Cinder blocks: clean ’em, paint ’em, stack ’em!

• Post Title: Concrete Thinking: How to Make Mod, Stackable Sculptures with Cinder Blocks
• Post Date: November 27, 2013

“What is garden art to you?”

That was the theme of the night during this week’s #GardenChat, the lively Twitter convo that happens every Monday from 6 to 7 p.m. PST. (Have you been? It’s a lively place to meet garden-minded people…)

That got us to thinking (and tweeting) about the ways in which Ryan and I like to add human-made flair to our yard. There’s the furniture Ryan designs, of course...but these days, we’ve been finding a lot of whimsy in...cinder blocks.

That’s right: good old-fashioned concrete masonry units. Their size, shape and negative space make them incredibly versatile to use inside a garden. Our concrete blocks measure 7-5/8 inches wide by 7-5/8 inches deep by 5-5/8 inches high and cost 79 cents each.

Find them at your local hardware store. Cinder blocks come in many different sizes, shapes, and can double as planters. Got a bunch of gourds to show off? Use cinder blocks to make a deconstructed jack o’lantern. Feeling down? Build ’em up into the throne for your spectacular self! You can, and should, paint them, primarily to seal them and make them cleanable. Instructions in a minute...

We’ve been moving cinder blocks around into various configurations for three years now in two locations within our garden. Our first location is beneath our citrus trees. We love the shadows that Ryan’s LED lights cast on this 40-block sculpture at night, but we’ve noticed that three years outdoors have left our blocks stained and dull.

It is nearly impossible to clean stains off of bare concrete blocks due to their porosity. Concrete blocks need to be sealed before they become cleanable. So we recently painted the 40 blocks of our first sculpture a clean shade of “Rustic Taupe” to match the newly renovated “citrus room” that Ryan built beneath our orange and tangerine trees. When we brought the blocks into the new room, we configured them differently and used them to support a new bench.

DIY Painted Cinder Block Sculptures:

1) Arrange concrete blocks for cleaning. We recommend resting each block at a slight angle (atop wood slats, for example) so that the blocks are not flat against the ground when drying. We added a dropcloth and used this arrangement for painting as well.

2) Wash the dirt from your cinder blocks with a strong jet of water. We used a pressure washer. This step can be skipped if the blocks are new and clean. A scrub brush and garden-hose sprayer could be substituted for the pressure washer. The cleaner the block, the better the paint will adhere and the longer it will last. We waited four hours for the blocks to dry before applying bonding primer.

3) Prime and paint the blocks. Bonding primer assures maximum adhesion of paint to concrete. We used Behr’s Concrete & Masonry Bonding Primer and Concrete and Garage Floor Paint from Home Depot for this job. Both are latex acrylic-based for easy cleanup. We used nap rollers to apply both products, making sure to thoroughly coat the inside of each block. We applied two coats of paint on top of one coat of primer. We waited a day between each coat. We found that a six-inch nap roller worked perfect for painting the inside of these blocks, which is very difficult to do with a brush. Each block took about two and a half minutes to paint. Forty blocks took about an hour and half! The second coat went a little faster.

4) Wait at least two days before arranging and stacking the blocks so that they do not stick together. Make sure your platform is strong and level.

Title: The Horticult | Address: thehorticult.com

Author: Chantal Aida Gordon and Ryan Benoit | From: La Jolla | Blogging since: March 20, 2013