dangti6 Posted August 13, 2020 Share Posted August 13, 2020 I'm not even out of the ground yet, but it feels like this thing has been built several times over in my head. Essentially I am trying to be several steps ahead of myself to ensure things can run as smoothly as possible. I am looking at having a beam calculated in advance of the walls going up, and want to make sure I have enough info/detail to make it clear to others what I am trying to achieve - especially if there's no site survey, they could misenturpete my requirement. Project is a 100mm single skin, single garage which is to be extended width ways to a large double with a 16ft door opening. Beam length approx 5100mm (4800 + 150mm each end) so off the shelf catnics and similar become cost prohibitive. One pier of the new opening falls within the existing opening so this opening will be paritally bricked up to in effect move the opening over. Currently, externally there is a single course of facing brick on top of the steel strip attached to the catnic lintel. I am looking to render the outside of this garage when complete, so my intention is to have a steel beam with a plate welded to the bottom to take it out to ~215mm in width to sit on the piers and allow a course of brick to run flush along the front of it which can be rendered over. Would others recommend this approach or try to hide the beam up behind the fascia? The wall that will be built within the existing door opening will replace the old catnic or sit under it. Footings will be dug to the same depth as other trenches - I am under the impression this footing doesn't need to be calculated. Reason being, I am not showing any calculations for the rear wall which will also hold the roof and assume the depth check to solid ground in advance of pouring the concrete would suffice here? For Building Control, I am doing this under a notice rather than full plans. Would I require more than just a beam calcuation to satisfy building control for this lintel? Will they require additional Building Regulation drawings that I don't currently have? I guess what I am trying to avoid is having a calcuation that doesn't satisfy the BCO, or paying more than neccesary obtaining drawings that aren't neccesary. Attached images should hopefully help visualise. Link to comment Share on other sites More sharing options...
Temp Posted August 13, 2020 Share Posted August 13, 2020 This has to have been done lots of times. Google found... https://www.diynot.com/diy/threads/double-garage-lintel-spec.151818/ Just had this done - replaced a 5.1m 100x200mm wood beam, central pier/pillar and two single up and over doors with an RSJ and full width roller shutter door. RSJ spec was calculated by an SE as needing to be 203x203x60 sitting on padstones. Might be over-specified but should hold the roof up! Link to comment Share on other sites More sharing options...
dangti6 Posted August 13, 2020 Author Share Posted August 13, 2020 Thanks for your comment Temp. Funnily enough I came across that very thread when I was looking at what size people were using to do my costings. No doubt you know a lot more than me, but is this not very much like an exam question - need to show your workings to show how you got to the answer? If it is a case of over specifying something proven to be more than suitable of taking much more than my load, I’d be happy to go down that route. Link to comment Share on other sites More sharing options...
Temp Posted August 13, 2020 Share Posted August 13, 2020 You could try proposing a size to the BCO and see what he says. He might recognise it as being reasonable or he might ask for you to justify the size, in which case you would need calculations done. Link to comment Share on other sites More sharing options...
PeterW Posted August 13, 2020 Share Posted August 13, 2020 You can get a simple steel calc done online for about £40 - peace of mind doesn’t normally come that cheap ! 1 Link to comment Share on other sites More sharing options...
dangti6 Posted December 3, 2020 Author Share Posted December 3, 2020 BCO required something for the file. Calculations suggest I need to go for either of the following 254x146x43 Universal Beam or 250x150x5 Rectangle Hollow Section I’m swayed to the UB - are there any benefits to a RHS that I am unaware of? Link to comment Share on other sites More sharing options...
PeterW Posted December 3, 2020 Share Posted December 3, 2020 UB is cheaper and easier to get hold of. Link to comment Share on other sites More sharing options...
dangti6 Posted December 3, 2020 Author Share Posted December 3, 2020 (edited) The difference in price I have been getting for a UB is quite staggering. 5200mm in length and primed. Cheapest quote I have had is £339 and the most expensive was £792 (both inc vat, delivered). May ask the cheaper supplier what the RHS price is just to satisfy my curiosity Edited December 3, 2020 by dangti6 Link to comment Share on other sites More sharing options...
Jason L Posted December 3, 2020 Share Posted December 3, 2020 The UB may be best as it will be easier to bolt a wall plate on top of it. Link to comment Share on other sites More sharing options...
wozza Posted December 3, 2020 Share Posted December 3, 2020 I got one of my steels from a local Steel Stockholder - way cheaper than the local fabricators quoted, just had to paint it myself. Link to comment Share on other sites More sharing options...
dangti6 Posted December 3, 2020 Author Share Posted December 3, 2020 31 minutes ago, Jason L said: The UB may be best as it will be easier to bolt a wall plate on top of it. Intention was to attach the wall plate with self drilling screws. Saw mention of this online assuming that still meets regs? Link to comment Share on other sites More sharing options...
Jason L Posted December 3, 2020 Share Posted December 3, 2020 13 minutes ago, dangti6 said: Intention was to attach the wall plate with self drilling screws. Saw mention of this online assuming that still meets regs? I wouldn’t know if that will work, all I can say is, that on all the engineers details that I have seen it’s always bolted to the beam, someone may be able to confirm. Link to comment Share on other sites More sharing options...
Adam2 Posted December 5, 2020 Share Posted December 5, 2020 If using box section you could look at blind bolts Link to comment Share on other sites More sharing options...
dangti6 Posted December 10, 2020 Author Share Posted December 10, 2020 Local merchant comes up trumps once again. £288 all in for the 254 UB. Link to comment Share on other sites More sharing options...
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