Assume you mean ceiling joists. If they run parallel with the wall then the wall is unlikely to be load bearing. Any loading on the ceiling joists will to some extent depend on the roof design but in most cases they do not carry a great load, there job is to restrain the outward movement of the roof rafters. Most of the load will be from plasterboard, Insulation, water tanks, loft boarding and all the junk that most people store in the loft!! If you decide it is load bearing you may be able to get useful information from the 'Catnic' lintels website (product selection) Regardless of wall type "If you wish to build a new internal wall, remove an internal wall, or form an opening in an internal wall, building regulations will normally apply".
Many thanks for the reply. I have looked again more closely, and the wall is not load bearing, but is half way along the joints, so would support any junk that gets put in the loft. Also looking to the future, the roof structure would be ideal for a loft conversion at some point in the future. Therefore assuming I need an RSJ, what would the merits be if I went to a builder, or a structural engineer?
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