5" joists

[adrian.groves]

Hi,

I live in a Dormer bungalow built in 1939 and it has 5" joists supporting the upstairs floor. The bath is currently over an area where the joists span between two walls just 1metre apart and I want to move it to an area where the joists span 4.3m

The area in question has been part of the bathroom for around 30 years and there are no signs of sagging. (unlike me!)

Do you think I am worrying unduly about moving it?

Thanks
Adrian

 

[tony1851]

if you mean that the 5" joists are spanning 4.3m unsupported, it is unlikey to work with a bath, though not easy to follow your description.

 

[adrian.groves]

Thanks for getting back to me. just to help to be clear i have sketched the supporting walls and shown where the bath legs will be as 4 dots.

I hope this helps

 

[tony1851]

Assume the feet are 300 away from a supporting wall, right?
Most unlikely to be a problem - it will hardly increase the bending stress or deflection of the joists.
It will increase the shear stress in the joists at the bearing but - again - probably well within the shear capacity.

(Edit; A 5"x2" joist acting as part of a floor system will sustain a shear force of approx 300 kg - though remember that in addition to the weight of the bath, this also includes the weight of the part of the floor carried by the joist, and also the normal floor live load of around 30 lbs/sq ft.)

 

[adrian.groves]

Thanks Tony. I will make sure that I spread the load as well as I can.

I will investigate wether I can run a steel across the wall between the bath feet so it can help take the shear force.