Minimum thickness of beams for attic conversion

Horlock

Looking to do an attic conversion on a bunglow.

Current beams are only 4inches thick - I'm guessing I need thicker.

What are the legal restrictions?

I thought it was 6 inch, but a friend thinks it may be 8 inch.

Or does it vary - dependant on width they are spanning etc

ormus

there are lots of variables to consider before anyone states you need 4 or 6 or 8 inch joists.
you might even need a steel RSJ. some buildings require nothing extra.
a structural engineer will tell you.

jkpd

as ormus seek advice,6" will span about 3m 8" about 4m mostly you have to insert steel or if internal walls are not loadbearing you can underpin,if internal walls are loadbearing you are laughing.

Horlock

Thank you, sounds good, the widest I need to span is about 2.8m so I may well be in luck!

Thanks again. will chat with planners.