Rainwater Harvesting Tank Installation – Part 1

Forms for the Rainwater Tank Concrete Base

I made the forms from 1×8’s. They will be held in place with 1×2 stakes. Temporary 5 inch blocks help with spacing the inner and outer forms. More stakes are driven in and then the blocks removed.

I attached 2×4’s to these boards to screw the stakes to. I’m not a forming contractor and I’m sure there’s a simpler way to do this but, this is what works for me. I roughly position the outer forms and clamp the corners together. Then run in some screws. This worked well to create the basic box. Then I squared and levelled it as I was driving in stakes to hold it in place.

It’s funny what you discover when you film yourself working on a project. I seem to have a furniture or woodworkers approach to what is really rough carpentry. I’m not a carpenter or a builder. I simply have a passion for building things. And, I don’t have an issue at all with constructive criticism or tips from you builders out there. We can all benefit here so I welcome your feedback.

With the outside form boards in place I can make the inner walls that will create the curb. I wasn’t sure how well the forms would come apart on the inside as I was worried that they would bind against each other.

Building the Inner Walls of the Form

So I made the inner forms walls in two pieces. I cut the end off the inner form wall at a 45 degree angle on one end.

Then I reattached it with a mending board.

I figured this will make stripping the forms easier as this piece can pivot away from the corner. I’m not sure if I really needed to build them this way but it only took a few minutes to do this.

This idea came about as I was working on a square concrete planter form. It seems that it can be challenging to disassemble the inside of a closed space. More on that project in a future video.

Installing the Inner Walls

I clamp and screw the inner forms together. And attach the 5 inch spacer blocks. That worked great. It help suspend the inner form at almost level as I pounded in the stakes. I ended up using two blocks at each corner.

Once these were removed I coated the inside of the form with vegetable oil.

I bent four 10 foot lengths of rebar, wired them together and suspended them from wire so they would stay in the center of the curb during the pour.

Suspending the Rebar on Wire

Leave a Comment

Your email address will not be published. Required fields are marked *

Shopping Cart
Scroll to Top