Sitting here pondering how much screws/nails it takes to replace a joist hanger.
Reading JOMA's handbook on fittings.
From there, I gather that the design load-bearing capacity for a "standard joist hanger" 45x137, fully nailed with anchor nails (16 nails in bearing and 10 nails in the beam) is 7.34 kN (748kg) (according to the table, on 45x220 mm timber).
As I interpret it, it's the splitting of the beam that is dimensioning.
Looked up some data on nails and screws.
A 5" nail (125mm) that is 4mm thick seems to be rated at 1kN, i.e., about 102 kg.
This is in shear force, that is, perpendicular to the nail's length direction.
So to replace a joist hanger, one could use 7 5" nails to achieve approximately the same "load-bearing capacity." But how should one view this as there should also be pull-out when significant deflection occurs?
According to the wood guide's table on this concerning screws, an 8mm screw in 45mm wood is rated for 2.1 (214 kg) or 3 kN (306 kg), a bit unsure about the force parallel with or along the fibers.
So it would suffice with 3 8mm screws to replace a joist hanger.
A screw should also have much higher pull-out strength than a nail and perhaps thereby better than nails.
Could this be correct?
Am I thinking right?
If it is indeed the case that, say, 6 6mm screws can easily replace a joist hanger, why are joist hangers so popular? Why isn't toe-screwing used more?
Reading JOMA's handbook on fittings.
From there, I gather that the design load-bearing capacity for a "standard joist hanger" 45x137, fully nailed with anchor nails (16 nails in bearing and 10 nails in the beam) is 7.34 kN (748kg) (according to the table, on 45x220 mm timber).
As I interpret it, it's the splitting of the beam that is dimensioning.
Looked up some data on nails and screws.
A 5" nail (125mm) that is 4mm thick seems to be rated at 1kN, i.e., about 102 kg.
This is in shear force, that is, perpendicular to the nail's length direction.
So to replace a joist hanger, one could use 7 5" nails to achieve approximately the same "load-bearing capacity." But how should one view this as there should also be pull-out when significant deflection occurs?
According to the wood guide's table on this concerning screws, an 8mm screw in 45mm wood is rated for 2.1 (214 kg) or 3 kN (306 kg), a bit unsure about the force parallel with or along the fibers.
So it would suffice with 3 8mm screws to replace a joist hanger.
A screw should also have much higher pull-out strength than a nail and perhaps thereby better than nails.
Could this be correct?
Am I thinking right?
If it is indeed the case that, say, 6 6mm screws can easily replace a joist hanger, why are joist hangers so popular? Why isn't toe-screwing used more?
Oh, not even pears....
At some point, you should be able to reach the same strength with screws/nails as with a joist hanger?
The idea is that according to that handbook, the entire joint is good for 7.34 kN.
A nail joint is specified with a 5" nail to withstand 1 kN.
I don't see it as apples and oranges, I see it more as red and green apples?
Since 7.34 kN considers the properties of the wood, not just what the joist hanger can handle.
At some point, you should be able to reach the same strength with screws/nails as with a joist hanger?
The idea is that according to that handbook, the entire joint is good for 7.34 kN.
A nail joint is specified with a 5" nail to withstand 1 kN.
I don't see it as apples and oranges, I see it more as red and green apples?
Since 7.34 kN considers the properties of the wood, not just what the joist hanger can handle.
If you build a framework, meaning standing joists with an outer frame that you screw from the outside and then secure from the inside, you achieve better load-bearing capacity than if you use joist hangers. However, it requires that you can measure with a good fit for the finished framework, it must fit tightly against the surface it is screwed into, in all directions, or you can score an edge under the framework and lower it down, similar to laying subfloor panels but much larger in scale, then you can toe-nail if you feel like it! ^^
Yes, it is a floor structure that is assembled and then lifted into the building.
It is 45x220mm, three 5" nails from the frame into the short end of each beam.
Then screwed at an angle with 6x100 from the inside. 2 screws on each side of the beam.
Total per beam and short side is therefore three 5" nails and four 6x100 screws.
The frame is screwed into the outer wall studs (studs at cc60) with three 6x120 screws in each stud.
That’s why I’m trying to compare nails and screws against joist hangers, but wanted to try to keep it a little theoretical before introducing other assessments.
It is 45x220mm, three 5" nails from the frame into the short end of each beam.
Then screwed at an angle with 6x100 from the inside. 2 screws on each side of the beam.
Total per beam and short side is therefore three 5" nails and four 6x100 screws.
The frame is screwed into the outer wall studs (studs at cc60) with three 6x120 screws in each stud.
That’s why I’m trying to compare nails and screws against joist hangers, but wanted to try to keep it a little theoretical before introducing other assessments.