Making service holes in 'cantilevered' part of joists

[Jdwood38]

Hi all,

Have searched for this and can't find the answer but probably not using the right terminology!

I'm aware of the various regulations about making holes/notches in joists, the number that you're allowed to do, size, distance from top/bottom/end etc. What I'm not clear of, is what, if any, are the regulations for any part of the joist that 'cantilevers' over the load bearing wall that the joists are sat on? Or, do the same regulations apply?

These are the types of joists in question. On the other side of this wall they span a room of c.3.5m wide and are bearing straight into an external cavity wall at the other end. We've got a whole load of pipes to run for heating renovation, ASHP etc and this would be an ideal route to follow. We could run in the "next" joist along (that runs perpendicular), but that would necessitate too many holes in a different joist elsewhere, so we want to "spread the load" as it were.

Hope that makes sense!

Thanks in advance for any advice.

 

[robinbanks]

If the joists you have circled are supported by the wall on the left of the picture (and another out of sight), and the joist that touches their ends is supported by the wall in the distance (and another behind the camera) then the circled areas wouldn't seem to be carrying any load. What is immediately above the floorboards that touch the joist parts circled?

 

[opps]

There are a number of sites that will explain what is permitted. eg

How to get it right: Notches & holes in solid timber joists | LABC

When installing pipework or cabling, floor or ceiling joists may need to be notched or drilled. But this could weaken the floor to such an extent that it becomes structurally unsound. To find out if this might be the case, you can find guidance on notches and holes in solid timber joists for use...

www.labc.co.uk

 

[Deleted member 174758]

I wouldn't say that is cantilevered, it's more of a change in joist direction and because of the way it is done the wall beneath it is probably load bearing (if it wasn't to start with it will become so over time!). So the standard rules apply, although because the joist connections are simply nailed and no joist hangers are used you shouldn't go too near to the intersection of the joists with your services if only because you could hit nails (probably been nailed with 3-1/2 to 4in nails). Ideally, rather than drill through so many joists it would be better to drill through one joist and bring the service through to where the other electrics run, run along there with the other wiring and if needs be take it back through the joist. Far less work