© 2014 by Raymond Alexander Kukkee
Carpentry Retro: Build with Rafter and Ridgeboard!
Do you know what rafter&ridgeboard construction is? Most trained carpenters are familiar with rafter and ridgeboard construction because most homes in the past were built with this essential, reliable, strong construction technique. This timeless, and relatively simple construction method has fallen out of favour because of the convenience and availability of trusses.
The Modern Truss: Alternative to Rafter and Ridgeboard Stick Framing
A discussion of rafter and ridgeboard stick frame construction would not be complete without an explanation why the use of trusses has become more popular. The modern home builder today is more likely to use pre-manufactured trusses which incorporate ceiling joists, rafters and engineered web designs into single units which are incredibly strong.
Individual rafters, ceiling joists and other web components are all computer-designed and assembled with steel gussets into a ‘truss’ structure. The gussets are gang-nailed together, or today, more likely press-assembled with specially-designed steel gusset plates at the time of manufacture. An engineered truss offers rapid installation of the exterior roof framing and interior ceiling framing of a home simultaneously. With trusses, wide spans can be achieved without central load-bearing walls, posts or beams. Much time can be saved in construction by using trusses on large projects.
Trusses for a small building such as a shed , play house, or doghouse are not necessary. Even for a modest full-sized home, rafter and ridgeboard construction is fast and efficient and can be achieved by competent carpenters and moderately-skilled DIYers. Your closest long- established neighbourhood in any city has many homes that demonstrate the method is reliable and strong enough to last for centuries.
Building with Rafters and Ridgeboard
Rafters are established in opposing matched pairs to form the roof, with each rafter leaning against, and fastened to a pre-installed ridgeboard at a calculated height with another rafter immediately opposite. The length of the rafter is calculated using the simple Pythagorean geometry of a right-angled triangle.
The chalet style shed in our photo has a 12:12 pitch slope (45°) and a wide overhang. The pitch of the roof must be decided prior to making any rafter cuts.
The rafter, after calculating carefully for length, is cut short at the peak to allow for half of the thickness of the chosen ridgeboard which may be a 1×6″ or 2″x6 dimensioned lumber. The length of the rafter is calculated from the actual peak to the vertical cut for the bird’s mouth notch which is made in the underside of the rafter at the top of the supporting wall.
An allowance for the overhang of the rafter is added to the rafter length calculation. The top end of the rafter is cut vertically to accept the fascia board. The fascia boards and ridge boards are both measured long enough to extend past the end walls, again to allow for overhang as desired and carry the ends of the ‘fly rafters’ on either end of the building . An overhanging ‘ladder’ assembly may be built to resting on the end wall, or simple ‘lookouts’ may be used to fasten the fly rafter .
*Hint: Cut one matching pair of rafters (opposing) and try them. If they fit perfectly, use them as patterns for the remaining rafters.
In typical stick-framing, (don’t you just love that old carpenter term?) ‘horizontal ‘collar ties’ would be nailed onto the opposing rafters close to the apex of the roof for added load-carrying strength. Additional collar ties to and from matching opposing rafters may also be added at the mid-point of the rafter. Doing so substantially improves the strength by creating what is in fact a simple truss. A diagonal support brace from the wall plate to the peak of the underside of the roof may be installed and fastened to each of the rafters to establish spacing and dimensional stability prior to roof sheeting. Following the installation of the rafters, ceiling joists may also be installed if desired.
See the photos! The beautiful symmetry of rafters carefully installed in stick-framing has a certain elegance…
Here’s an over-simplified diagram.
Simple, isn’t it? Now you can build that dog house or play house with a storage space. Or a chicken-coop for the egg-laying chooks. Or a whimsical peaked roof for a wishing-well. Or a protective porch over that back door. The application is endless. After a small project is complete, try a larger garden shed too.
Apply the rafter and ridgeboard construction technique to your next building project and you’ll have discovered the joy of genuine stick-framing . Happy Building!
Is that Incoming I hear?
*Photo credits and diagram © 2013 rakukkee All rights reserved.