bonding structural steel buried within fabric of building

[ExArmy]

was in a half finished house today that has just had an extension built on it, and i was suprised to see 10mm bonding to the steel RSJs that span the garage and where the kitchen has been knocked through and at the front where a porch has been created. traced them back to the MET, have all been labelled up "extraneous steel work"
they have been boarded and will be plastered when finished so they won't be exposed, is it really necessary to do this. I think not but i though i would mention it here see what you guys think

 

[Amp David]

If it ain't exposed when fishished then why bond?


Plenty of posts regarding this

 

[GLENNSPARK]

If it ain't exposed when fishished then why bond?


Plenty of posts regarding this

and what if someone decides to get the drill out?.......

 

[ExArmy]

and what if someone decides to get the drill out?.......

and do what?

if this is required (doubtful) then whats next, bonding each 225mm cavity tie inside the cavitys, bonding the backstraps that hold the wall plate down? where will it stop. bonding each individual nail and screw incase "someone gets the drill out"

 

[GLENNSPARK]

and do what?

if this is required (doubtful) then whats next, bonding each 225mm cavity tie inside the cavitys, bonding the backstraps that hold the wall plate down? where will it stop. bonding each individual nail and screw incase "someone gets the drill out"

well someone saw fit to do it.....so on that basis be thankful.....

 

[Engineer54]

Any structural steelwork, that forms a part of or fully the structure of the building, that is tied in to the re-bar of the foundations Should Always be bonded back to the MET of the incoming supply. Even if it's not actually exposed to touch, which can't always be guaranteed during the life of building, it will improve your installations Zs!! lol!!!

 

[Engineer54]

and do what?

if this is required (doubtful) then whats next, bonding each 225mm cavity tie inside the cavitys, bonding the backstraps that hold the wall plate down? where will it stop. bonding each individual nail and screw incase "someone gets the drill out"

Now your just being Silly!!! Structural steelwork is just a little different to a cavity wall tie now isn't it?? ....lol!!!

 

[Amp David]

Does tied mean sat on a motar bed withing a brick or block wall?

 

[Engineer54]

You don't sit structural steelwork on mortar beds mate, they are normally set in, or bolted to reinforced foundations!! ...If your unsure if it is extraneous, then you can always test it, but it's a mistake to ignore it!!!

 

[GLENNSPARK]

415.2.1 brb...

 

[Amp David]

So how many houses have structural steels bolted to the ground?

I( know structural steel is bolted or set into foundations, but from the description of the op i took it as a steel forming a lintel.

 

[Andy 7671]

Any structural steelwork, that forms a part of or fully the structure of the building, that is tied in to the re-bar of the foundations Should Always be bonded back to the MET of the incoming supply. Even if it's not actually exposed to touch, which can't always be guaranteed during the life of building, it will improve your installations Zs!! lol!!!

MET of incomer, sorry, Im not getting this. Do you mean the 11kv/400 spur or the earth bar in switch room.

Ive seen structural steel bonded to earth mat/tape before but havent noticed it going to switch room.

Just asking to expand knowledge.

 

[Amp David]

How have we gone from 11kw to a domestic kitchen?

Keep a control of it boys!

 

[Engineer54]

MET of incomer, sorry, Im not getting this. Do you mean the 11kv/400 spur or the earth bar in switch room.

Ive seen structural steel bonded to earth mat/tape before but havent noticed it going to switch room.

Just asking to expand knowledge.

Errr, i think were talking about a domestic installation here!! ...lol!!

But, if we were talking about a 11 KV distribution substation, then it would be bonded to the LV main earth bar (MET), not the MV earthing system bar(s)...

 

[Andy 7671]

Oh jeez, sorry for hijack, just let my minds eye wonder from post no 6, many thanks, sorry again for hijack....goes and stands in corner feeling sheepish.

 

[Amp David]

And so you should!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[ExArmy]

Any structural steelwork, that forms a part of or fully the structure of the building, that is tied in to the re-bar of the foundations Should Always be bonded back to the MET of the incoming supply. Even if it's not actually exposed to touch, which can't always be guaranteed during the life of building, it will improve your installations Zs!! lol!!!

none of the steel RSJs are in any way tied to the re bar in the foundations, and, there isn't any re bar in the foundations in this particular house
the steel RSJs are infact just mortar bedded onto concrete padstones thats were built into the walls, so they will not help the ZS in any way.

You don't sit structural steelwork on mortar beds mate, they are normally set in, or bolted to reinforced foundations!! ...If your unsure if it is extraneous, then you can always test it, but it's a mistake to ignore it!!!

maybe in commercial or industry, but in domestic dwellings it is common to mortar bed steels onto concrete padstones (normally a 6X4 dense concrete lintel chopped into 300mm lenghts)
maybe sometimes if it needs it vertical steels are put in place to support along the length or instead of block pillars, but then they would only go down as far as damp course level and would be bolted to about a metre of concrete, so they would not really alter the ZS as they dont go into the ground
theres certainlly not going to be any tying in to the re-bar in a domestic dwelling founds, for a start re bar in domestic founds is quite rare, and secondly most steels are additions anyway. and even in new builds i've never seen it.

 

[Engineer54]

You need to read my posts above, i didn't say your situation was tied in to the foundation reinforcement. You gave very little information, i was pointing out where and when situations!! What's a lintels and concrete pads, it certainly isn't a mortar bed is it?? If you knew how these RSJ's were installed, why didn't you mention it in the first place??

As for your comment on not using reinforced foundations in the UK for housing, i'm afraid you would be wrong, in many instances that would be the only course of achieving a stable base for a building. I know of many areas where housing estates are All built on reinforced foundations. It all very much depends on the the ground your building on!!

So, ....Did you test these RSJ's before dismissing them, as not being extraneous??

 

[Amp David]

Concrete raft foundations, usually done in sandy areas i think.

 

[ExArmy]

You need to read my posts above, i didn't say your situation was tied in to the foundation reinforcement. You gave very little information, i was pointing out where and when situations!! What's a lintels and concrete pads, it certainly isn't a mortar bed is it?? If you knew how these RSJ's were installed, why didn't you mention it in the first place??

a concrete lintel is used to go over the top of windows and doorways. normally 6" X 4" and upto about 4M in length. if openings are larger than 4m then RSJs are normally used, depending on the load above to be supported. pic

reason i mentioned lintels is steel RSJ's have to be sat on a pad stone of some sort (building regs).
when structural steels are added, the wall that they sit on will not always be strong enough to support it on its own. the concrete padstone helps distribute the load, and normally 300mm is all that required. but it does depend on what the walls are built out of for example, thermalite block walls would maybe need a larger pad or else the weight would just smash through them and the whole thing would fall down, and concrete blocks would not need as bigger padstone if any really, but they are always put in anyway

and yes, they are mortar bedded onto these padstones that are built into the wall.

As for your comment on not using reinforced foundations in the UK for housing, i'm afraid you would be wrong, in many instances that would be the only course of achieving a stable base for a building. I know of many areas where housing estates are All built on reinforced foundations. It all very much depends on the the ground your building on!!

never seen re-inforced foundations electrically connected to the MET though, which is the point i was getting at.

So, ....Did you test these RSJ's before dismissing them, as not being extraneous??

never tested them because literally everything in the house is bonded together and it is all boarded out , would have to rip it to peices to disconnect it all to test