Hi Maggie
It would be the same formula that you would use for your domestic cleaning services.....to pay for your staffing, materials, costs....then a bit of profit ontop!
It sounds like the communal areas are not the standard two or three storey blocks?!? But as you said, a large exclusive block of apartments....
Over my way, a three storey block goes from £10 - £13 per weekly clean.
The thing to not forget is that the tennant will be paying for the cleaning service, maintenance, grass cutting, painting, bins emptied etc etc etc in a monthly charge.
So if you have my example above of a three storey block @ say £10 and there are six apartments in there = £1.67 per appartment per week charge....thats pennies!! So out of their monthly maintenance fee £6.68 is towards the cleaning. Some tennants are charged up to £80 per month maintenance fee!! I am sure you could charge more than that.
Work out how much it would cost if each apartment was charged £00.00?? per week x the number of apartments in the block? See what happens....remember if they are exclusive flats, you could probably charge a little bit more per week.
This may give you a guide as to how much to charge
They like it too if you place near the front door or on the notice board a schedule for the cleaning. You would include on it the date cleaned and signed by the cleaner, a small spec as to what will be cleaned and also a space to leave any comments by the cleaner or the tennants.
You could also advertise your domestic cleaning business on here to for the tennants. When they see the communal cleaning being done on a regular basis and the quality, they will use you.
Hope this has given you some ideas to throw around in your head!! and hope you get the communal cleaning there too.
Regards
Tim