In the last bubbling boulder post, I walked you through digging the boulder pit. After the pit is dug, there are still a few more steps in preparation for the boulder.
(I had some awesome photos that would have been perfect for this post, but I either accidentally deleted them, or they were destroyed when my computer crashed last year.)
1. Create a gentle slope in the ground leading into the pit.
With your shovel, create a gentle slope in the ground around the pit leading into the pit. This step is optional. If you choose to do what we hope to do, you’ll want this incorporated into the design.
We plan on installing a spraying system to mist the river rocks. Unless you have a monster-sized water pump (so that the water gushes through the boulder like a geyser) most of the river rocks won’t get wet. The boulder definitely will get wet, but not a lot of the surrounding rocks.
The river rocks have a deep, rich, beautiful color when wet. I’m constantly out there with the water hose spraying the rocks. On hot days the rocks only stay wet and colorful for 10 minutes, maximum. Can you tell I’m a bit particular?
2. Add a 1 inch layer of sand in the pit.
The sand will help eliminate irregularities, and create a soft layer for the pond liner. This is important because of the next few steps.
3. Add sand to the sloped sides.
I ended up using lumber to help keep the sand in place.
4. Place two (2) layers of pond liner in the pit.
To determine the pond liner size needed, you’ll need to take into account the surface area of the following:
- the bottom of the pit,
- the walls of the pit, and
- a minimum 18 inches (preferably a lot more) on all sides.
Do NOT skimp on the pond liner!! If you want to save money there are plenty of other areas to do that (smaller boulder, etc.). You’ll quickly regret only using one layer of pond liner.
Even though this stuff is thick and heavy duty, within a few months of our installation, the bottom layer of our pond liner had a leak. It was probably a tree root that punctured the liner. However, with having two layers, everything’s fine.
5. Place a horse mat (or similar material) on top of the pond liner.
You want a soft, thick material. I was told an old carpet remnant might work, but John found a horse mat, made of recycled rubber, on sale. I prefer the horse mat.
6. Place cinder blocks in the pit.
The boulder will be placed on a few cinder block columns. The blocks serve a couple purposes: they raise the bottom of the boulder to ground level, and allow more space for water under the boulder.
The sand under the pond liner and the horse mat (or carpet remnant) on top of the pond liner prevent punctures in the pond liner from the excessive weight of the boulder on the somewhat sharp-edged cinder blocks.
Stack the blocks so that the top of the blocks are almost level with the above ground. Orient the blocks so that the block holes are vertical, not horizontal. The blocks are strongest when used this way.
That’s pretty much it. You’re now ready for a bobcat to lower your boulder onto the cinder blocks.
I’ll walk you through the finishing touches of the river rocks, etc. in the next post.
If you’re curious where we’re at in this series, and what’s left, here’s what we’ve already covered:
The Bubbling Boulder Unveiling
Bubbling Boulder – The Price Tag
6 Tips When Shopping for a Bubbling Boulder
Bubbling Boulder – Choosing the Location
Bubbling Boulder – Digging the Pit
Before-Bubbling-Boulder-Delivery Prep Work (Today’s Post)
Here’s what’s left:
Boulder Placement And The Finishing Touches
Electrical And Plumbing Installation