Guild Member Bob Moulton, of Moulton Custom Garage Door Company in Duxbury, VT, is a native Vermonter who studies traditional North Country buildings in order to develop credible, accurate period detail for high end garage doors. Recently, he has furnished doors for a residential barn conversion in which the first floor was dedicated to a three bay garage with living quarters directly above. He removed weathered board and batten siding from the back of the building to build a garage door that disappeared into the existing historic fabric. A recent Adirondack style door for an historic “camp” was covered with peeled logs. As a design feature, taller windows increase the illusion of period doors since they draw attention away from the sectional, horizontal format of the overhead door. For technical reasons, the top section of the door can be significantly taller than the others. Just, as it happens, where you might need to place a window.
To control the cost of heating these large spaces, it is necessary to seal these oversized openings and to insulate them well. A diligent and experienced technician can create a door seal as tight as any other door opening in the building. The door is fitted and installed first and then the mechanicals are located back from there. The R values are determined by the base material of the horizontal door slabs, plus the cumulative value of the covering material. The base slab material is either a foam filled hollow core wood slab or one built out of a tube of 20 gauge sheet steel with an insulating value of about R16. The wood core slabs have much lower R values but offer a higher level of design flexibility since they can be fabricated to almost any width.
Door size has increased along with that of the garage itself. The old standard door size of 8 by 7 feet is now no longer stocked. Bob Moulton finds himself working mostly with sizes of 10, 12 and 14 feet in width and 8 feet tall. He recently built an 18 foot by 11 and a half foot door for a garage with a 26 by 52 foot footprint. The steel door weighed 1,800 pounds and bore a cover depicting two pairs of double swinging doors, with hardware, separated by a raised mullion or pilaster. As base layers, finish, trim and false hardware are added to the cover, R values will increase significantly above that of just the slab but so will overall thickness and weight. A covered steel slab can finish out three inches thick. The capacity of all the mechanical systems must be increased to carry these heavier loads. Whatever the weight, if it is carefully counterbalanced, it will be easily opened by hand in an emergency, should the vehicle be needed during a power outage.
By John M. Corbett