concrete collar

The concrete collar is a key component of your pond as it acts as a reference point for the entire build. Unfortunately, many are unable to see the importance of it and the "do I really need one" question pops up quite often during consults

The collar is the first step in building a proper pond and it's one that shouldn't be skipped. Remember, it can be looked upon as the foundation of your pond much like a house needs a foundation to be structurally sound
Page Summary:
  • The collar is a perimeter ring or beam of concrete around the pond
  • The collar sets level
  • The collar defines the shape
  • A stable shelf for your stone
  • Is the foundation of your pond

What is a Concrete Collar

In the simplest terms a collar is a concrete ring or beam of concrete around the perimeter of the pond. This provides a stable base support for stone and allows you to set the rock in the water at a desired depth. Without this support shelf, rock can sink, tilt and even fall over into the pond. Waterfalls in particular, require a larger pad with footings below the frost line in order to stand the test of time. The waterfall pad is best integrated into the collar and all completed in 1 pour

1 bag of concrete does about 2 feet of collar for the typical pond. Use a good amount of rebar. Consider obtaining a mixer if you have more than 25 bags to mix. Do not make a sloppy mix - it is not as strong. You may have to leave a gap/indentation in your collar for the skimmer. Let the concrete dry slowly - keep it wet with a hose. Use a laser level. Dump the soil into the middle of the pond, your excavator can pull it out
  • This stone is about to fall right into the pond
  • Some of the ugliest stone and stone work I have ever seen
  • Here we have dug out the trench to form the concrete
  • Footings should be used under waterfalls or any heavy stone

I remember one pond we built we found a large stone in the side wall while excavating. It was interfering with the shape of the pond shell and needed to be removed. Without the collar in this instance, the whole side wall would have crumbled in. We were able to remove it, pack it, and retain the integrity of the shape

On numerous consults, resistance to collar installation has been met. In one particular case, the client did not heed my warnings. The following Spring I returned to see a collar had be installed. Laughingly, the client said "you were right". There had been several collapses and everything had to be rectified

  • This pond has quite a slope for its small size
  • It can be quite a lot of digging for the collar install
  • Rebar is key for structural strength
  • The finished collar provides a level shelf for your stone work

insulated concrete forms [ICF]

  • Insulated concrete forms work great for pond collars - much faster than building forms
  • Concrete is poured into the forms
  • ICF comes in a 16" height and various widths - 6 inch, 8 inch etc

Repairing a Collapsing Waterfall and Installing a Concrete Collar