Large glazed extension
On the hottest days of the 2015 summer, we raised this oak framed extension over in Langham, West Suffolk. The contemporary design has an emphasis on clean straight lines and had already been drawn up before we were able to get too creative!
The following shows the extent of the framing. A storey-and-a-half core (bedroom, kitchen/sitting) and two wings providing a dining room and utility space. With a limiting height of the existing ridge, the first floor is effectively half within the roof space. The extended wall plates to the front are to provide a huge 1m deep verge overhang.
The extension envelops the rear half of the house, which is not really clear on the above image. If you are architecturally minded, the following layout might help make more sense of it.
On the first floor, an open truss design was needed to make use of the available space. Normally this can be achieved by interrupting the tie beams with vertical posts, as has been done on the gable ends. This would have broken the available floor space up and was not desired. Therefore, the three central trusses had to be stronger to help resist the tension forces. This was achieved by using through tenons, which help prevent the trusses from spreading at the base.
Raising the frame.
Due to access, each of the timbers had to be brought in by hand and some sections pre-assembled ready for raising. The sole plate was set out and sections were brought in with a crane into their appropriate positions.
The first lift…
This ‘H’ frame was carefully positioned, then girders connected to open mortices (in face showing next to main cross-rail). Then the second ‘H’ frame is connected and the process repeated.
When all the frames have been put in place, the wall plates can be dropped into position and the structure is effectively secured.
Then just a simple case of dropping in each of the trusses and the job is done!
From the inside, this gable truss has an opening to take some large double doors to make the most of the views.
From this angle, you can get a feel for the space, note that all of the external faces are to be direct glazed.
And one last unusual detail is traditionally chiseled numbering to the inside faces.