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

 

[LukeD]

Get back , show regs, ask them to make good (strap joists with extra timber ?) .Dont pay any balance until done.

 

[buzzlightyear]

What type property is it new, old..and what depth is the joists.

 

[JazzyB]

Get back , show regs, ask them to make good (strap joists with extra timber ?) .Dont pay any balance until done.

Thanks will do, was quite shocked when I saw what they had done, at the time so didn’t now about the regs, but it just looked wrong. It was then I checked on the rules about cutting holes in joists.

 

[buzzlightyear]

Thanks will do, was quite shocked when I saw what they had done, at the time so didn’t now about the regs, but it just looked wrong. It was then I checked on the rules about cutting holes in

How big is the holes and pic would be nice.

 

[JazzyB]

What type property is it new, old..and what depth is the joists.

It’s 1970’s detached house, without measuring the joists for sure I would guess they are about 50 x 122.

 

[SJD]

I would check are these new holes incorrectly cut, or were they existing? If existing holes, then the electrician has done nothing wrong in using them.

 

[Dustydazzler]

In the old days I always used to drill my holes about 300mm from the wall, did it this way for many many years. Then someone pointed out the .25/4 rule so I now come in roughly .25 the span

 

[JazzyB]

How big is the holes and pic would be nice.

Holes are about 25mm, will be back at property next weekend so will post some pictures then.

 

[JazzyB]

I would check are these new holes incorrectly cut, or were they existing? If existing holes, then the electrician has done nothing wrong in using them.

 

[JazzyB]

Definitely new holes, as existing cables run further back from the joist ends.

 

[SJD]

Definitely new holes, as existing cables run further back from the joist ends.

I would check for recent sawdust debris. I often come across existing holes in older properties e.g. from removed pipework, or even once in a while a whole line of pre-drilled holes that didn't get used (nice to find, sometimes).

 

[mattg4321]

The position of the holes will be fine as long as there are no other sections of the same part of the joist removed. Ie notches in the same area of the joist.

The regs are only as they are to give a clear zone for notches and for holes so there is no confusion between plumber/electrician.

Holes always used to be drilled nearer the walls as dusty says.

Sometimes it’s not practical to take up the part of the floor that is over the ‘correct’ section of the joist. It’s often not possible to see the span of the joist until you have access either. Your electrician has potentially done nothing wrong imo.

 

[telectrix]

as above. as the joists are c.1970, they will not be flimsy oven baked crappy wood like today's builds and will not collapse when farted on with > 1Nm of metric force per ssquare centipede when the ambient temperature is outside the range 20 -21deg. and the humidity is above 60%.

 

[Grant1987]

The position of the holes will be fine as long as there are no other sections of the same part of the joist removed. Ie notches in the same area of the joist.

The regs are only as they are to give a clear zone for notches and for holes so there is no confusion between plumber/electrician.

Holes always used to be drilled nearer the walls as dusty says.

Sometimes it’s not practical to take up the part of the floor that is over the ‘correct’ section of the joist. It’s often not possible to see the span of the joist until you have access either. Your electrician has potentially done nothing wrong imo.

I agree I would feel hard done by if one of my customers had lifted floorboards and inspecting my routing of cables. I would/Do use existing holes where necessary although I tend to stick to the rule of thumb of 50mm from top or bottom of joist but I certainly don’t stress over routing my cables on existing holes. Not sure who said on here on not paying the spark but that’s ridiculous. Are there any other issues or is it just the routing that your not happy with?

 

[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.

 

[Mike Johnson]

Near the end at the point or near the point of maximum shear, I too will look forward to the pictures.

 

[JazzyB]

Here are the photos as promised, I’am ok with it as long as it not going to cause me problems in the future.

 

[suffolkspark]

Here are the photos as promised, I’am ok with it as long as it not going to cause me problems in the future.

Did he run the tv cable in too?

 

[JazzyB]

Did he run the tv cable in too?

Yes

 

[Jim_e_Jib]

If that was new work in my house, like you, I wouldn't be happy.

There doesn't appear to be a reason for not putting the holes in the prescribed zones and, unless more cables are to be added, the holes appear to be larger than they need to be.

