As a happy amateur (engineer but not construction...) I need help with a reality check on a planned deck build.
- Large deck: 8.2 x 13.6 meters
- On posts and pilings (sloping lot)
- Beam spacing: 1800mm
- Overhang about 400mm
- Pilings spacing: 1600mm
- Floor joist spacing: 600mm
I have calculated 45x195 C24 as beams and 45x170 C24 as floor joists.
The decking will be 34x145 kärntrall.
With the programs I have found online and a simple deflection formula for beams, I can't help but understand that the intended dimensions should be more than sufficient.
(If I calculated correctly, a point load of 2kN in the middle of supports yields a deflection of 1.2mm)
I don't want to take chances and would rather build with over-dimensioning, and the goal is a rigid deck.
Comments? Surely the dimensions are sufficient, right? Or is it completely overdone with safety margins?
/Göran
- Large deck: 8.2 x 13.6 meters
- On posts and pilings (sloping lot)
- Beam spacing: 1800mm
- Overhang about 400mm
- Pilings spacing: 1600mm
- Floor joist spacing: 600mm
I have calculated 45x195 C24 as beams and 45x170 C24 as floor joists.
The decking will be 34x145 kärntrall.
With the programs I have found online and a simple deflection formula for beams, I can't help but understand that the intended dimensions should be more than sufficient.
(If I calculated correctly, a point load of 2kN in the middle of supports yields a deflection of 1.2mm)
I don't want to take chances and would rather build with over-dimensioning, and the goal is a rigid deck.
Comments? Surely the dimensions are sufficient, right? Or is it completely overdone with safety margins?
/Göran
There is nothing wrong with having margins when it comes to outdoor constructions. The damp environment degrades the stiffness of timber over time. I get the same result on the deflection with your conditions. You need to keep an eye on the shear forces when it comes to beams in general. You manage it with a decent margin thanks to small c/c distances between posts and beams.
34x145 mm decking provides superior rigidity!
34x145 mm decking provides superior rigidity!