Joist strengthening?

[DV79 1]

Hi,

I've just made a somewhat impulsive ebay purchase, which is a 4X3X2 Marine fish tank, with a filter/sump built into the same cabinet. All up weight of this, when full of water, will probably be around 500kg.

I'd LIKE to put this upstairs in my study, but have some concerns on floor strength. I live in a victorian terrace. The room in question is about 11x11 excluding bay, has 6 1/2"-7" x 2" joists (which appear to be in good condition) and is floored in 6 3/4" x 1 inch pine.

The joists are between 13-14' apart.

I would plan to put this tank more or less in a corner, to ensure maximum available floor strength.

My initial intentions are to put a wider piece of structural board down, to ensure that the stand (24 inches wide) straddles 3 joists rather than just 2, which is otherwise would.

is this floor likely to be sufficiently strong to hold this weight?

If not, what would be the easiest, cheapest way to reinforce it?

Any opinions would be greatly appreciated.

[verne 1]

the victorians, like many from before and after, built many very good houses - but also threw up a lot of rubbish! a lot of the rubbish from the barratt type builders of those days is still standing - and i am living in one of them now. perhaps you are too?

building materials were fairly expensive in those days, so was labour - in fact things weren't much different from now except there was no diesel lorries to haul stuff around and there was no power tools to make work quicker and easier.

houses that were built for the letting market would have as many corners cut as were needed to bring them in within the budget...

substandard mortar, bricks re-used from previous demolitions, substandard bricks, inner walls would be where any brick ends, cobbles and odd lumps of coal would be used up. the further up the house and at the back of the house was where most of the cost saving took place. a lot of money was saved by using second and third grade timber and adze cutting the rough sawn boards to fit - a lot of money was saved by having floorboards only planed one side...

a lot of such houses were built without proper foundations or incorporating bits and pieces of the foundations of previous houses...

half a ton would be a lot of weight to put on a floor upstairs if your house was without any defects. it would probably stand it quite safely until the floor began to become permanently warped as timber will if it is subjected to a great load for a long time. my concerns are about the unknown factors of the timber grades and the quality of the building and of the foundations.

my advice is don't!

if you must go ahead then pay a professional to look at it first so you can sue someone if there is a problem...

if you have sufficient ceiling height in the room below you could strengthen the floor and spread the load into all the walls by installing more joists at right angles to the originals and underpinning your floor. you can then enjoy an open beam look or intall a new ceiling...

alternatively a couple of nicely painted acro-props would provide extra support.