how much gravel do i need?

[soppypreggyloon]

we have a section of decking in the garden which is rotten and slippery. it needs to come out but i don't want to replace it with more decking.
there's gravel underneath - probably 2-3cm pieces. i want to top it up to bring it to the same level as the rest of the patio area. how much would i need?

cheers all! :)

Without knowing how deep you are talking and what the area to cover is it's obvioulsy impossible to tell you...however here is a gravel calculator:
www.earthproducts.net/do_it_yourself/calculators_gravel.html