I am in the process of cutting a vaulted oak framed gable which cuts in at 90 degrees to the main roof of a new extension to my property. The two valleys are to be constructed with oak beams which run from the wallplate (building plate) of a conventional block cavity wall (U.K. build) up to a steel “I” beam which is used as a side purlin in the main roof .
The two oak valley beams have been sized by an engineer at 10” x 5” timbers. Note. The ridge purlin of the vaulted gable will also meet the two valley purlins at the steel beam. (I imagine I will have to fabricate some sort of hanger at this point, however that is another problem). Back to the vaulted gable, there are three purlins on this gable all sized at 7” x 5” – one at the ridge, mentioned before and one either side of the gable, halfway between ridge and wallplate. One end of the side purlins is built into the block gable end and the other end is to be framed halfway up the valley beam. My question is what would be a suitable joint at the point where the side purlin meets the valley beam (the side purlins are to be at 90 degrees to the rafters of the vaulted gable and rafters will be peg jointed) I hope I have painted a clear enough picture of the roof !
Any ideas would be greatly appreciated.
