Purlin removal/replacement

24 Jul 2022
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United Kingdom
Hi all,

My bathroom sits under a pitched roof and is uninsulated throughout. I am planning to internally insulated the walls and ceiling. The purlins from my roof sit within the ceiling in my bathroom and reduce the head height in places (see photos). Is it possible to remove this purlins and replace with a steel purlin Perhaps one that is fairly thin as i wanted to board the ceiling with insulated plasterboard so it would be ideal if the purlin is thin enough to be boarded over.




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Yes. Probably easiest to install the new purlin beside the existing one with it still in-situ and remove it afterwards so you won’t need to prop the roof while you do it
Cheers, got any insualtion advice? I need the thinnest most effective possible for the ceiling to.keep the height. I'm going to lower the bath by 10-15mm. I was looking at some bubble foilstuff from screw fix

Or this roll insulation from spacetherm. Would need extra vapour batiier with this (but more expensive though)

Personally I'd remove the ceiling, fit whatever celotex I could between the rafters while maintaining a suitable (25-50mm) air gap above, then underline with continuous celotex - I would use 100mm to bring it flush with the bottom of the beam.

I doubt you'd gain much swapping the purlin for steel and it would be a massive cold bridge if not heavily insulated, and theoretically would require structural calculations and building regs approval.

Most people don't recommend those quilt insulations.
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Thanks cdbe. The problem with all that insulation is that it will make the height of the ceiling very low. Ideally I would like it at the same height or only loos upto 20mm. The other problem is that rafters are only 50mm (it's a small roof) so I would be able to place any insulation inbetween them.
I,m guessing it was never meant to be a bathroom
Something looks odd but I can't put my finger on it!

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