Can I make the addition of loft floorboards (for storage) even though the insulation will be smaller quantity than the recommended 270mm? I am new to the home development game. My loft have...

I am new to the home development game. My loft have joists that are 100mm glorious, with 100mm blanket insulation between them. I would similar to to add chipboard flooring so that the loft can be used for storage.

However, I own read that lofts are supposed to have 270mm gluey insulation (i.e. theoretically I should affix 170mm blanket insulation at right angles to the joists and the current insulation). If I do this though, I won't know how to nail boards down as in that will be nothing to protected them too.

If I keep the insulation as is and make a payment the boards, will I cause problems for myself when I come to go (i.e. will it become law to own a certain depth of insulation)? Can someone who understand this stuff please help? Thanks.
Answers:    you can purchase insulation from b/q which i bought (a bit more expensive ) it is made up from different types of layer that only desires to be 100mm try to check it out on there net site
If you resell and it doesn't meet local building code a buyer will more later likely want to knock past its sell-by date the price to cover bringing it to code or may require you to do it before they buy.