Friday, September 5, 2014

Concrete Borders for Trees

Creating concrete borders around the trees in our back yard

Difficulty Level (Easy, Medium, Hard, Insane):

Since we've had the opportunity to buy a second lot behind our house in 2009 we have steadily been planting a couple of trees each year bringing us up to almost 20 as of now. A few years back I put some black mulch around the trees but it never really looked right. I've always wanted to put a little extra professional touch on our landscaping and have been doing some research as to how to best do that.

I've concluded that the best cost/benefit solution would be to pour my own concrete borders around the trees and fill the inside with mulch. This would serve (at least) three purposes:

1. Create a neat edge around the tree
2. Simplify mowing the lawn around the mulch
3. Upgrade our landscaping

A few days ago I decided to finally start on this project. The first thing I did was take a metal rod that I reclaimed from an old patio umbrella (I think), bent one end to go around the small tree trunks and taped some marking spray at the other end. I made one of those contraptions 24" long (creating a 48" diameter) and one at 30" (creating a 5 foot circle).

After I mowed the lawn and sprayed the circles on the freshly cut lawn, I used my circular saw with a custom blade to cut through the top 2-3 inches of sod along the spray painted lines. Next, I used a pick axe to cut off a 6 inch strip of sod to a depth of about 2-3 inches.

Lastly, I cut a 2 inch strip of 1/8" particle board and formed a circle to give me the proper height and make it a bit rounder than if I just did it by eye.

After I poured the first batch though I realized that the 1/8" particle board pretty much disintegrated after being exposed to the wet concrete. The ring itself turned out ok but since there was no way to re-use the strips and the set-up was fairly time consuming I had to come up with a better solution.

I ended up buying 40' of 1.5" x 1/8" flat iron and had a shop put a bend in it for $5 cash. Then I welded some pieces of angle iron to the metal so I could hook them into pieces of wood to hold up the metal ring.

After some fiddling around and cutting up some spacers to keep the border nice and consistent I mixed up the concrete, poured and troweled it. Then, after about an hour or two I used one of the rubber stamping mats I had created when I did my concrete driveway back in 2009 to stamp some texture into the concrete.

The next day I removed the border and cleaned up the edges a little bit. A day after that, I cut the expansion joints with a diamond blade and my angle grinder, sealed the concrete with some tinted concrete sealer (decra-seal) that was left over from the concrete driveway project.

The last thing to do was to cut out the sod on the inside of the concrete ring, place some landscaping fabric down and fill it up with black mulch.

I am very pleased with how it turned out but I still have 18 more to go so that should keep me busy for the next 3 weeks!


My first attempt at creating a form out of 1/8" hardboard
Another closeup. You can see the metal wire I used to tie the borders to the supporting pieces of wood
Welding the hooks to one half of the small ring
Close-up of the hook used to hold up the ring
I used 6 for the small ring and 8 for the larger ring
Laying it out on the shop floor to ensure it's nice and round
Close-up of how I joined the two halves by using one piece of supporting wood to hold the rings up and together
Another close-up of a regular support
Metal spacers to keep the rings nice, round and parallel
A close-up of the spacer
Another view
The cherry tree almost ready for the concrete
Spacers in place, ready for the concrete
After the concrete was placed and trowled out
A view from a little farther apart
After the concrete has cured for two days and the forms have been removed
You can see the texture really nice in this picture
A close-up of the finished concrete
Using a 3' diameter piece of tar paper folded in half, in half, and in half again to give 8 equal parts to space out the expansion joints evenly (and yes, I aligned them with the cardinal directions)
After the expansion joints were cut
A view of the whole tree

A view from the upstairs window

Angle grinder
MIG welder
Pick axe
Wheel barrow
Circular saw
Extension chords
Measuing tape
Ear muffs
Protective eye wear
Diamond blade for angle grinder
Table saw
Side cutters

Marking spray
40' of 1.5" x 1/8" flat iron
4" of 1" x 1" angle iron cut into 1/8" pieces for hooks
Scrap wood
Scrap laminate flooring
Gravel, sand & cement for concrete

Metal forms: about $30.0
Each tree ring: about $5.00 for the concrete

Making the metal forms: about 2hrs
Each tree ring: about 2-3hrs

No idea how much it would cost to have a landscaping company make these but I'm guessing at least $200 per tree which would come out to about $4000 in total.

Love it, makes it SO much nicer and neater to look at now!