I’ve been looking to get an inflatable pool for my rooftop. The pool is 133cm in diameter and 76 cm deep. The math i’m seeing would put the filled weight somewhere around 27,000 pounds. I live in a typical, older, 5 story apartment building that you see everywhere in taipei and taipei county. I would assume that my cement roof would withstand the weight as I see huge water bins on nearly every roof including my own. Not to mention those bins are some 11 feet tall which would add a lot more weight per square inch than a pool. I’ve also seen the drains of roofs plugged during typhoons where the entire roof fills with water, and i’ve still never heard of a roof caving in. If there are any builders or engineers out there, do you figure this is something that i need to have a consultation with a structural engineer about? or is that kind of weight fairly insignificant to the structures of these concrete buildings? Again, i’d prefer input from those who know what they are talking about rather than witty remarks and observations from random forum browsers.
Are the figures for the diameter and depth correct? I just ran the numbers and came up with 1056 liters of water, which would weigh about 2,328 pounds.
Your calculation is wrong as pointed out by cranky. 27,000 pounds is roughly equivalent to a dozen small cars. Your rooftop can easily handle a pool much, much bigger than the one you would like to use. Go for it, it sounds like a fun idea with the weather we’ve been having. I’m not a structural engineer, but I say this with absolute confidence.
Correction: We posted at the same time. I don’t know the math for this, but 27,000 pounds sounds too heavy. You’ll definitely need to ask an engineer about this, in my opinion.
I’ve been looking to get an inflatable pool for my rooftop. The pool is 133cm in diameter and 76 cm deep. The math I’m seeing would put the filled weight somewhere around 27,000 pounds. I live in a typical, older, 5 story apartment building that you see everywhere in taipei and taipei county. I would assume that my cement roof would withstand the weight as I see huge water bins on nearly every roof including my own. Not to mention those bins are some 11 feet tall which would add a lot more weight per square inch than a pool. I’ve also seen the drains of roofs plugged during typhoons where the entire roof fills with water, and I’ve still never heard of a roof caving in. If there are any builders or engineers out there, do you figure this is something that I need to have a consultation with a structural engineer about? or is that kind of weight fairly insignificant to the structures of these concrete buildings? Again, I’d prefer input from those who know what they are talking about rather than witty remarks and observations from random forum browsers.
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I had a pool just a little smaller than that on my rooftop, and it was great. I say go for it. What’s the worst that can happen?
With a pool diameter of 333 cm (or, to make the math clearer, a radius of 166.5 cm) and height of 76 cm, the water would weigh about 14,592 pounds (6,619 kg) if the pool is full to the brim.
hmmm…this decision is not getting any easier to make…although i’m not directly below the thing…not sure i want to foot the bill for rebuilding, and or the medical costs associated with falling through a cement floor inside of a 6 ton pool of water…i’m getting that this is not an obvious yes or no answer and that i should seek a structural engineer…
there may indeed be a 20 ton water tank on the roof, but you can bet your bottom dollar that that tank is supported bloody well by things built into the place at the beginning… extra beams, columns, etc. Pitch a 6 ton swimming pool on some random piece of unsupported roof and you may regret it. If you must, then pitching it directly over an intersecting pair of walls on the floor below would be your best bet without too much risk. But if you’re not dead certain what’s underneath, then I would be reluctant.
A kids paddling pool, yes. a 2 meter jacuzzi, pushing it. a 3.5 meter pool? nope.
OK, so according to the math provided above, the pool when full is going to weigh about 14,592 pounds. There is an easy weigh to test if the roof can support this weight: get 73 people (if they are an average Western man who weighs 200 pounds - you will need more if the people you can collect are lighter) - i.e., get the number of people together whose weight adds up to 14,592 pounds. Maybe have a party up on the roof, and invite some of your fat friends to make up for the skinny xiaojies. Then have everyone hop up and down a few times to see if the roof can support the load.
(Just as an aside: not only would I not trust the average Taiwanese building, I would also not trust the average Taiwanese structural engineer.)
If the diameter is about 11ft and the total weight is around 15,000lbs then you are looking at around 157lb/sq ft. I would never add a live load of more than 40lb/sq ft to a structure with unknown properties (you have no idea how thick the concrete is, its elasticity, shear strength etc. and more importantly the strength of whatever is framing the floor).
For a while I built recording studios in residential houses and worked out with a structural engineer that 40lb/sq ft was the absolute max load we would consider safe unless a full structural analysis was done. You will probably find a similar recommendation from aquarium suppliers.
A well built reinforced concrete floor will support several thousand pounds per square inch, but you are talking about a roof which was never intended to bear large loads and a frame with unknown properties, so personally I think it’s not worth trying.
My brother built a house many years ago, and installed a Scandinavian stone fireplace weighing approx. 3 tons (3,000kgs), he had to support the floor by building support walls in the basement. (the fireplace was about 1,5 sqm). Concrete quality (floor) in my home country is pretty good. I have no idea what concrete quality and thickness they used for the roof at your place.
Just figure out how much weight per square whatever it puts on the roof and go from there. Eventually, put some extra support under the pool, spreading the weight.
While I’m at it: Does the appartment below have supporting walls? Try to possition the pool over a wall or a crossing of walls. That would enable it to carry lot’s of weight.
I had a pool which I calculated held five metric tonnes of water on my roof last summer.
I went downstairs and checked that there was a solid, supporting wall running more or less half way through where I wanted to put it and then put it up.
It was fine, mei wenti, had it up for a few months.
Make sure your drains are clear when you drain it though – leaks caused by draining a pool as opposed to ‘natural’ water damage, are a sure fire way top annoy your neighbors.
Also bear in mind that if you are going to leave it up, and others have access to your rooftop that you should cover it when not using it, and consider putting up a sign warning kids off using it-- I simply told the parents of the kids in my building that it wasn’t acceptable for them to use it, and they were fine with it. i think they understood where my concerns came from (unsupervised kids, water etc). Mine had a filter and stuff, so I didn’t drain it every after every use.
And the weird thing was no-one ever mentioned it to my landlady.
unfortunately, the load bearing walls from the floor beneath continue up as 1 meter walls on the roof…that makes them very difficult to utilize…might have to rent two parking spaces and put my pool in the garage…ha…it really is a shame though…I have a 50 ping private roof and i’ve been growing trees and a garden for 3 years, installed electricity, stereo and porthole lights, gas bbq, table and chairs with umbrella, backyard games…i really just need the pool and I’m set
Your rooftop can easily handle a pool much, much bigger than the one you would like to use. Go for it, it sounds like a fun idea with the weather we’ve been having. I’m not a structural engineer, but I say this with absolute confidence.