Was the same electrician responsible for the hole bottom left in the 2nd picture?

As I think Littlespark is alluding to, it's not good practice to run a signal cable such as coax so close to LV power cables.

All that being said, my house (Victorian era) has had many of the joists butchered over the years. Notches and holes out of prescribed zones and often very close together. Holes drilled at a 45 degree angle through the timber. The previous owner took a huge chunk out of a joist under the bathroom as they positioned the shower tray such that the waste outlet was on a joist. So far, the floors are still standing...!

 

[SJD]

The holes do look ridiculously large for the cables, as if the electrician only had one size of drill bit and it was big.

No, wait, big pipe-sized holes whereever convenient, ... are you sure this guy is not a really a plumber?

 

[JazzyB]

If that was new work in my house, like you, I wouldn't be happy.

There doesn't appear to be a reason for not putting the holes in the prescribed zones and, unless more cables are to be added, the holes appear to be larger than they need to be.

Was the same electrician responsible for the hole bottom left in the 2nd picture?

As I think Littlespark is alluding to, it's not good practice to run a signal cable such as coax so close to LV power cables.

All that being said, my house (Victorian era) has had many of the joists butchered over the years. Notches and holes out of prescribed zones and often very close together. Holes drilled at a 45 degree angle through the timber. The previous owner took a huge chunk out of a joist under the bathroom as they positioned the shower tray such that the waste outlet was on a joist. So far, the floors are still standing...!I

 

[GBDamo]

The problem with deviating from guidance is you then have to qualify your choices.

We all know that there is an --- Cover Factor in many regs but if we venture there the onus is on us to demonstrate we have not introduced a hazard.

In solid, dry and rot free joists, like those, I can guarantee those holes will no be an issue but I cannot qualify that statement.

All I can offer is if it were my house I wouldn't be worrying.

 

[Mike Johnson]

As the electrician has deviated from the prescribed zones ask for his Hazard Analysis and Risk Assessment, that he obviously did, to satisfy himself that it was OK to do so.

 

[Pretty Mouth]

As the electrician has deviated from the prescribed zones ask for his Hazard Analysis and Risk Assessment, that he obviously did, to satisfy himself that it was OK to do so.

Come off it Mike. Everyone here, including yourself, knows those joists aren't going to collapse.

To the OP: Of all the sins an electrician can commit, this is about as minor as it gets. Put the floorboards back down, and don't worry about it.

 

[Mike Johnson]

The analysis carried out by a qualified Structural Engineer that qualified the zones specified where established for a reason, taking into account the compression and tension zones within the timber and the shear zones at the bearing end, a Structural Engineer would not dream of telling an Electrician how to do his job.....................................

 

[telectrix]

them joists will still be supporting the floor long after today's new builds have been bulldozed into landfills.

 

[mattg4321]

Where’s the eye roll emoji

 

[MJPD29]

I dont think that will ever cause any structural damage to the joist. It'll be absolutely fine I've seen it in many many places and it's never caused an issue. Just put the floorboards down and don't worry about it.

 

[Pretty Mouth]

The analysis carried out by a qualified Structural Engineer that qualified the zones specified where established for a reason, taking into account the compression and tension zones within the timber and the shear zones at the bearing end, a Structural Engineer would not dream of telling an Electrician how to do his job.....................................

I am literally holding my head in my hands reading this

 

[UNG]

The analysis carried out by a qualified Structural Engineer that qualified the zones specified where established for a reason, taking into account the compression and tension zones within the timber and the shear zones at the bearing end, a Structural Engineer would not dream of telling an Electrician how to do his job.....................................

For structural engineer read overkill merchant over the years the ones I've come across have such a high overhead on their calcs the likelyhood of anything happening even in an earthquake is minimal

 

[GBDamo]

The analysis carried out by a qualified Structural Engineer that qualified the zones specified where established for a reason, taking into account the compression and tension zones within the timber and the shear zones at the bearing end, a Structural Engineer would not dream of telling an Electrician how to do his job.....................................

Id argue the reason was to prescribe a place where notches should be made rather than to say where holes couldn't be made.

 

[LukeD]

Is there not another set of holes about 2 inches further into the joists ? Looks like there are