The Mortise Tenon Joint System Used in Conventional Timber Frame Arbor, Gazebo or Pergola Kits


“Most all other timber framers use the conventional timber frame way of construction using a chainsaw method to cut it out. This is also how we used to cut it out in the very beginning. We’d take a chainsaw, skill saw, and hack out a “U” shape through the post on both sides. Then we’d slide the other one through, lock it in and then bolt it in.”

“If you are really good you can get a pretty tight seam and it can look great. But after a few months, six months to a year, maybe two years, you start getting these gaps in there. That’s the nature of wood. Wood expands and contracts especially in the outdoors and so thin posts can become brittle and break off and it just looks terrible. That is pretty much how most timber frame kits mortise and tenon systems are designed.”

Chainsaw-vs-dovetail-brighton-9transparency-blankConventional Timber Frame Mortise and Tenon Joints

What Makes A Western Timber Frame Timber Frame Pergola Kit Better

Outstanding weight capacity!

Western Timber Frame™ is known for its massive oversize timber structures. The timbers have an outstanding weight capacity tested to over 5,500 lbs. per dovetail!

We use a massive mortised dovetail joint connection system we call The Dovetail Difference™ throughout our timber construction process creating very strong, rigid joints. On the test pictured here it didn’t give until it hit over 11,000 lbs.!!!


Design and Size Matters

The primary factor in determining the strength and long term durability of the mortise and tenon when loaded with tension is the strength and size of the frame material in connection with the design of cut for the mortise tenon joint system.

At Western Timber Frame™ we cut a dovetail mortised and tenon joint keeping the structural integrity of the post in the center.


“What we have done at Western Timber Frame™ is we invested in the equipment where we actually do a dovetail kind of a mortised notch on the beams and the tails. On the posts this is all the notching we do on the posts so it still keeps the structural integrity of the post in the center. So even if this is a 20 foot beam, after you set the post, it would just slide in, lock in like that and you’ve got this tight tight seam there where you are not going to see the gap. It’s not if, but when the wood expands and contracts outdoors; you are not going to see it because it is behind the dovetail mortised notch.”

Helps to Eliminate Gaps and Exposure

Tight fitting joints in which little movement is allowed between the mortise and tenon can shoulder gravity loads than loose, bolt or peg joints. It gives the timber the ability to expand and contract while remaining tight without seeing gaping gaps.



Another advantage of a Western Timber Frame™ pergola kit is the drop in rafters for a faster, easy install.

Drop In Rafters For Easy Installation

The Drop in Rafters are already marked and slotted there is no need for measuring or trying to figure the proper spacing. The hard work has been done in advance; making installation virtually stress free. However, the primary benefit of the drop in rafters is that it helps to prevent warping and twisting of rafters year after year.

Every Piece Pre Test Fit

Every single piece is tested and fit before shipping which ensures that the installation will be easy and fun. If “kit” brings to your mind crazy times of trying to follow instructions to put together a you on Christmas morning for an anxious child, you can be assured this has already been put together and tested to fit, taking our the stress.

Shipping is Also Free Within the Contiguous United States :)

There are standard sizes of 10’x10′ on up to 16’x16’+ of timber frame pergola kits if you would like to choose from. In reality every kit is truly custom and can be designed in a variety of styles and sizes to fit your needs.

At Western Timber Frame™ we believe the integrity, design and beauty of an architectural structure should be built with future generations to enjoy, too.


Get the Free Ultimate Pergola and Pavilion Guide

Get the Free Ultimate Pergola and Pavilion Guide