I'm getting ready to do some remodeling that may affect some purlin supports that are in the attic. Basically, I'm wondering if they were just put there to temporarily hold the rafters in place during construction of the roof structure (house was build in the late 40's). They are somewhat randomly spaced as they are not on every rafter (I'd say about every 3rd or 4th rafter). Also, while the main house structure is very well built, these appear to be made from almost scrap wood and poorly nailed. The rafters are 2 x 4's about 16-18' long from the eave/fascia board to the top center of the roof, spaced at 24". Most of the purlins are made from 2 x 4's but a few are 2 x 3's.

Thanks for any help and again, just wondering if they are truly structural or were just used for temporary support.

Thanks,
BB

 

They are likely there to take the spring out of the roof. Your rafters are likely undersized / overspanned.