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Hi All, How much should I be paying for the standard priming of fabricated steel RSJ sections please. A price per tonne would help? Thanks

Good afternoon everyone, I hope you are enjoying the bank holiday weekend! I'm new here, I've had a look around and I can't see a topic on the issue I have (which I guess is a good thing!). There is a bit of a backstory here so please do bear with me. I moved into my house coming up to 4 years ago, there was a wall in the kitchen that didn't make much sense in being there so I spoke with a (former) friend who I knew as a builder, he came round and had a look and noticed that above one of the walls I wanted to remove, there had been 3 (partly) replaced joists that were held together with a few wood screws, he advised me that I needed to put 2 x 12mm coach bolts through each them and then I'll be ok to remove the wall below. So that's what me and my old man did one weekend, there was a pillar which was part of an old wall which I left in as I liked it as a feature, (this was 3 years ago) the wall got removed bit by bit with no issues. Fast forward to last week (W/B 25/04/22), I want to remove the pillar now to fully open up the kitchen and the remaining wall that formed a breakfast bar. I wanted to get a builder in to confirm that I was able to remove the pillar with no issues and that's when everything seemed to snowball! I spoke to one builder (Monday, last week) and he asked me to send over some pictures and he'll let me know when he would be able to get out to have a look. Tuesday afternoon rolls around and I get a phone call saying he thinks I'll need a structural engineer, he gave me the number of a mate of his, I then spoke with him, he thinks I'll need an RSJ, I want to avoid this where possible as it'll have to be a 7m to reach side to side of my kitchen. I've been Googling (as you do to try and learn about the issue) and found that I might be able to replace the joists as the span is 3200mm (ish) using C24 47x175mm timber, I spoke to the structural engineer and he seems adamant that I'll need an RSJ (he hasn't been around to look yet) I looked at the average price of a 5m RSJ supplied and fitted and it seems to be just over £1k, not something I was expecting and not something I can “just pay for” either. So, after all that, my question is, can I not just replace the joists so that they sit wall to wall? I understand it’s a floor boards up, wiring out and ceiling down etc but I’d prefer to do that than have a 7m RSJ in my kitchen. I put the acro's in as a "just in case" it's been fine for the last 3 years. Any advice is much appreciated

For long spans the loading can rise considerably. Not only does the load rise in proportion to length, the resulting peak moment on the resisting member rises with the square of length: The section of the member needs to get increasingly large to resist the increased moment and still the designers typically allow a deflection in proportion to length. As I understand it, this is typically L/325. That means that a lintel for a 3300mm opening will allow a 10mm deflection at the limit. Cavity lintels for large spans (e.g. >2400mm) start to become very expensive if there are roof or floor loads near by. For example, a 3750mm lintel with a total UDL capacity of 50kN runs to around £200-£400. Steel beams have huge moment resisting capability depending on their section. There is a range of Universal Beams (aka RSJ) which have a width of 102mm well suited to a 100mm internal leaf. A 3800mm 305x102x25kg beam costs around £200. I want to understand when to swap to such a steel. Considering just universal beams for a 3400mm opening with 50kN UDL: Section Iy(cm4) Deflection Saving 178x102x19kg 1356 L/364 (9.3mm) 22% 203x102x23kg 2105 L/564 (6.0mm) 6% 305x102x25kg 4455 L/1200 (2.8mm) 0% NOTE: 254x102 UB omitted A cavity lintel would probably have a deflection of 10.5mm (L/325). Steel beam advantages: reduced deflection, greater capacity, lower cost Steel beam disadvantage: rarely galvanised and so needs careful painting etc when exposed to cavity, needs boxing in for fire protection Cavity Lintel advantages: galvanised, makes provision for outer leaf, stated capacity so no need for Structural Engineer's input Ease of installation can go both ways. At length, both are heavy. What experience do people have and when do they typically change from cavity lintels to steel beams?

Good morning all. We're doing a stable conversion and, to give us more space upstairs, have decided to use steel beams to replace the attic trusses shown on our original drawings. Building Control seem happy with most of the calculations we've submitted but our structural engineer has indicated we need a universal column (203 x 203 x 46 UC) to use as a lintel spanning a 4 metre opening for bifolding doors in an outside 9" solid wall. The problem is that because the beam supports the full width of the wall (as well as the end of a beam supporting the floor above) there's no room to do much about insulating it from either side. How would you suggest overcoming the problem of cold bridging in a case like this? Building Control have understandably asked for this information and I've no idea how to reply. They also want to know how the steel is treated and weather protected. Your advice would be much appreciated. Thankyou

Hi guys/gals, I’m a newbie on here so hope I’ve put this in a relevant place. Next March/April the loft conversion and rear extension are kicking off on my 2 bed end of terrace bungalow. Me and my brother will be doing about 70% of the work, I’m and Electrician and also can do plumbing, getting in a friend to do the roof and rear dormer (as it’s a truss roof). so getting to the point, me and my brother will be removing all of the existing tiles and bringing down all trusses and existing joists. Tell me if this sounds hopeful, but I was looking at getting a 20M x 15M tarpaulin and covering the entire roof, and just putting in a temporary ridge to let the water slope off. This will have eyelet holes and be fixed to external walls. Firstly, would you recommend rear and front scaffolding at eaves height to remove the tiles/roof (if so, any idea on costs)? Or could we just have a movable tower hired? secondly, I need to talk to my chippy friend about this really, but would we need scaffolding for the new timbers being installed? I was thinking that the ceiling joists would be installed from wall plate to wall plate and then that would give us a floor to stand on for installing the rest above? Once all in I can put down the breathable membrane to make it water tight. thankyou in advance for any advice. Here is a picture of the plans just to give you an idea.

Hello I know this topic has already been extensively covered on the forum but there is however a slight variation which i am looking for a solution please.I have spoken to two builders who cannot provide a suitable explantation. Overview Proposed new build extension (drawing below) with 3600mm x 2100mm opening to accommodate bi-fold doors. I have been advised to have a rsj installed above the doors due to weight of roof design. 450mm thick wall construction details as follows (photograph below) Outer 150mm facing in natural stone 100mm block 50mm void 50mm insulation 100mm block The drawing (below) is from an architect.He has not provided a drawing where to position an rsj above the intended bi-fold door. Speaking to a couple of builders they suggest a wide steel plate be welded to a rsj in order to achieve the required width . My questions are - Although feasible - this would not stop thermal bridging? - Where would the bi fold doors sit in relation to the stone / block work - would this also be an issue? Any advise or comments would be appreciated. Thank you very much for any assistance

Hi All, I'm looking for some suggestions for how best to insulate / stop cold bridging across a steel RSJ and vertical steel post that I've had to add to support a glazed gable. I don't have any details at the moment so I want to try and get a plan of action together this before I go and ask BC. I've found to date that they're not always the most helpful ! but that could just be my bad luck! I've got Alu windows going into so was planning on cladding both the steels externally in alu and internally was thinking of plastering the horizontal and alu clad the vertical post. All help welcome! Thanks Alex.

Can anyone point me at the latest wisdom on attaching timber roof plates to steel beams ..? We have two purlins that have the rafters up against them and I was expecting a small birdsmouth on each to slot onto the top plate attached to the RSJ. Previously I've used a spit/Hilti gun to pin them to the top webs however I've been told that's no longer the correct approach ... So I am assuming it's drill and Coach bolt but is that correct and what spacing ..? SE can't help as he just did the steel sizings and doesn't do domestic work anyway.