How do I soundproof a floor for impact and airborne noise?

Edit Subject

Dear Sirs

Have been doing little bit of research re sound proofing floor between two flats-obviously I unfortunately live in the lower one! Im just finding all this information fairly confusing-this seems to be not a precise science-slightly hit and miss and fairly costly. So would really appreciate some advise.

Perhaps if I provide more information it might help. Block of flats purpose built after say around 1940's. Have full access to top flat-its actually owned by my mother-so no problem there. Floorboards tongue and groove-so whenever you touch them its just a nightmare-so if you are talking about lifting floorboards you might as well replace the whole floor. The actual floorboards are very narrow aswell about 4"-and in all the information I have seen you have to seal the gaps between floorboards before layiong mat-so maybe this would be preferable anyway-since would be huge job and the apparant percentage noise seepage if you fail in this process just wouldnt be worth the risk. Then floor cavaty very shallow around 2"-then concrete ceiling (which should insulate sound-but seemingly doesnt)

Skirting board is tiny, from carpet to top around 4"-so little scope there.

Main problem airborne sound-but if your spending this sort of money and effort though wouldnt mind eliminating impact aswell if feasible.

I was wondering about putting down some ply or something so didnt have to seal each gap and then placing double matting over etc. But how does this work-do you put the carpet gripper through the matting then after??

Would really appreciate some advise and idea of costs. Floor space around 35m2

Many thanks