# Tank weight upstairs



## AdAndrews (18 Feb 2010)

Hi guys, I currently have a 125litre tank upstairs, its 80cm long, so, can only span 2 of the joists, although it is on both and as close as poss to a supporting wall, heres what ive calculated for the weight so far:

tank and cabinet and external filter weight: 20kg
water: 115kg(displaced)
sand and rocks:15kg(rocks are fake atm, so dont way that much, prob about 3kg)

so, thats a total of approx 150kg on 2 joists, each taking 75kg, but, can i add more weight?

Im thinking about getting some real rock, about 15kg, so would be adding another: 15kg

should i worry?


The house is approx 80-90yrs old, joists are *i think* 2"x4"-just a guess really...


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## Jase (18 Feb 2010)

If it's at first floor level it should be fine, the joists wont be doubled up beneath your bath and the load from that will be higher than your tank. Nothing to worry about I suggest. I have a 123l in the loft of a 120yr old house if that helps ease your mind


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## AdAndrews (18 Feb 2010)

ok, thankyou


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## Nick16 (18 Feb 2010)

Jase said:
			
		

> If it's at first floor level it should be fine, the joists wont be doubled up beneath your bath and the load from that will be higher than your tank. Nothing to worry about I suggest. I have a 123l in the loft of a 120yr old house if that helps ease your mind


but the bath is not filled 24/7. 
its the prolonged weight that is more the issue.


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## Jase (18 Feb 2010)

It's the loadings that are the issue. If the joists are not man enough to take the weight of the bath water 24/7 then they are not man enough full stop. They are calculated to take the worst case scenario


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## Nick16 (18 Feb 2010)

often joists will bow slightly and over time this could cause them to weaken and crack. 
the initial fill up wont be a problem i dont think ad, but im not so sure 6 months donw the line. Think of the stresses lasting months and months. all it could take is 2 people standing infront of the tank looking and the extra 100KG+ could be a problem, whereas it might not be in the first few weeks.


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## AdAndrews (18 Feb 2010)

Ok, thanks Nick,


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## Jase (18 Feb 2010)

With all due respect Nick, I understand where you're coming from however I do have some idea of what I'm talking about with regards loadings and joists as I work for an Engineering/Surveying firm. 

Obviously, your house, your risk, but in my opinion there is no risk.

Ad, if in doubt ask a professional, I'm sure a Surveyor would happily come to your house, lift your carpet and your floor boards and measure your joists and then tell you the same thing as me, then charge you Â£100 per hour or so to do so


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## AdAndrews (18 Feb 2010)

Ok, thanks for your help


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## jellyfish6 (18 Feb 2010)

AD, it's impossable for anyone to tell you if it will be ok with this info.  My house is about 100years old and also has 200mm deep joists.  I have a 260l sat on my floor and yes over the last 10 years there has been some movement (you can see this as there is a larger gap between the skirting-board and floor).  

It is important that your tank is at right angles to the joist, the fact that the tank is near the bearing is good as this is where the joist is at it's strongest.  However, in a house of this age, lots of alterations may have taken place that will weaken the joist. New central heating is normally the biggest problem - if the joist has been drilled or notched outside the "drill zones" then these holes or notches can significantly weaken the joist.

In short, the only way you can be certain is to open-up the floor, take all the measurements and then calculate the stress - none of which I did!

The good news is that the timber used in your house 90years ago is likely to be beter that tradional cut joists today they should eastly be equal to C24 timber or the old SS grade.

TRADA table are available for calculating loading however they only assume a concentrated loading of 1.4kN and a max UDL of 1.5kN/m2

Good luck!


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## AdAndrews (18 Feb 2010)

cheers! I did read something about 1.5kn/m2 earlier as the max, didnt know what it meant mind.


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## jellyfish6 (18 Feb 2010)

Sorry, should have said.....The TRADA tables are for calculating the suitable joist size for the span of the joist - not much good for what you need.  But it gives you an idea of the loads you joist will normally take.


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## sanj (21 Feb 2010)

Place the tank and cabinet on a 18mm plywood base that spans the joists, it will distribute the weight. Personally I would not be too worried about a 125 litre tank, i have had a lot more than that on my first floor. However it is true every house is different.


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## squiggley (21 Feb 2010)

jellyfish6 said:
			
		

> The good news is that the timber used in your house 90years ago is likely to be beter that tradional cut joists today they should eastly be equal to C24 timber or the old SS grade
> Good luck!




I have my Osaka 155l on the first floor in my place which was built approx 18 months ago and uses floor joist like these





Like all thing modern looks cheap and nasty but the tank has been in place for the past 12 months with no problems.


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## jellyfish6 (24 Feb 2010)

Squiggley, these are "engineered" joists used by a lot of builders these days - they are a lot different to the traditional joists referred to in my post.


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