Tuesday, May 13, 2008

The Difference Between Post & Beam and Timber Framing (Part 2)

TIMBER FRAMING is a type of post and beam construction which uses traditional mortise and tenon joinery and wooden pegs to join timbers together instead of metal plates, screws, and brackets. Instead of posts and beams butting to each other, timber frames are designed with timbers that typically span from floor to roof.

There are two general types of timber frame systems, each having several variations: Common Purlin systems consisting of King Post, Queens Post, and Hammer Beam frames (photo above right) for example, and Common Rafter systems such as Collar Tie (photo below left), Principal Purlin, and Ridge Beam frames. There are many reasons to choose one frame type over the other (addressed in a future blog), and costs vary as well (Hammer Beam frames are generally one of the more expensive timber framing systems, while Principal Purlin and Common Rafter are usually the least expensive).

Timber frame bent systems are typically assembled on the first floor deck, then raised as whole units into place by a crane (see photos bottom), connected with the joinery, and secured with wooden pegs. Because of the structural integrity of these bents, timber framing tends to allow for a more open, flexible floor plan than post and beam construction.

Common Rafter systems are raised either as ‘walls’ or similar to post and beam homes, one timber at a time. Timbers are erected in succession; one end post erected first, then a connecting beam at the second floor level is secured to the post, then another end timber is joined to the beam. Timber ends are fastened with some form of mortise & tenon joinery. Joints are typically fastened with pegs, which can be cut flush to the joinery or left protruding for decoration.

Whether you prefer to build a post and beam or timber frame home, getting the advice of a design professional is important. Seeking the services of an architect who specializes in timber frame or post and beam construction can save you money – and frustration – in the long run. If a green home is your desire, find a LEED (Leadership in Energy and Environmental Design) accredited architect you want to work with. A LEED accredited architect will be able to assist you in all phases of sustainable design, evaluate your individual design needs and priorities, appraise your site and its environment, present you with exterior and interior green material choices, as well as water efficiency, heating, cooling, and electrical systems and guide you through other design and material considerations in building your new home. For more information, click to read Three Reasons to Use an Architect by the American Institute of Architects. Also see our past blog Why Hire An Architect?

Jackie Lampiasi, Marketing Director
Bonin Architects & Associates, PLLC

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