The purpose and function of a garden or patio wall varies con-siderably. Some people build a wall for the same reason they build a fence -to provide privacy, to screen off an undesirable view, to act as a boundary line, or to simply define areas within the garden. Others build a wall to delineate a planted area or to hold back a piece of sloping ground.
Whatever the purpose of a wall, certain forms and materials serve certain functions better than others. A simple low wall can easily be handled by the amateur; high walls (more than 3 feet), however, are best entrusted to a contractor.
Large bricks create solid wall that blocks street noises. The tree branch comes through the space left open in the bricks.
Staggered bricks create a baffle to give privacy to a window close to the entry walk. Design: Baldwin, Eriksson & Peters.
Concrete blocks screen carport from the patio. Perforated, solid blocks alternate. Design: Ralph Wyatt, Frank E. Martin.
Shadow block wall affords privacy for sunbathers on patio. Ridges on blocks create an interesting pattern of shadows.
Fitted stones are laid in mortar to add extra strength to this retaining wall for upper terrace.
Exposed aggregate finish makes the wall blend well with desert. Top was troweled smooth.
Poured concrete wall can be shaped to any curve or angle; defines a patio area or a flower bed.
Adobe blocks have a natural texture and color that make them blend handsomely with almost any type of garden setting.
Clay tiles are set on a base of concrete blocks, separate parking area from patio..
Poured concrete walls
An advantage to using poured concrete for a garden wall is that you can have almost any shape that you can build a form for. Also, you can have virtually any surface texture from very smooth to rough or embossed.
BUILDING THE FORMS
Building and aligning the forms for a concrete wall takes more time than the actual pouring. Quite possibly, it may take you as many as three or four weekends to construct the form for a special design. Here are some important points to remember:
1. A wall foundation should be twice the wall width to serve as a footing. It should be laid on firm, hard ground or below frost level in winter climates.
2. Forms should be built with lumber that is free of knotholes and straight. Plywood gives a smooth finish and has good strength. The forms should be braced .
3. Curved forms are usually made of thin plywood or 1-inch lumber that is saw-kerfed on the inward side that is to be curved.
4. The inside of the forms should be brushed with an inex-pensive oil so that the concrete will not stick to the walls. 5. Opposite posts should be joined with wire ties to help the form resist the pressure of the concrete. (When the forms are removed, the wire is cut off close to the wall.) Wood spreaders are placed inside the form to hold the sides apart and against the posts, fastening a wire to each spreader so that it can be pulled out as the concrete is being poured.
MIXING AND POURING THE CONCRETE
The recommended formula for mixing concrete for a poured wall is the same as that given for concrete paving . Once the concrete is mixed for a wall, it must be poured in continuous layers 6 to 8 inches deep; each layer must be tamped in place with a 2 by 4 or narrow shovel.
Try to complete the entire pouring in one day. Otherwise, you may have a crack or line where the next day’s pour joins.
CAPPING THE SURFACE
It’s best to cap the top of a concrete wall to prevent rain water from seeping down into it. This is particularly important in areas where winters are severe and where seepage might freeze and crack the concrete. There are three ways to cap a wall: (1) Trowel a fairly stiff mortar (ratio of 1 to 3) on top of the concrete while it is damp and shape it with a curved template. (2) If the wall is to be used as a bench, fasten a redwood plank to the top with 3-inch bolts . The bolts must be set in the concrete while it is still in a plastic state. (3) Apply a masonry sealer after the surface has completely set up.
FORMS ARE LEFT IN PLACE FOR CURING
Once concrete has been poured, it must be kept moist in order for it to set up properly. Use a fine spray over the forms and exposed surface at least twice a day for about a week to 10 days.
HOW TO POUR A CONCRETE WALL
Pour foundation at same time you pour wall if structure is lightweight. Heavier wall usually requires previously poured footing.
Construct form of wood that is smooth, knot free. Brace with 2 by 4’s; place welded wire rods in center to reinforce concrete.
Place spreaders between sides of form to hold them apart. Use wire to loin opposite posts, brace against concrete pressure.
NO FOOTING NECESSARY
ON SOME LOW WALLS Pour concrete using 2 by 4 to tamp in place. Work concrete next to form to force large aggregates away from the surface.
Use wood float to give rough finish to concrete; let water sheen disappear; then use steel trowel to produce smooth finish.
Attach bench seat by using 2 by 6 bolted three inches deep in the concrete. Nail rough or finished 2 by 10 board on top.