looking for how to's/tips on building castlewall block retaining wall....

[blacksunshine]

looking for how to's/tips on building castlewall block retaining wall....

have a couple of trees in the front yard and want to use those castlewall blocks to make short retaining wall island thing around them. it is not a flat area and wondering what the tricks were to start...ie where and how...

is it start off at the low end and have a sledge around to pack the dirt down where needed to get the bedding down as needed to keep the plane?

[100%TtId]

How much slope do you have and how big is the tree? Post a pic if you can.

Consider how big the tree is compared to its lifecycle. Is it fully grown? If not, consider a larger diameter wall to accomodate growth and root spread.

A lot depends on the size of the blocks and how tall of wall you need. And also if you're wanting to retain dirt out (like in a tree well) or retain dirt in (like an island).

3-4 courses is usually as high as you want to go with castlewall blocks even if you have a severe slope, 5 at the most. Beyond 5, castlewall is not a good choice. Do you want a complete circle or just an arc of a circle?

Normally you would dig a shallow trench 4-6 inches deep around the tree where you want the ring to be and fill it with pea gravel (tamp it down) to use as a leveling base. But in your case with a slope, you want to be careful not to disturb the soil too much around the roots or compact the soil where the roots are close to the surface.

If you backfill the wall with soil remember that you're adding soil on top of roots, so don't add more than 2-3 inches and use good planting soil to fill, not heavy clay soil or you will smother the roots and kill the tree. If you have a severe slope that you backfill more than a few inches, insert some perforated pvc pipe into the ground vertically before you fill to allow air to penetrate into the root zone.

These types of blocks have to be installed perfectly level or else you will have many problems and it will leave gaps and look terrible. Get a construction bubble level at least 24 inches long and use it to plumb the trench, the blocks both fore and aft as you place each block, and each run of 3-4 blocks. It gets to be tedious constantly checking level, but if you don't, you risk getting to the end of a course and finding a misalignment that you will have to undo several courses to correct.

Note also that if you make a complete circle, you will inevitably have a course that has a keystone gap that is smaller that a full block. So consider placing a half-block (split one with a hammer and a rock chisel) on an end or where its not visible. On an arc wall, place them at the ends.

On an arc wall, the blocks at the end of each course will have to be sunk into the dirt on the outside edge so that the outside edge is not visible. This is will make a smooth transition and it will look less "tinkertoy".

If your slope is more that the height of a single block over the diameter of the arc, you probably want to line the backside of the block with a good quality landscape fabric. This will allow rainwater to pass through between the blocks and keep the soil retained. If you don't use fabric, each time it rains, a small amount of soil will leach between the blocks and collect in the corners which in unattractive and leads to weeds, block staining, and more maintenance. If you have a taller wall on a severe slope, line the backside with fabric and gravel.

Also, be careful to be consistent on the offset and setback of each course over the lower course. The geometric design of most castlewall blocks will make inconsistent course offsets look strange.

If you have blocks delivered, have them dropped as close to your work area as possible and somewhere you don't mind tearing up the grass as you will make repeated trips back and forth as you take blocks off the pallet and place them on the wall.

Good luck, stay hydrated, and remember, post LDPs when you're done.

[theboydoutdoors]

Everything 100%ttid said is spot on . He just left out that you can place landscape felt behind the block if you like to keep any backfill from washing through the cracks