Good afternoon,

We have started loft conversion today. Sadly after builders uncovered the roof they discovered that unlike structural engineer's assumption (they were buried under insulation), the existing joists are not resting on the wall but are attached to rafters which then take the load to the wall which is much lower. d

I have made peace with the fact that new floor joists will have to be similarly attached to new rafters and then supported off the wall but the problem is with a new UB steel beam that will have to be supported off this wall and is considerably higher than existing joists which will cause UB sticking out of the roof. Steel beam cannot be moved due to chimney and new staircase making this the only possible configuration. My builder is saying that we will still have to support beam from the wall and he will build some sort of box covering the extent of the beam sticking out. It will obviously look hideous.

Is there something that can be done to avoid the box? I have measured and sketched the current state. enter image description here

Any advice appreciated.

Thank you.


  • 1
    It is not uncommon for beams to have an angle cut on the end, but that obviously requires that the beam can be adequately strong with such a cut, and if you have an engineer on the job I would think they would have considered that, and evidently rejected it. Change "ugly box" to "tiny dormer window" and see if that alters your perception of hideous-ness. The "window" would not be functional as a window, just a "nicer" common roof addition than a "box." – Ecnerwal May 8 at 14:59
  • Yes, it is not possible to make a cut because if we would make it to be flush with rafter ( to hide under under the roof) the beam would not come far enough to be supported off the wall. It can be seen from sketch. – Ben Bord May 8 at 15:29
  • 1
    This is sending you "back to the drawing board" to rethink your entire design. It sounds like you are pressing forward with your plans anyway, even though you now know your plans are incompatible with your building. People often uncover past building modifications that are completely nuts, like "what were the renovators thinking!??" Now you know what they were thinking. – Harper May 8 at 15:48
  • Hideous ?. Clearly if want to avoid being the object of scorn and ridicule in the neighborhood you will need to take the whole roof off and start over so you will not be associated with such a "hideous" structural detail. I guess the question is; how much money are you willing pay to put form over function? – Alaska Man May 8 at 16:28
  • I am already taking down the whole roof. The problem is that it is a terraced house and I am not allowed to build passed the line of current roof. So rising a roof is out of question. I've been told that typically it is possible to solve with cranked steel beam, but there doesn't seem to be enough space for it. – Ben Bord May 8 at 17:37

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