Skip to main content

Ready to hire?

Post your job in minutes, browse real reviews and choose who to speak to.Post a job

Need some tips or advice?

Ask a question
Plumbing

Is the depth of the joist notch too deep?

Anonymous user 16/03/2024 - 2.37 PM

I am having a new bathroom fitted. They are currently doing the plumbing work and made a cut in many of the notches for the hot/cold water pipes and waste pipe. The cuts seemed quite deep (half of the depth of the joists) and I felt it could weaken the structure of the floor. I checked online and read the notch should never be greater than 1/8 of the depth of the joists. 1) are the notch too deep and against regulations? 2) If they are, what are my options? Should I stop all work? Can the notch be repaired or strengthen? Knowing this is our only bathroom, any set back means extra days/weeks without a shower, which isn't ideal.

Are you a tradesperson and able to answer this question?

Log in

1 Answer

Anonymous user

For notches, Maximum depth = 0.125 x joist depth Safe zone = between 0.07 and 0.25 the span For holes, Maximum diameter = 0.25 x joist depth Safe Zone = hole centre line between 0.25 and 0.4 of span Holes in the same joist should be at least 3 diameters apart. Obviously these are just rules of thumb, there are still many other factors that may mean even when following the above, it would not be safe to do so. https://www.labc.co.uk/news/how-get-it-right-notches-holes-solid-timber-joists They should also be putting steel plates over any services going through a notch. https://www.toolstation.com/safe-plate/p20903?store=N1&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&gclid=EAIaIQobChMIgoqL5fuk7QIV1e3tCh3L1gSMEAQYAiABEgLUdfD_BwE If you are worried, ask them to stop and get a carpenter to check it out. Tradesmen need supervision, in a more commercial line of work, they would have someone with a degree keeping them under control. Baths can be very heavy when full, they are placed near to walls because joists struggle to hold them without notches.
Answered28 November 2020
2