Bathroom joists

[Terry7556]

Bathroom joists have had a touch of modifying,are they beyond repair?
They are just under 7ins and the new notch is 35mm View media item 56946 View media item 56948 View media item 56949 View media item 56955 View media item 56950Both sides of the room have a notch for a pair of 15mm pipes and the room is 2.6mts wide

 

[tony1851]

You should be OK with those because the notches are at the end of the span. I would be more concerned if they were near the middle, where the bending stress is greatest.
At the end of the span, the only issue is shear stress across the joist, and that is not usually a consideration with domestic loadings.

 

[Terry7556]

Tony what about the weight of the bath,half full of water with an adult in it?
That's a reasonable amount of weight surely

 

[tony1851]

Tony what about the weight of the bath,half full of water with an adult in it?
That's a reasonable amount of weight surely

I agree it's a considerable weight, but let's consider the figures.

With the notches, his joists are effectively 50x140 at the bearing. Assuming C16 grade timber (which is usually the case), one joist of that size will take a shear force of about 3kN, which is roughly 660lbs.

Assume a worst case scenario with the bath directly against the wall and above the joist ends. There will be about five joists under the bath, so they will be able to take a combined shear load of 3300lbs, ie about 1 1/2 tons
(in practice it wil be about 10% more because you are allowed to increase the allowable stress when several joists work together).

Unless the bath is a huge Victorian cast-iron job and 3 or 4 people bath together(!) I doubt he'll have a problem.

 

[dann09]

AAMOI: do your pipes squeak and rub together when expanding and contracting? Perhaps a few pipe clips and straps to keep them from touching.

 

[Terry7556]

Will do dann,they are brand new at the moment,not connected to the system yet

 

[onecog]

I went to a leak recently where the pipe had expanded & contracted over many years and had worn away beacause someone had left a sunken nail in the joist.