ᐅ How should the rafters be installed in the ceiling?
Created on: 30 Sep 2009 17:50
S
SuperHorstS
SuperHorst30 Sep 2009 17:50Hello,
I would like to briefly introduce myself since this will be my first, and maybe not the last, post in this forum.
I’m from Rheinbach in Germany, near Bonn. I’m 41 years old and am currently renovating a half-timbered house. At the moment, all the ceilings are being removed because the ceiling height was too low and I’m quite tall. However, my question is mainly about the roof structure.
I want to install a walkable ceiling where later OSB floor panels, 22mm (7/8 inch) thick, will be laid and screwed down. The beams will either be placed in joist hangers or directly laid on the half-timbered frame on the right and left. The length of the beams will be about 4.5m (15 feet).
My question is: how thick should the squared timber or rafter wood be? For example, is a beam size of 15 x 15 cm (6 x 6 inches) or rafter timber of 8 x 16 cm (3 x 6 inches) or less adequate? What is the minimum thickness? The area is not meant to be a living space, only walkable. Or is there not much difference in beam sizing between a walkable and a living space in terms of structural design?
Thank you very much for your help.
I would like to briefly introduce myself since this will be my first, and maybe not the last, post in this forum.
I’m from Rheinbach in Germany, near Bonn. I’m 41 years old and am currently renovating a half-timbered house. At the moment, all the ceilings are being removed because the ceiling height was too low and I’m quite tall. However, my question is mainly about the roof structure.
I want to install a walkable ceiling where later OSB floor panels, 22mm (7/8 inch) thick, will be laid and screwed down. The beams will either be placed in joist hangers or directly laid on the half-timbered frame on the right and left. The length of the beams will be about 4.5m (15 feet).
My question is: how thick should the squared timber or rafter wood be? For example, is a beam size of 15 x 15 cm (6 x 6 inches) or rafter timber of 8 x 16 cm (3 x 6 inches) or less adequate? What is the minimum thickness? The area is not meant to be a living space, only walkable. Or is there not much difference in beam sizing between a walkable and a living space in terms of structural design?
Thank you very much for your help.
Are 22mm (0.87 inches) sufficient for a walkable ceiling? – It’s just an “attic floor.” The support spacing (meaning the number of joists) must be chosen accordingly.
Various suppliers of wooden beams / glued laminated beams offer online calculators for this.
If I remember correctly, we used 8 pieces of 240mm (9.45 inches) KVH (structural timber), but it could have been 10 pieces of 240mm (9.45 inches). (I only did the decking myself 🙂 )
For limiting deflection, the section modulus is important. A square cross-section doesn’t provide as much strength compared to a vertically oriented rectangular beam.
Various suppliers of wooden beams / glued laminated beams offer online calculators for this.
If I remember correctly, we used 8 pieces of 240mm (9.45 inches) KVH (structural timber), but it could have been 10 pieces of 240mm (9.45 inches). (I only did the decking myself 🙂 )
For limiting deflection, the section modulus is important. A square cross-section doesn’t provide as much strength compared to a vertically oriented rectangular beam.
@JOERG24
I am not concerned about the 22mm (7/8 inch) but rather the construction, as it is not habitable.
The rest involves structural engineering and needs to be calculated.
In the case of an old timber-framed house, it could also be collar beams, meaning an entirely different structural function would be involved.
Best regards
I am not concerned about the 22mm (7/8 inch) but rather the construction, as it is not habitable.
The rest involves structural engineering and needs to be calculated.
In the case of an old timber-framed house, it could also be collar beams, meaning an entirely different structural function would be involved.
Best regards
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