There's a lot written but only about modern graded timber. My joists consist of approximately 100-year-old 150x150 beams, so why not measure deflection, reinforce, and measure again.
Is there a good way to do this? A "point load" in the middle of a beam is easy to set up, but measuring the deflection caused by this is trickier. Are there any good methods?
What I am thinking of doing is placing a leveling plate right across the room just above the beam with a few mm distance. Measure, place 100 kg right next to it, and measure again. Not entirely accurate of course, but if I measure x mm, it might be easier to decide on appropriate measures than to proceed with joinery, screw-gluing chipboard only to find that it still deflects too much... then it's "done for."
Is there a good way to do this? A "point load" in the middle of a beam is easy to set up, but measuring the deflection caused by this is trickier. Are there any good methods?
What I am thinking of doing is placing a leveling plate right across the room just above the beam with a few mm distance. Measure, place 100 kg right next to it, and measure again. Not entirely accurate of course, but if I measure x mm, it might be easier to decide on appropriate measures than to proceed with joinery, screw-gluing chipboard only to find that it still deflects too much... then it's "done for."
I would use a laser meter in the floor below. They measure with very high accuracy. Fix the laser meter, measure first without point load and then with point load. After that, you can compare with theoretical values for timber with different strength classes. When discussing deflection criteria in construction contexts, it refers to the instantaneous deflection that a point load causes.
Or hang a plumb in the ceiling above so that it hangs right over the floor. This way you can measure the play between the plumb and the floor after loading. But I would call it deflection rather than flex.
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Do you have a joist today that you need to address because it is sagging?
Unfortunately, I don't think your idea will help solve the sagging issue. However, one could calculate the current modulus of elasticity of the beams.
Unfortunately, I don't think your idea will help solve the sagging issue. However, one could calculate the current modulus of elasticity of the beams.
No, it corresponds most closely to 45x187, if 150 is the width and 125 is the height.
Yep, that's correct. And if I attach two 95s (one on each side), what will it be then? Anything I still need to do to align.
Then I guess your calculation is based on the assumption that the wood has the same strength, which we have no idea about...
Then I guess your calculation is based on the assumption that the wood has the same strength, which we have no idea about...
Yes, if you are going to compare the stiffness of two different dimensions, it presupposes that they have the same modulus of elasticity, otherwise, you need to recalculate the comparison numbers using the moduli of elasticity...
How do you want to place your 95
rs in height position? Otherwise, it would be a simpler calculation if you take 2 pcs of 125rs. Then the whole package corresponds to a 45x220.
How do you want to place your 95
rs in height position? Otherwise, it would be a simpler calculation if you take 2 pcs of 125rs. Then the whole package corresponds to a 45x220.Sure, I can just as well take 2 of the 125s.
It was precisely the difference in quality that made me want to measure. Guessing considering the type of timber in this house, it's not worse. Some logs are hardly able to take a screw while, for example, an anchor screw in a new c24regel can spin when it hits the bottom...
It was precisely the difference in quality that made me want to measure. Guessing considering the type of timber in this house, it's not worse. Some logs are hardly able to take a screw while, for example, an anchor screw in a new c24regel can spin when it hits the bottom...