In this post, we’ll explore the two most common ways of assembling shutters – and why paying a little extra to have yours built with mortise & tenon connections is the best option!

Wimpy, Wimpy, Wimpy -- Most manufacturers rely on small wood dowels to hold their shutters together.

Most manufacturers assemble their shutters using wood dowels. A dowel is a small, cylindrical piece of wood that forms a bridge between two pieces of wood. If you’ve ever assembled an inexpensive bookcase or filing cabinet, you’ve probably experienced wood dowels.

For a manufacturer, wood dowels are an inexpensive way to quickly construct a mass-produced product like a shutter.  Shop managers are able to pump out more product with less personell, especially if they employ machinery to help automate the process.  Less personnel and faster production lowers overhead costs for the company, and in return, allows them to sell their shutters for less. To further cut costs, manufacturers are moving more and more toward not adding screws for additional strength.  Without the extra screws, the entire weight of the shutter rests on wood dowels.

For wood dowels to effectively hold a plantation shutter together, they must be glued.  To ensure the best connection, it’s best to apply the glue to dowel itself, and then insert it into the hole.  Excess glue is forced out as the dowel is pushed deeper.  Unfortunately, that is a very slow process to do.  Many companies have resorted to shooting glue into each hole, then doweling and clamping the components together.  The result is that excess glue is not forced out; it is merely compressed. Unless the components are clamped together for at least five minutes (which would dramatically slow production down and thus is often not done), the glue will not fully set. Without the extra screws to hold the shutter together, hydraulic pressure from the glue will eventually begin to push the dowel back out. Depending on how much excess glue exists, the shutter will begin to sag and then separate anywhere from six to eighteen months later.

Since most people leave their shutter panels closed, they may not see this in the look of the shutter itself.  But they will notice more and more light breaking through the top of the panel as the shutter begins to sag.  Since light control is a huge reason why people choose plantation shutters, a poorly constructed sagging unit that permits excess light to enter robs homeowners of the value they thought they paid for!

Enter MORTISE & TENON: the white knight of high quality shutter construction.

Heft, Hefty, Hefty -- Sewell's mortise & tenon construction techniques ensure long lasting durability.

A mortise is a hole or groove cut into a segment of wood.  A tenon is an outcropping from adjoining piece of wood that is inserted into the mortise.  Whereas a dowel is a separate tiny connector bridging two pieces of wood together, mortise and tenon actually connects the two segments in a very sturdy fashion.

With Mortise & Tenon construction comes the following benefits:

• Increased surface area for glue application.  More wood surface glued, the stronger the connection.  Because glue is applied to the tenon and then inserted into the mortise, excess glue is pressed out and a tight bond is secured.  No excess glue, no hydraulic pressure, no separation of the shutter!
• A seemingly solid piece of wood is produced from two segments fitting snugly together.
• Two similar wood segments glued together will expand and contract at a similar rate (from temperature changes or humidity), so the connection will not break loose.  Can the same be said for adding a cheap dowel of a different wood species?  What happens if the wood in the shutter expands at a different rate than the wood in the dowel?  The connection becomes even weaker, that’s what!
• Although not absolutely necessary, a quality shutter manufacturer will still screw the the mortised/tenoned segments together for added durability.
• The ultimate benefit – plantation shutters will remain straight and sturdy, never sagging, for twenty, thirty years, and beyond!

At the end of the day, Americans buy homes to invest in their future.  Invest in your window treatments!  The next time you shop for shutters, remember to ask your contractor to build using mortise and tenon!

Gluing Mortise & Tenon

Screwing Mortise & Tenon for Added Strength