I am putting a megaflo HW cylinder in the renovation and need to
construct the floor of the airing cupboard (which is above the
staircase).

The weight when full of the particular model will be 228Kg and I was
wondering how I ensure that the floor it is standing on is strong enough
for that weight.

Is their an easy way to calculate the joist size I need to use?

Cheers
--
Martin Carroll