What to do with a downstairs area, no windows, no gravity drain to sewer (BCC council)

I have a large concreted area under my house (approx 8m x 8m with 2.8m ceiling). No windows due to sloping block of land, limited natural ventilation, limited natural light. Due to sloping land, gravity drain to sewer connection is not possible.

I'm thinking of building in walls to make it into a second living room, private office, TV room etc. I'd like to put a bathroom in - use electric pump to lift grey and black water to then gravity drain to sewer. Forced air ventilation and the existing house design will allow for _some_ limited natural light if I make one of the walls with large translucent panel (room will be under-next to a verandah which leaks some natural light)

I'm guessing no council would approve a granny flat in this situation. I'm within Brisbane City Council.

What are my likely options? Just trying to get some ideas together before I spend money on a building certifier.

 

With the recent heavy rain falls in Brisbane and living on a slope was there any water coming in too the underneath section's..
With the granny flat -just have a read within this site about the legal obligations with the BCC and granny flats ..

 

I've no idea about regulations in BCC, but you could put in a large cinema/media room. Maybe a gym. Look at The Block with what they did with the basement areas for inspiration.

 

Thank for the bcc site info

prior to pouring the slab we upgraded the drain external to the house. A retaining wall under the house has ample gravel and slotted pipe to channel water.
With the heavy rain the retaining wall stayed dry.
A gutter between the retaining wall and slab collected maybe a L of water which drained to external drainage pipes. the slab has stayed dry.
When we upgraded the drainage we made sure to have ample fall to drain water.

If we close in the wall, dampness isn’t expected to be a problem other than in heavy extended rain. Will need some forced ventilation on a timer to keep the room fresh.

 

I’m leaning towards this.
Was looking at soundproofing designs. Seems two layers of gyprock with non overlapping joints and extra care to seal all air gaps is the minimum.

 

Gre
Still trying to work out if a pump to lift sewerage is accepted under the building code. Having a bathroom and mini kitchen would make the room very usable.

 

Don't know if this helps but Saniflo have a list of plumbers that fit their pumps. Calling one plumber on this list might be helpful as they could tell you if they'd done something similar:

Where to find us?

 

https://www.kogan.com/au/buy/proteg...t-basin-shower-washing-machine-dclmacproa4l5/
This pumps are cheaper than Saniflow pumps.

 

Definitely cheaper, good find. My suggestion was more to get some info about what you can do re BCC. Sometimes it's worth paying a plumber that's done similar jobs to come out and tell you what is possible.

 

Kogan ...A **** pump that pumps ****.

 

A certifier may be the very place to start. They will know what can and cant be done.