Loft Conversion .. Steel Joist Strengtheners

Hi..

I'm converting the loft on my victorian terraced. i have 2m head height on a good percentage of the loft and don't want to lose this.

However my joists are only 3inch and obviously if i use timber to meet regs these need to be i believe 9 inch.

Is there anyway i can keep the current joist height and strength these with steels or even replace. I do have nearly 9ft of bedroom height which i can eat into if i must but the mess and cost or ripping it all down seems way over the top for what i will gain.

and i was hoping the costs of steel strengtheners would be much better.

At present i'm in the planning and ideas stage.

I've installed a set of stairs into the loft purely for access. for future use i've left then 12 inch short of the current joist level. This is so i get all the correct fall on the stairs. When complete the loft i will need to install 2 additional steps at 90 degrees to my current stairs.

Thx for any advise given.

no is the standard answer
quick google
http://www.broxbourne.gov.uk/environment_and_planning/building_control/timber_span_guide.aspx
http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_A_1992.pdf

nearly finished mine ( got slowed up ) my joist are 150 but adding packer means the top of the floor to the wall plate is 150mm( joist) 19mm (packer) 22mm (floor) other about 3000mm
as for the stairs i ended up with a non standard 4 winder to get correct pitch etc