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JamesI
JamesI, Developer
Category: Home Improvement
Satisfied Customers: 4209
Experience:  I have a portfolio of renovated houses, including DIY projects from installing bathrooms and new heating systems to rewiring.
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I'm trying to reroute a waste pipe under the floor. The

Customer Question

Hi, I'm trying to reroute a waste pipe under the floor. The joists run in the correct direction but there is a double joist running perpendicular to these and parallel to the external wall that appears to be supporting the joists by means of joist hangers. My question is can I cut a 45mm hole in the supporting joist (220mm) without affecting the integrity of the structure?
Submitted: 12 days ago.
Category: Home Improvement
Expert:  JamesI replied 12 days ago.

Hi, thank you for choosing Just Answer, my name is ***** ***** I will help with your query today.

Is it just one hole you need for the waste?

Customer: replied 11 days ago.
HI James. I need to run a basin waste as well but was planning on joining these before feeding through the joist
Expert:  JamesI replied 11 days ago.

The maximum hole you can cut is 25% of the hole so I make what your plan to drill 21% so its on the large side but sufficient, however the hole must be in the middle of the joist and you should avoid having more than one hole, the diagram here probably explains it better.

If you can avoid a secondary hole that would be ideal, so would get that joined prior to going through the joist as you suggest.

Expert:  JamesI replied 9 days ago.

Please confirm if I can close the case or if you require any further assistance.