Friday, June 01, 2018

Trellis Project


The Situation

When a former owner of my house decided to add an extension at the back, he decided to minimize the cost by using a corrugated plastic material for the side wall of the unfinished space below the new master bedroom.  Over the years, this material became grimy-looking, which became more evident when new siding was put on the house.

The Plan

I didn't want to paint this wall, because the material is translucent, and allows daylight to illuminate the storage and shop area inside.  Instead, I decided to hide the ugly wall and the air-conditioner compressor behind a trellis.  Garbage cans could also be hidden behind the left side of the trellis. This was also an opportunity to make a raised bed for an herb garden.  The trellis would rest on the back edge of the raised bed.  Clematis could also be planted in the raised bed and allowed to climb on the trellis.  Hinged 'gates' at either end of the trellis would allow access to the garbage cans and to the AC compressor.  (The white space at the bottom right of the diagram represents the neighbor's fence.)




Notice that the gates at either end of the trellis are co-linear with the angled ends of the raised bed, both at 45-degree angles.  (The angle of the lawn edge is parallel to this angle on the right side.)  The trellis has five panels: two gates, two wide panels, and one narrow center panel.

Phase One

The first phase was to re-locate the step-stones further away from the house and to re-shape the lawn edge to make two 45-degree turns instead of one 90-degree turn.  The white stones were washed, and new weed-stop fabric was installed under the white stones and step-stones.

Phase Two

The second phase was to build the raised bed for the herb garden, filling the bed (including two feet deep below ground level) with good loam-rich soil mixed with plenty of sand for good drainage.

Phase Three

The last phase was to build the trellis, fastened to the back edge of the raised bed, and kept from tipping over by braces fastened to the bottom of the siding..  Notice that the holes in the trellis are larger at the top and sides. Next, we will describe this phase in more detail.

Pre-assembly

The frames of the various panels were pre-assembled from 2-by-3-inch lumber and painted before the final assembly. There is no pre-assembled frame for the narrow center panel because it is just the space between the two wide panels.  (It only needs top and bottom frame pieces.)

After painting, the vinyl channel strips were screwed onto the wood frames, holding the vinyl trellis panels in place.  The channels are supposed to allow for the expansion and contraction of the vinyl trellis panels due to temperature changes.  But adjusting the channel positions is tricky: Where is the current temperature relative to the minimum and maximum temperatures?

Tip-over Bracing

The trellis is kept from tipping over by braces (made of 3/4-by-2-inch wood) fastened to the top of the trellis and the bottom of the siding on the house, as shown here.

The Center Panel

The center panel only needs top, middle, and bottom horizontal frame pieces, because it shares the vertical pieces of the wide panels on its left and right. These horizontal pieces are fastened on the back side by metal straps with built-in 'nails'.


The Gate Hinges

Each gate is allowed to turn inward by 45 degrees by rip-cutting a 2-by-3-inch piece of lumber on a diagonal, making two 22.5-degree wedges, and adding a wedge to the hinge side of each frame.  This photo also shows the ends of two channel pieces, and the strap fastening one end of a brace.

Each strap hinge is positioned to allow the gate to swing open all the way (180+45 degrees). The straps were too long, so each strap was cut shorter and a new beveled hole added.

Square-angle Bracing

To keep each rectangular panel 'square', that is, with square corners, heavy wires were installed diagonally, anchored by eye-screws, to pull opposite corners toward each other.


Since each gate is supported only on the hinge side, only one diagonal wire was installed, to keep the outer edge from sagging.

The tension of the bracing wires will be more easily adjusted by using a tension adjuster like that shown here.  Left- and right-handed threads enable turning of the joining part to change the tension without turning either end of the device.

Gate Latches

Each gate is held closed by a latch-bar, seen here at the top of the gate.  Lifting the end of the latch bar releases the gate. The latch bars are made of the same material as the bracing bars.

A piece of wedge material is added to the top of each gate, the wide side of the wedge toward the outside.

The latch-bar is notched at the bottom to catch the wedge on the top of the gate, and an eye-screw is positioned on the bottom of the latch-bar to prevent the gate from swinging inward too far.  The bottom of the latch bar is beveled at the end to help ease the latch bar over the wedge on the top of the gate.

Each latch bar crosses a brace bar, and they are fastened at the crossing point by a screw.  The flexibility of the latch bar is used to apply pressure at the notch.  A natural bend in one of the latch bars was used to choose and adjust the position of the latch bar.
 

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