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Want to know from those who have done builds recent or are in the trade how interactions with Building control normally goes…
Scenario Building control called to look at structural steels, they raise a qry over the service holes drilled in a steel for central heating. Builder calls structural engineer who says it’s fine and has boarded over the steels ready for plastering
Is that it? Should there be some evidence other than phone calls given the structural engineer has said it’s fine? BC aren’t going to come back and ask to see it again are they?
Builder (and me) are taking lots of photos as we go.
First time doing a big build so probably worrying about nothing
What size holes and where are they positioned. There are basic rules for 1/3 points and depth of hole, 30mm IIRC but it will be a function of depth. If its a simply supported beam then at 1/3rd a small loss of section is fine as the beam is working hardest at midspan. Subject to loading etc.
I wouldn't worry about it 😉
3 x 22mm holes in a 5.5m steel. Builder said not to worry about it as well….but checked with engineer who said it was fine,
I’m sure it’s fine, I’m concerned with how building control works, and whether us saying “it’s fine” is enough for sign off or if they need more
Builder said control focused on that, and there were several other areas where he had gone above spec, they officer didn’t even look at.
It feels a bit random
if the engineer says its ok then its ok. Take photos as you're doing to show this and other critical stages then building control wont ask you to open anything up! They have to have a pretty good/robust justification to open up works!
You need to check with the BC officer concerned.
if the engineer says its ok then its ok
… but if the builder says that the engineer says that it’s ok, it might not be.
(“… oh, *those* holes…”)
BC will likely just need a statement from your engineer.
The size of holes seems okay, but it's the placement of them, mid depth at third points no worries. Three 22mm holes lined up vertically mid span of a 152UB, less so.
Assuming the holes are in the web (the vertical part) they will be of no consequence at all unless you have very unusual loading, and if the building inspector wants to push it I would ask them to talk to the engineer directly. I seriously doubt their competence for even having raised the question.
If its a simply supported beam then at 1/3rd a small loss of section is fine as the beam is working hardest at midspan.
Assuming, again, that the holes are in the web, they would affect the shear capacity, not the bending capacity. Supports are where the beam works in shear, midspan is only relevant to bending. On a 5.5m span in a domestic application, shear is very unlikely to be crucial.
I am a structural engineer.
Chill.
get anything like this in writing. even just an quick email will do. just to cover your arse.
Standard hole size for a M20 bolt. I wouldn't think twice about it. I would only want a note from the engineer if I was putting in 40mm dia +
I assume your builder would have used common sense and put them horizontally rather than vertically.
Sounds like your BC is one of these who thinks he knows more than he actually does 😉
I think the concern was one of the holes was close to the end about a foot from the padstone
All holes are in the web.
And this is one of 9 (!) steels - 8 of which are all in a sort of "H" shape holding up the rooms above. So there is alot of steelwork all supporting each other.
Other qry was around welding joints instead of just bolting. Engineer confirmed welding was fine, and didn't spec it as many builders don't want to weld onsite
Other qry was around welding joints instead of just bolting. Engineer confirmed welding was fine, and didn’t spec it as many builders don’t want to weld onsite
Might just be trying to circumvent BS EN 1090-1 EXC 2 *
If you weld end plates etc on in the workshop, then you should have this certification to be able to sell fabricated steelwork (legally). It is a conformance system. There is a factory production control system to make sure you have the correct weld procedures and your welders are tested etc. It also covers materials. Fabricator should have a paper trail if anyone involved in the job wants to see it.
Welding on site should be done by a certified welder, not Dave from down the pub. Sounds like your BC would have picked up obvious shitty welding, but unless he/she knows exactly what they are looking for then you can never be 100%. Did you engage the fabricator yourself in the end or has the builder supplied the frame ?
* most small fabricators have no idea what these letters even mean.
All though the system is not exactly policed. Other than when something goes wrong and the paper trail starts.
Engineer trumps bc
On the flip side.... My SE wanted some proper OTT reinforcing of some existing beams - my builder thought it was not required and suggested something simpler.
BC agreed with the builder and I ignored the SE!
End if the day your certificate comes from BC and not the SE.
BC agreed with the builder and I ignored the SE!
Obviously not seen what the SE suggested, but unless they have agreed to the new proposal , surely you are not covered under their insurance if it went tits up
Obviously not seen what the SE suggested, but unless they have agreed to the new proposal
They did see what the SE wanted and what the builder suggested.... Went with the latter.
(It was actually reinforcement of existing beams that were once BR compliant.
BR inspector suggested that the SE was being overzealous)
I guess that’s fine if you are covered by the builders insurance . I have had some monsters from SE in the past , but ultimately if i deviated from their design then I wouldn’t be covered under their Pi.
the guy doing the welding onsite was the same guy that supplied all the steels. builder uses him on all his jobs. can't say I checked his paperwork though. but if he making steels to order I would expect him to be legit and not Dave from down the pub! all looked pretty clean to my non expert eye. I took photos!
is there somewhere you can see the key inspection points for BC? the builder is managing it, but I'd still like to make sure it's done
is there somewhere you can see the key inspection points for BC
Not easily. The legal requirement is to comply with the Building Regulations, which in effect say you have to show it won't fall down. The usual way to do that, and the way BC will expect, will be to design it to meet the requirements in Approved Document A, which you can download from the Planning Portal. However, it refers out to various BS and EN standards, which are not available unless you buy them, and not cheap. You don't in theory have to follow the AD, you can meet the legal requirement in other ways, but in practice it's impossible to convince BC other than using the AD. But you don't need to worry about that, that's why you employ an engineer.
Your 9 beams are a bit more complex than I thought, I was under the impression it was a single span when I made my comments above. So there might be a point where shear force is more significant.