A scissor truss is one of many designs for a truss. A truss is an engineering term used in architectural and structural designs. It is a triangular shape which varies depending on the end user requirements. To make a truss you will follow some basic construction steps. The most common use for a truss is for roof construction. Most truss construction is made of strong wood with metal joint plates that hold the wood pieces together. All the materials for a roof are anchored by the truss. The truss will bear the weight of the entire roof. A scissor truss design consists of a triangle compressed to look like the two shear blades of a scissor. A scissor truss allows for a high open ceiling.
Step 1 - Design
Work with a qualified architect to design your truss. The aesthetic value an architect brings to your design will be relevant when the room is finished. Next, work with a structural engineer who will give you exact measurements for the specifications necessary to have a safe truss. Make sure you check with your local building department before beginning any construction project.
Step 2 - Prepare the Work Area
A truss should be built with the wood laying on a flat surface, outdoors. You will need an area large enough to accommodate the height and width of your truss when it is completed. The best way to install a truss is to lift it into position from its construction location. Set up your saw in the area you plan to cut the lumber. Arrange a space where you will assemble the truss. You will cut all the lumber at one time, so include an area where you can separate the pieces according to their size and placement in the truss.
Step 3 - Cut the Lumber for the First Truss
With the correct dimensions from your structural engineer you should be able to cut the lumber without any problems. It is a wise move to only cut enough wood to construct one truss at this point. You will then build one truss prior to cutting all the lumber. If any adjustments are necessary, this is the time to find that out.
Step 4 - Build the First Truss
With the pieces lying down, form the scissor truss as the engineering design dictates. Bring the pieces together, place a nail plate on the joints and gently tack them all together. Measure the completed truss and compare those measurements to the specs you received with the design. If necessary, make any adjustments and note those changes.
Step 5 - Cut the Lumber
Using any adjustments you may have made from the first truss construction, cut all the lumber for all the trusses. Construct one truss at a time, making sure that you center the nail plates to the joints and each board when attaching them.