I need to create a small raised bed in my garden. Brick would look best, but I don't know how to properly make a brick wall that will support soil. I only need about a 10" high by 6' wide area. Since the ground is sloped, the back will be the existing fence and the brick wall will create the garden bed, without adding more soil next to the fence. Some people have said I need a moisture barrier, others have said gravel is needed for a foundation. Is all that really necessary for such a small wall? Where do I start?

 

Both could be right to some degree, but, if the typical design of a garden box is followed it might end the confusion.

A moisture barrier might be a good idea if the soil is heavy and tends to hold water for long periods of time. The percolation rate is easily delt with using soil amendments, chemical soil conditioners, or digging "shafts" though hard layers, filling the base with rock and the holes with good soil.

A rock base under the footing might be a good idea for the same reason or because the ground is subject to frost heaving.

For something that small and that low a single wythe (thickness) of brick mortared together and laid on a 8" wide x 4" deep concrete footing (where the footing would be 6" below the frost line) should do. For added insurance (frost heaving, or moisture damage) 4" to 6" inches of rock could be placed under the footing.

Start by calculating the depth needed. Wall height + footing + rock (if used). Typically brick will be 4" for the first courses and 3 5/8" for the last course (it lacks a 3/8 mortar joint).

Dig a level trench at that depth, guaging the center of the wall as the center of the trench. Pull a level line between two stakes on one side of the trench and measure from there.

Beat on the ground to compact it. Fill with
rock (if used) and beat on it some more. Place a 1x4 on edge on either side of the trench and stake them (about 2 feet apart) so they are level lengthwise, across, and they are vertical or plumb. Mix ready mix concrete and fill the form. When the water disappears from the surface take a wood float or scrap of 2x4 and float the surface. It should be semi-rough and not butt smooth. After it sets your ready to start laying the brick.

This is where I jump off. Marshalltown (they sell masons tools) has some basic how tos, with graphics, for brick, block, and concrete.

 

ScottD, if the height is only 10", then the task is very simple!! You can go 3 feet or so with a dry (no mortar) wall. First dig out a small trench where the wall is to go. This only has to be a few inches deep. The idea is to use earth to keep the bricks frome shifting. Now lay your bricks - dry, no mortar. If this spot gets a lot of rain (or water from somewhere), then add a couple of 'weep' pipes at the bottom.

By going dry, you eliminate worries from frost. With no mortar, the joints flex.

If you want mortar (strictly for asthetics in this case), then you need a real footer, below the frost line. Failure here means the mortar will crack.

 

I've just built a small wall, it's about 10" high already!! The bricks I used are about 6" in height,the length of this wall is about 5-6 feet!! the foundation is about 8" deep made with ready mixed concrete,my problem is I would like to go another brick high, would I get away with it???? Neilll