roof purlin removal

[Anonymous]

Hello,
I'm having a loft conversion done in a large old stone terraced house. The builders are suggesting removing the large single-span purlin from one side of the roof, to increase the space. They propose to reinforce the remaining 3by2s by doubling them up. It would be handy, but my 'gut' reaction is to leave it alone. Any expert views would be welcome....
Thanks
Simon Brown

 

[Anonymous]

If as you say an " old stone house", the immediate reaction is :- do not remove any sound wood, especially large purlings.

It is not very clear why you need to remove this, and it appears that for such structural roof member to be removed the builders would have some sort of stress calculations made in order to satisfy building control.

Presumably you may intend to istall a window and the purling is in the way.
If this is the case planning dpt. should be informed and proper plans submitted anyway.

If I needed roof space I may sacrifice the odd rafter and make a feature around the purling.
It would be much cheaper, probably make the space more aesthetically pleasing and best of all conserve the roof structure.

 

[Anonymous]

I wouldn't consider removing a purlin without consulting a structural engineer. Your builder may know what he's doing, but can you be totally confident of that? As you're in a terrace, the ramifications could involve more than just your own house (just??!!).
Anyway, how much space would the removal of one purlin create? I can't believe it's much - unless he's also intending to remove one or more collars between the purlins.
I wouldn't let him touch it without an SE's report.