Building control query regarding roof purlin

[Hampshxre]

Hi,


I am seeking guidance regarding some work I previously carried out on my property without Building Control approval, which I am now looking to regularise. Please see the attached photographs for reference.





When I purchased the house, it was formerly a council property and the roof covering had been replaced approximately 2–3 years prior. During that work, the chimney stack had been reduced to loft level and left in place, as it was providing support to a timber purlin on one side of the roof. The purlin had been cut on either side of the chimney stack.





Subsequently, I installed an additional timber purlin of the same size and length alongside the existing one, securely coach-bolting the two together. Once this was in place, I removed the remaining chimney stack entirely. The chimney was not providing support to any other structural elements aside from the purlin/roof arrangement described above.





I would be grateful if you could advise whether this work would be considered acceptable by Building Control, and what would be required for it to be approved retrospectively.





Thank you for your time and assistance.

 

[Ollyfp]

We need photos really. Is the purlin supported by uprights that have been 'bird-mouthed'?

 

[Hampshxre]

We need photos really. Is the purlin supported by uprights that have been 'bird-mouthed'?

Just uploaded them mate. Let me know if you need any more

 

[freddiemercurystwin]

Is this a loft conversion?

 

[noseall]

I would be grateful if you could advise whether this work would be considered acceptable by Building Control, and what would be required for it to be approved retrospectively.

BC want a paper trail. You need a suitably qualified report from an SE or some such to underwrite what you have done structurally with the roof - or to advise/instruct what needs to be done to remedy.

I doubt they will settle for anything less even if you were install a 500mm deep steel beam up there.

 

[stevie888]

You have doubled the span on that purlin by removing the central support. To get the same resistance to bending you need a beam that is 16 times stiffer so unless you are providing vertical support then it's a resounding no. If you have supported the purlin from below then you didn't need to put the full length piece in.

 

[Ollyfp]

I've completed a similar project. We had to put 4 flitch beams in to span the various supporting walls downstairs. That's the reason we use an experienced architect. All the finer details should be included on the drawings, with the exception of the engineer's final calculations for beam sizes etc. A member of my family used a young architect with no real understanding of materials, drain runs, etc. Big mistake.

 

[Ollyfp]

Did you take out the chimney breast in the room below? If the new timbers are supported by the remaining brickwork, you should be golden. I've only completed 6 renovations, so other contributors are far more knowledgeable regarding these matters.

 

[cdbe]

Have you left a 50mm ventilation gap above that rafter insulation?