How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • Go back-and-forth until satisfied
    Rate the answer you receive.
Ask JamesI Your Own Question
JamesI, Developer
Category: Home Improvement
Satisfied Customers: 4940
Experience:  I have a portfolio of renovated houses, including DIY projects from installing bathrooms and new heating systems to rewiring.
Type Your Home Improvement Question Here...
JamesI is online now

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: 4 months ago.
Category: Home Improvement
Expert:  JamesI replied 4 months 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 4 months 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 4 months 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 4 months ago.

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

Expert:  JamesI replied 4 months ago.

I havent heard from you in some time please confirm if you need anything further or if your happy for me to close the question