If there is no major weight on the joists,then I wouldnt worry.BUT if your installing a bath on the joists then you need to brace the joists.Use the same size joist 200mm x 50mm by 1m in length then fix it to the original joist over the holes with 4 x 10mm thick bolts and dog washers.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!