Floor Question

[craig51]

I live in a house built 26 years ago. It is a terraced house.

My lounge goes from the front of the house to the back of the house, so the total length is 30feet. The floor boards run in the direction of the room, ie from front of house to back of house!

As its a terraced house, both walls are party walls shared with my neighbours.

At the moment, I have a 200kg tank sitting on the floor boards agaisnt a party wall, again running the lenght of the room. The footprint of the tank's stand covers about 3 floorboards.

I want to upgrade to a 4 foot tank, and this will come in just under 500kgs. What weight can my floor take?? The floor boards seem to me almost like tounge and grove, and from the outside, i have airbricks, so i think the floor must be resting on joists, which in turn are suspended from the ground!

 

[marshman]

have you seen a knot hole in the boards anywhere if not drill a 3mm hole somewhere and poke a piece of
wire through, your floor might just be fixed to counter battens on a concrete oversite. or over insulation on the concrete.

 

[craig51]

thanks for your reply much appriecated.

One question though, and bare with me as i am not a builder my any means, but how will sticking a piece of wire in the hole tell me whats under there?

Is it a case of drilling 3mm hole, and having a 'feel' for whats there, ie joists sitting straight in the concrete below, or suspended!

 

[Ossy]

I think that's what Marshman was getting at, just see how far you can poke!

What you're looking to do sounds quite reasonable. Even if the floor is suspended (joists bearing into or hung from the walls), you're putting the tank right at the ends of them, which if you're going to do it, it's the best place for it.

To find out for sure, see if you can take some floorboards up and find out what the floor construction is, how big the joists are, and what distance they are apart.

Roughly speaking though, if you've got a 30' by 4' tank that's 120 sq ft or 11 sq metres. 500kg = 5 kN, so the load from the tank is 5/11 = 0.45 kN/sqm. Standard domestic floors should be designed to take 0.5kN/sqm dead load and 1.5 kN/sqm live load. I assume the presence of the fish tank will preclude any other loading in the area, so you've only got to worry about the floor boards - you should be well within the capacity.

 

[craig51]

Ossy, cheers for your advice, i am going to go poking around on friday while i am off, and see if i can establish anything else.

The tank i am after is 4ft x 2ft x2ft, with a sump. So all that plus rock and equipment will come to no more than 500kgs. My only concern is having a 500kg tank sitting on an area of 8ft squared.

As you rightly said, the tank will right up agaisnt the neighbours wall, so should be the strongest point. There is no where i can put it so that the tank sat perpendicular to the floorboards, thus having more support.

Anybody else care to chip in!!!!

 

[joe-90]

500K is the weight of about 6 humans. You wouldn't expect the floor to collapse when you had a few mates around - so go for it.

 

[marshman]

the poke test !, if at a depth of approx 50mm you hit a hard surface
then the floor is counter batten over concrete, (can you see the nail heads ?), load all you want weight you want, if the wire keeps going
then you have joists, the joists or battens should be spaced at 400mm
centers so wherever you stand the new tank you'll certainly have two
bearers under it.

 

[craig51]

So, if i am reading this right, if it cant go anyfurther than 50mm, its as steady as a rock, if it goes further, then aslong as its over two battons, then i am also good to go!!!

 

[craig51]

OK guys, went exploring today, and wanted to share my findings and see what you all think.

The floor boards are 10cm wide each and approx 2cm deep.

From the top of the floor board to the ground, is 51cm.

I couldnt see any screws/nails to indicate where the battons might be!

So 1 foot = 30.48cm. Tank is 2 feet wide, so it will be sitting over 6 boards right up agaist a party wall. The house was built by Boland.

What do you all think!!!

 

[marshman]

go for it, why? because that depth under there your bearers are most likely 8x1&1/2 or 8x2's

 

[craig51]

marshman, cheers for comments, so i take it thats good then!!!

Do you think if i contacted boland, they will be able to confirm any of this for me?

 

[marshman]

they might but I can't help thinking you would get to know more in your local pub from people who worked on your house,
I don't know who boland are I guess they are a big company.
you might do a search for building regulation suspended floors eras 80's
but I'm fairly sure in the 70's the speck went to 8 inch.

 

[craig51]

re the pub, your probally right

For what its worth, i had the bathroom upstairs refitted last month, and the joist in there were pretty big mothers

 

[craig51]

OK, I have some actual measurements which should help us out.

Each joist is 50mm wide, and 130mm thick.

They are spaced 400mm apart suspended.

What load should this floor take???

My tank footprint will be 3ft x 2ft = 6ft sq2.

Cheers for all you help. The total weight of the tank plus water will be no more than 600kg.

 

[fastneattrowel]

OK, I have some actual measurements which should help us out.

Each joist is 50mm wide, and 130mm thick.

They are spaced 400mm apart suspended.

What load should this floor take???

My tank footprint will be 3ft x 2ft = 6ft sq2.

Cheers for all you help. The total weight of the tank plus water will be no more than 600kg.

sure done a lot of poking and measuring in 6 months craig put some sleeper walls in where the tank is sitting should be fine,although iam a master at 1 trade pretty sure that should be fine