How do you calculate how much weight a balcony can bear?

fgo · 12 Jun 2021 at 9:20 PM

T tobbbias said:
I mean, the distributed load probably comes mainly from the snow load that occurs when half a meter of wet snow lies there in March... ? I think the balcony will survive. Just don't lay the decking too tightly so that the meltwater can drain through. Remember that wet decking expands. So even if you have large gaps in the summer, they can become completely tight on wet winter days.

No, it does not.
If you read a bit, you see that the distributed load that balconies are designed for is 3.5 kN/m².
While the snow load is different for different parts of the country.

When I had a dialogue with an engineer during the training, the load combination with person and snow load is not considered. Because the amount of snow prevents you from getting out onto the balcony.

Rolle85 · 12 Jun 2021 at 9:20 PM

I live in Göteborg

larsbj · 12 Jun 2021 at 9:22 PM

fgo said:
No, it doesn't.
If you read a bit, you'll see that the widespread load that balconies are designed for is 3.5 kN/m².
While the snow load varies for different parts of the country.

When I had a dialogue with a designer during my studies, the load combination with people and snow load is not obtained. As the amount of snow prevents you from going out onto the balcony.

That's probably true, the OP seems to live in snow zone 1.5 or 2.
Quite right, you don't need to calculate both, not even as a load combination.

Rolle85 · 12 Jun 2021 at 9:29 PM

It might snow here on the west coast but not like the rest of the country. 2dm maybe for a few days

hlph · 12 Jun 2021 at 9:36 PM

R Rolle85 said:
Okay, then I have a problem. I'll need to start using double 170x45mm since my free spans are 3.29m

2 pcs 170x45 mm roughly equates to 1 pc 220x45 mm when looking at deflection. The deflection depends on the height cubed and linearly on the width. From a strength perspective, 2 pcs 170x45 mm are stronger than a 220x45 mm. This is because the bending stress depends on the height squared.

tobbbias · 13 Jun 2021 at 12:19 AM

fgo said:
No, it doesn't.
If you read a bit, you'll see that the widespread load that balconies are designed for is 3.5 kN/m².
While the snow load varies for different parts of the country.

When I had a dialogue with a structural engineer during training, the load combination with person and snow load was not achieved. Because the amount of snow prevents access to the balcony.

Okok. You probably know best

When I calculated landings for stairs, which is almost equivalent to a balcony, I used 3kN/m2 in Svedala, but 5kN/m2 in Germany. Thick Germans

but the funny thing was that the point load in Sweden was 3kN while it was 2 kN in Germany. However, they had smaller feet in Germany because there the point load was applied on 5x5 cm but in Sweden, you had to use 10x10 cm

So, I still think that TS can use their balcony

Design rules are good tools if you want to cover your back. But common sense often suffices. If I remember correctly, the balcony was 8x3.3 m. That area times 350kg/m2 becomes 9.2 tons. Or 90 hefty guys...
I guess there will never be more than 25 hefty ones on that balcony...

tobbbias · 13 Jun 2021 at 12:24 AM

T tobbbias said:
Okok. You might know best
When I calculated for stair landings, which is almost equivalent to a balcony, I used 3kN/m2 in Svedala, but 5kN/m2 in Germany. Thick Germans but the funny thing was that the point load in Swe was 3kN while it was 2kN in Germany. However, they had smaller feet in Germany because the point load was to be applied on 5x5 cm whereas in Swe you could use 10x10 cm
So, I still believe that TS can use their balcony
Design rules are good tools if you want to cover your back. But common sense often suffices. If I remember correctly, the balcony was 8x3.3 m. That area times 350kg/m2 becomes 9.2 tonnes. Or 90 hefty guys...
I guess there will never be more than 25 hefty people on that balcony...

However, what I dislike when you build a bit lightly is that you can get unpleasant natural frequencies which can lead to a bouncy structure. That can really bother me. But TS will surely notice when they jump around on the balcony if it turned into a trampoline or not

Fotografen · 13 Jun 2021 at 12:55 AM

R Rolle85 said:
I live in Gothenburg

De va la gött...!

In any case, either you let a building engineer calculate according to standards, or you do it the old-fashioned rural way (based on a good supply of wood from your own forest) which means you over-dimension. Significantly.

Rolle85 · 13 Jun 2021 at 1:45 PM

Now I've jumped a bit. Don't feel any bounce?
Bought a sample plank for decking 145x34mm. With this I have 1cm clearance to the balcony door. Should I go for 28mm decking instead or will my 34mm shrink to about 30mm in a year?