BS 5268-7.4:1989 recommends a calculation basis for the permissible clear span of ceiling binders used in traditional pitched roof construction, i.e. not including trussed rafter roofs. The method of calculation is for single span ceiling binders formed from solid timber and supported at each end by external or internal walls. The roof space is assumed to be accessible, thus both uniform loads and a single concentrated load are considered.
BS 5268-7.4:1989 is applicable to the species and grades of timber given in BS 5268-2.