new window altogether I'm thinking $4kYou'll want to tear down the plaster walls in the rooms upstairs and put up drywall: $6kYou'll probably want a new kitchen: $8k flooring appliances and cupboardsTear down of back garage and patio: $4kNew flooring and paint throughout: $5kbringing things up to code: $8kish?

Then the pour concrete over the membrane.

If the grout itself looks to be in pretty good condition (just dirty) then you have a few choices here...edited to add: if your shower floor leaks its not because of the grout....its because of the lack of membrane underneath the cement board or improperly installed drains...

After combining the weight of components (i.e. insulation, membrane, fasteners, and adhesive), typical installation weight is less than 2 pounds per square foot (10 kg per square meter) when .060" thick membrane (typically weighing 1/3 pound per square foot or 1.6 kg per square meter) is used.

I have seen people glue down hardwood on slab here in TX, personally I would never do it due to the moisture issues but you will probably get a few people saying it is ok.I would choose engineered wood floating on top of a pad with waterproof membrane (like the ones you use under laminate.