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Timber Frame Construction Details

Offset Mortise and Tenon Joinery

Offset Mortise and Tenon

When you have two beams connecting into one post at the same height, you need to get creative in cutting the joints. The goal here is to make a secure connection without taking too much meat and strength out of the post. In this detail we show you how to accomplish that with an Offset Mortise and Tenon.

Post Top Backcut

Post-Top Detail

This example illustrates a very common assembly in timber framing. That is when a post connects to a tie beam (a horizontal beam, perpendicular to the ridge, that resists the spreading force of the roof onto the walls) or a plate.

Notched Purlin Joined

Notched Purlin

Purlins help to form and strengthen the roof framing in a structure, and they support the roof decking or sheathing. They run horizontally, parallel with the ridge of the timber frame. There are three basic types of purlins: Purlin plate, principal purlin, and common purlin.

Cross Lap Joint Exploded Interior

Cross Lap Joint

Cross lap joints are a great solution when you want to create clean, continuous lines in a timber frame. The edges of the joint are completely flush, making it almost appear that the timbers are magically connected. To create a cross lap joint, you cut halfway through the width of both timbers that you are connecting , and they slide together into an extremely solid joint.

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