Electrician has cut holes to close to joist ends

[JazzyB]

Hi

Employed electrician to wire extra sockets in bedrooms upstairs in an empty house. However I have noticed when I lifted floor board up to do other work, that the cables are running through holes close to ends of the joists, not within the safe zones, .25 & .4, as with Building Regs.

Looking for advise on how to approach this, with them.

Thanks
Jazz

 

[MJPD29]

I'd be highly doubtful it'll make any difference and probably a high chance that the majority if not all of the notches were already there.

 

[Mike Johnson]

How happy would any of you be if a Structural Engineer told you that the size of cable you specified is over the top and can be smaller.

OSG 7.3.1

 

[Grant1987]

How happy would any of you be if a Structural Engineer told you that the size of cable you specified is over the top and can be smaller.

OSG 7.3.1

Yes I appreciate that but drilling new holes surely would make matters worse wouldn’t it? I’m just counter debating ideally 50mm below top or bottom is perfect but using existing holes which have been used in millions of properties throughout the years doesn’t warrant non payment surely or classed as unsafe structurally

 

[Mike Johnson]

Did not mention non payment, just the fact there are specific place's where holes should be drilled or notches made.

 

[brianmoooore]

It's not a 'safe zone', it's a structural strength thing, and in most cases is absolute bo**ox, depending on how the end of the joist is supported
Nothing to do with separating pipes from cables either, since most pipes these days are fitted through drilled holes as well.

 

[Zerax]

The 0.25/0.4 thing is a one-size fits all thing... mainly directed at modern construction where everything is as small as it can possibly be. I agree with others on here... a 1970s built property will probably have substantially bigger timbers than a new build (excepting I beam cr@p). I've done alot of work in Victorian terraced houses, and they're even better built !... You could probably remove every other joist in those places and they'd still be stronger than a new build. I've also worked on really old places with solid oak joists that are as hard as granite !

So yes... there's Building Regs guidance... but we also need common sense. (if only it wasn't banned about 20 years ago !)

 

[Mike Johnson]

"One size fits all thing" so you know all about overturning moments, bending analysis and the way structural members fail by the twisting moment where compression and tension zones change or are at equilibrium, fascinating.

" I've done alot of work in Victorian terraced houses, and they're even better built !... You could probably remove every other joist in those places and they'd still be stronger than a new build. I've also worked on really old places with solid oak joists that are as hard as granite !" Do you know what joist are for?

 

[brianmoooore]

"One size fits all thing" so you know all about overturning moments, bending analysis and the way structural members fail by the twisting moment where compression and tension zones change or are at equilibrium, fascinating.

As it happens, I have studied these things, and passed the exams at the end, which is why I'm confident in saying that in most cases, especially with conventional timber joists, that the guidance is bo**oxs.

 

[Zerax]

"One size fits all thing" so you know all about overturning moments, bending analysis and the way structural members fail by the twisting moment where compression and tension zones change or are at equilibrium, fascinating.

It's been over 30 years since I did my degree in Mechanical Engineering ! I can hardly remember what I did yesterday !!

But I do remember having to use a 'safety factor' of 6 when we designed beams... which always annoyed me.

 

[mattg4321]

It's not a 'safe zone', it's a structural strength thing, and in most cases is absolute bo**ox, depending on how the end of the joist is supported
Nothing to do with separating pipes from cables either, since most pipes these days are fitted through drilled holes as well.

Correct, It’s not about separating pipes and cables. It’s about separating holes and notches.

 

[LukeD]

It was me who suggested holding back any final payment etc .Until we see how badly the new holes etc are .Its only fair to say it could either be minor or bloody dangerous .And it will not be hard to see if they are new holes or old etc . Ive seen terrible "Notching " and holes been done .That if the property belonged to me would annoy me .

 

[Teddy Lop]

I really wouldn't stress it, as said the guidelines are relatively recent (used to be just 1 in 6) and I've seen so many examples of far worse that never come to anything - typical one is lazy plumber can't be bothered to lift fresh boards so goes with a line of notches right over sparkys cable run, or removing 3" of joist for a waste.

 

[UNG]

But I do remember having to use a 'safety factor' of 6 when we designed beams... which always annoyed me.

That reminds me of one I had years ago when I rigged antennas, a structural engineer designed a bracket to fit to a building to take a 2.4M dish antenna, the bracket that was designed actually needed a bigger offset from the building than the structural engineer had allowed for so I asked him to revise the calcs for the extra 250mm offset and confirm this was acceptable his immediate answer was that it would not be a problem I pushed him to actually do the calcs and was told that even with the extra offset the bracket would still be at less than 10% of it's maximum load

 

[Grant1987]

It was me who suggested holding back any final payment etc .Until we see how badly the new holes etc are .Its only fair to say it could either be minor or bloody dangerous .And it will not be hard to see if they are new holes or old etc . Ive seen terrible "Notching " and holes been done .That if the property belonged to me would annoy me .

Fair enough mate I just don’t like it when customers come on here and then will use it against the electrician to not pay just by a single comment. They asked the person in question to carry out the work and therefore should trust his judgement I know there are plenty of cowboys but this particular thread seems like the electrician is being hard done by. Anyhow hope it all gets resolved and it’s not dangerous which I highly doubt.

 

[brianmoooore]

We are promised pics. next weekend, but so far we have been told that they are 25mm holes in 5 x 2, and near the end.
It's difficult to see how this could have any significant affect on the structural integrity of the joists, but I'll wait for the pics.