Box Ends

What are box ends?

Box ends are components of a gable end roof and are assembled at the soffit and fascia line of the eaves. A boxed end is a form of aesthetic boxing that ties the barge board and potential soffit into the regular level fascia and potential soffit. If the level fascia on the ends of the rafters featured no soffit and no overhang, the barge board would come down to meet the end of the fascia run with a plumb cut. This is rather uncommon in modern construction, as the common inclusion of a soffit overhang serves both a practical and aesthetic purpose.  

With the overhang of the soffit present, the barge board will still come down to meet the end of the fascia, though we are now left with an unsightly exposed end to the eaves. To overcome this issue, and tie the two components together correctly, a box end is formed. Here we shall look at how box ends are formed.  

How are box ends formed?

As we look at the corner of the roof where the box end will be formed, we can see that the level plastic soffit and fascia are already installed. The supporting timbers for the box end need to be installed so that the barge timber or plastic comes into them. That being said, the barge plastic can be installed and left long and buzzed off with a multitool when it comes to forming the box end. Alternatively, the boxing supports can be formed first with the plastic capping being installed after the fact. Aesthetically, the primary component of the box end is an additional small section of fascia board that is shaped to meet the profile of the roof. This piece of plastic, or timber, turns around the corner at the end of the fascia run for a short distance, before returning again back into the building. This provides a finished end to the level fascia, so that the barge board can come down neatly into it. With these finished components in mind, we can turn our attention to installing the supporting timbers that will form the shape of the box end. 

The first step is to install a solid timber between the outside barge rafter, and the next timber in from the end of the roof. The underside of these timbers should be level with the underside of the timber fascia backer board, so that the soffit is adequately supported on this outside edge. The timber should be wide enough so that adequate fixings can be installed through the sides of the rafter to hold it in place. It should be pushed back tight against the external masonry, so that the small fascia return will just meet the front of the masonry. If a soffit ladder is present, then it can either be cut off to suit this installed blocking or continued into the barge rafter to serve the same purpose.  

The other piece of supporting timber is the missing triangle on the underside of the barge rafter, on the end of the installed blocking. This triangle is screwed to the underside of the rafter and the solid blocking and provides stability to the fascia as it returns around the corner. The angles of the triangle are just the standard angles associated with the pitch of the roof.  

With all the timber supports installed, the plastic is ready to be installed. In this setup, the level soffit and fascia extend all the way to the outside of the barge rafter. A small section of fascia is installed on the returning support timber from the outside of the barge rafter to meet the external masonry. An extra deep section of fascia must be cut to the profile of the roof between the two returning sections of fascia. It's typical for the eaves cloak to change pitch slightly at this point of the roof to accommodate the kick of the tiles, and so this must be accounted for when cutting the profile of the end cap fascia. Two plastic corners can then be cut and installed on these two external corners. Both the barge soffit and fascia can then come down to meet this finished box.