Minimum joist size for Loft

[Andy_B]

I want to make use of my loft space for storage and need to fit new joists above the existing ones with hangers screwed to the wall.

The height to the apex is only 82" so joist height needs to be kept to a minimum to provide maximum head room. The span is 12' and there are no internal supporting walls upstairs.

My question is what is the smallest size (height wise) joist I can get away with and what would be the best hangers to use.

 

[amtodd]

I've posted an answer to this question before. If you go to this post //www.diynot.com/forums/viewtopic.php?p=1556&highlight=#1556 you can find the hyper link for the governments' building regulations which are available as PDFs.

You will need Table A1. Most timber will be grade 3 (stamped c-16) unless stamped c-24 when it will be grade 4 and much more expensive. Use the middle weight loadings because your local building regs inspector will be using those when he checks.