The new barn room sits alongside the house with ease, mirroring the pitch of the two existing and new dormers. Although the finished structure looks contemporary and minimalist from the outside, the design and carpentry work involved would prove to be one of the most challenging domestic structures Carpenter Oak have ever completed.
For frame designer Paul Slemmings, it was a first – when the principal rafters aren’t at right angles to the walls and ridge, some outrageously complicated geometry was required to align the ‘X’ shaped tie rods in plan at different heights with no coupling ring – all set apart by a sensible distance to ensure that the tie rods would not touch.
It was further complicated by being a composite structure – we had to design and cut around existing steel on site – one of the frames has a post omitted to not impede access into the room, so had to have a mid plate with a slot cut into it, that would fit over onto a piece of steel angle that would later be concealed by the builders.
The clients wanted to see through the glass and posts from the inside the existing house but with minimal steel on show. The essential six pieces of steelwork that provided the internal rigging were as slender as possible, with 12mm tie rods as thin as we would go on a job of this nature.
What made this design especially complicated was the way the principle rafters met through the pendant in the middle. Because the trusses were not set at 45 degrees in plan, they have to have a dog-legs in every truss, so the steelwork in plan wasn’t following the line of the principle rafters. Using a steel ‘rolling-pin’ through the principle rafters and spherical washers that would rotate when the nuts were tightened made sure the soft stainless steel wouldn’t cold weld and get damaged.
‘Fundamentally, this was a real head scratcher – crazy angles left right and centre and probably the most geometrically challenging job we’ve ever done – up there with Radley College in terms of calculating angles of cuts for purlins – it was right out there.’ Paul Slemmings, Frame Designer
Solar thermal panels are located at high level on the new roof of the main building, and the south facing garage roof houses a large photovoltaic array, connected to a Tesla battery pack. The ventilation is supplemented by an MVHR system to recover heat and recirculate filtered air for improved comfort with minimal hea tloss. In addition, the house is provided with a new charging point for electric cars and smart technology throughout the building to allow remote control of all installations.
‘We are thrilled with our Barn, the room has turned out to be a real focal point for the house and the place where we host large family gatherings. We receive a lot of positive comments from visitors and happily recommend Carpenter Oak when asked ‘who made such a wonderful structure?’’ Paul Callingham – client