In front of my house I've got a decent size garage can hold a car and a 2 wheeler with ease. This is unused space for us and we want to spend some money and turn it into a 1 bed annexe to rent out to help us with our mortgage payment.

Anyone who have done this kind of annexe please 1. tell me whats all the job that needs doing
2. how much would it cost...
3. does my council tax increase
4. does my bank has to be told about renting out 5. how do I go about measuring the electricity the tenants should pay?
6. we might have to move water pipe [not sure] we have the mini water softener installed there any cost idea ?
7. how much whould a general quote a plasterer would give for plastering garage?
8. anything I'm overlooking? will I burn my hand doing this or is this a good investment?

please releive me of my stress or I'm going to eat myself to .....

I think you'll need planning permission if you're planning to rent it out as a separate unit.

I gathered I need building reg... didnt think I needed plannign permission. Will see that.

About the other bugging questions someone anyone please!!!

If it adds value to the house then its likely you're going to end up in a higher council tax band.

You should inform your mortgage provider if you let out any part of your home as it creates a 'risk' that wasn't there when you took out your original agreement - I doubt they will cause any problems though.

You also must inform your insurers if you rent out any part of your home - they could well use that fact you havent done so to wriggle out of any claim.

Jim G good informations I never thought about these. Thanks!

will talk to them ones before starting other works

If your annex has it's own front door then it will be classed as another property and attract a separate council tax bill. You might be able to get your house down graded as you are making it smaller but would have to check with the council. My friend rents an annex and her rent is inclusive of all bills (not sure about the council tax though). You could split the gas and electric supply but might be more trouble than it is worth.
You'll need to make sure that the external walls etc are suitable insultated to pass building regs.
If you have a mortgage you need to inform your mortgage lender of what you plan to do and you may attract a 'buy to let' higher rate of interest - depends on the bank though.
Plastering can be anything fro £120 - £250 per day depending on where you live and who you get to do it.
Ask yourself if you really want to be living next door to tenants? Are you prepared for the 10pm knock on the door because something needs fixing on a Sunday night?

Good luck!

I think your best bet it to work out of the variables.
Look at how much It is likely to cost, how it may affect your Council Tax bill and how much you expect to earn. Also worth speaking to some letting agents about how much you are going to be able to charge.
Here is some more info about garage conversions.