With the heat coming in and the prospect of not being able to travel much this summer due to prolonged de-escalation, they got a lot of people thinking: Can I install a swimming pool on my terrace or balcony?
The short answer: NO.
Thanks for the reading. Love me and follow me for more architectural advice.
The long answer: join me on this exciting journey of structural loads and calculations
Why can’t I put a swimming pool on my terrace?
The basic reason you shouldn’t put a swimming pool on a bridge is because not designed to support your weight. What happens is that with this answer we have no idea how much weight we are overweighting the structure.
Let’s do some quick numbers. A circular inflatable swimming pool 3 meters in diameter and 76 centimeters high like the one from Amazon has an advertised capacity of 3600 liters if it is 90% full (it is not completely cylindrical, otherwise it would be 4836 liters).
An inflatable pool can weigh 500 N / m2; the terrace floor is designed to contain 200 N / m2.
Knowing that the density of water is about one kilogram per liter, or 3600 kg of mass (3.5 tons(which is more impressive) spread over an area of 7.07 m2, which 509 kg / m2.
Do you know what are the general costs of calculating the technical building code (page 9.) for a terrace in a residential building? 200 kg / m2. (Actually 200 N / m2 because they are loads, not masses, but I made the change of units – and rounded – so that it is understood).
I mean, with a pelvis this size we make sure that the structure supports more than double the load for which it was designed.
This tweet sums it up nicely using more visual units of measure.
Let’s see how I explain it so that it is understood:
– A 3 × 3 swimming pool of 9 m2
– The weight of 50 cm of water is 500 kg per m2 (what a fighting bull weighs)
Even if you are from Pamplona, why not put 9 fighting bulls on your terrace? he
DO NOT PLACE SWIMMING POOLS ON TERRACES
– Fran Castro (@FranCastroEsp) 4 juin 2020
This also applies to small pools, as it is a matter of weight per area. Any swimming pool filled with 50 centimeters will have a mass of 500 kg / m2 and, therefore, it will assume an overload of two and a half times that expected.
A swimming pool with 50 cm of water weighs 2.5 times what the structure is capable of supporting.
For the calculation, we ignored the weight of the people who would enter the pool, but assume that we fill it 90% with them inside, and the density of the human body is not much different from that of water. .
But what about safety coefficients or load redistribution?
It is true that the calculations are introduced safety factorsBut it’s there for safety. In the event that the materials do not behave as expected, assume construction imperfections or faults, uneven load distribution, loss of bearing capacity due to exhaustion … Moreover, they are never superior to them . Even with this coefficient, we push the floor (which is under the terrace floor) and even the beams and pillars to the limit.
When it comes to inflatable swimming pools, even safety factors or load sharing are not enough.
On the other hand, it should also be considered that the slabs have a compression layer that redistributes the load so that it is assumed by a larger part of the structure, but this layer is designed more to distribute point loads, such as a shelf or a bathtub. In fact, about the baths, which are often mentioned in these cases: the filling of the bath is usually about 200 liters of water (i.e. 200 kg), a much smaller mass that can also be easily dispensed, nothing like 3.5 tons. some water.
So which inflatable pool can I put on my patio?
Continuing with the numbers we did before, we could theoretically put any pool on the terrace as long as we don’t fill it more than 20cm (which gives the maximum load of 2kN / m2). But of course, it’s literally a body of water. And here, in addition, we must add to the calculation the occupants of the swimming pool (75 kg per adult), because they cannot be considered as immersed in a body of water.
So taking this into account, the biggest pool we should put on the terrace is a small one for babies and fill it up to 20 centimeters high.
Even with a baby pool, the loads can exceed those expected in the structure
For example, in a swimming pool like this with a diameter of 120cm and a height of 30cm, it can hold up to 340 liters if filled to the top.
It is already 3 kN / m2 (300 kg / m2 to understand us), 50% more than general computational costs. What happens is, in this case, the compression layer is more efficient at redistributing the load, so for calculation purposes it can be considered that it is distributed over a larger area than that of the swimming pool. Even like that, they must not be filled beyond 20 centimetersBecause the swimming pool is not the only thing on a terrace.
In the case of balconies, a linear overload of 2 kN / m is added to the calculation at the edge of the slab, i.e. they are calculated to support a little more weight. However, we preferred not to consider it for different reasons: on balconies we support more, so there are more loads than the pool, and this linear load generally has more effect in the calculation of beams and pillars than in this slab, this is what generally gives when it comes to swimming pools in places where it is not touching.
Well my brother-in-law has one on his terrace and he hasn’t fallen
And a man who smoked like a roadman lived to be 105.
The terraces with swimming pools fall. Pass.
FOR UNKNOWN CAUSES
“For unknown reasons, the terrace gave way and collapsed on the garage below” https://t.co/rxP6TIFevP
– Asshole 🧻 (@doctorojete) June 3, 2020
So no swimming pools on the terraces and on the balconies. Please. If you want to cool off, a hose or, at most, a “bathtub” or its equivalent on the terrace.