increase loft floor strength

[adwt2004]

I need to fit a hot water cylinder / cistern in the loft space. I have no where else in the house where it can go. The tiny airing cupboard won't accommodate. The loft is huge but the issue is with the strength...

I have 4 by 2 joists and the tank/cistern capacity is 138 litres plus weight of empty tank so all together around 165kg ish. There is 1 wall seperating the bedrooms that I presume is load bearing. I live in a mid terrace and this wall runs from one neighbour side to the other so not like i can rest new joists on two walls.

Can you give me any ideas of what i can do? Really don't know how i can improve the strength. it takes my weight fine 80kg if any consolation...

can you guys help?

MOD 2

you have already asked this question in building

 

[masona]

Find the two loading bearing wall, run extra bigger joists depending on the span then exterior plywood for the base. You might have to pack the joist up a little with small section of plywood under the joists to clear the plasterboard or plaster & lath ceiling.