Beam in pressure treated wood

[Nygge72]

Hi, I am planning to build a deck on pillars and was thinking of the dimensions 7x4m. My question is what dimension of supporting beam/floor joists I need and if that will be sufficient?

 

[huggan]

Here's a classic that is perfect for determining dimensions for decks:

 

[huggan]

Let me know if you need help reading the table.

 

[Nygge72]

Let me know if you need help reading the table.

I assume that if I am to have a deck that is 4m deep, I should go for 2 rows of posts with "at most" 2.4m between the rows and then it's 45x170 I should go for? Have I read/thought correctly then?

 

[huggan]

Assuming you attach a bearer beam to the house and then two rows of piers for this for 4 m.

If you look in the column for 2.4 m and 45*170, it gives you 1.8 meters between the piers.

If you look in the right table, you need a floor joist that can handle at least 2 m between bearer beams, which is 45*145.

 

[Nygge72]

Assume you attach a support beam to the house and then two rows of concrete piers on this for 4 m.

If you look at the column for 2.4 m and 45*170 it gives you 1.8 meters between the concrete piers.

If you look at the right table, you need a floor joist that can handle at least 2 m between support beams, which is 45*145.

Thanks. Now I know. Many thanks

 

[Nygge72]

Thank you.

I went to measure at the construction site today and received the question in this way. If I don't attach a carrier beam to the house and have a freestanding deck. Can I manage with 2 rows of footings if I have overhang on each side?

I'm thinking deck size 4x5.5 or 3.5x5.5m

What dimensions do I need then and how many footings to manage with 2 rows of footings?

 

[Nygge72]

I assume you attach a carrying beam to the house and then two rows of posts on this for 4 m.

Looking at the column for 2.4 m and 45*170, it gives you 1.8 meters between the posts.

Looking at the right table, you need a floor joist that handles at least 2 m between the carrying beams, which is 45*145.

Still have to ask, I feel. Now I've been measuring at the construction site and have the choice of a deck of 4x5.5m or 3.5x5.5m.

If I'm not putting a carrying beam on the house, which I probably won't do, is it possible to still manage with 2 rows of posts if I use a certain overhang on each side? What size should the carrying beam, floor joists, and post spacing be, and how much overhang (preferably not too much)?

 

[Sharky58]

Have you seen these two simple calculators:

https://www.byggbeskrivningar.se/dimensionering/golvbjalklag-ute/

https://www.byggbeskrivningar.se/dimensionering/altan-utan-takkonstruktion/

/Göran

 

[Nygge72]

Have you seen these two simple calculators:

[link]

[link]

/Göran

Yes but was unsure if tryckt virke and konstruktionsvirke were/are the same thing?

 

[Sharky58]

Beijer says that pressure-treated building studs have a strength class of C24 - Karl Hedin says that pressure-treated building studs are not classified as C24 but correspond to C24. So they are probably expressing the same thing differently.
But I interpret it as considering it C24.

/Göran

 

[Nygge72]

Beijer says that pressure-treated building lumber has a strength class of C24 - Karl Hedin says that pressure-treated building lumber is not classified as C24 but corresponds to C24. So they probably express themselves differently about the same thing.
But I interpret it as considering it as C24.

/Göran

Okay. Personally, I think pressure-treated feels much softer than regular wood. But it might just be a feeling.

 

[huggan]

As far as I know, printed C18.

 

[Sharky58]

This is what puzzles me:







Bauhaus, Beijer, and Woody - all claim "C24."

/Göran

 

[huggan]

Have they written it like that, but each rule is usually stamped. I've probably only seen 18 every time I've shopped.