Whether your property is a college campus, a corporate building, or Scrooge McDuck’s mansion, most elaborate landscaping designs will incorporate decorative concrete planters outside. And they need waterproofing.
We’ve had enough web visitors inquiring about waterproofing outdoor planter boxes to trigger me writing an article, so this blog will explain why you need to waterproof outdoor concrete planters and how you can go about waterproofing your outdoor planters.
3 REASONS WHY YOU NEED TO WATERPROOF YOUR OUTDOOR CONCRETE PLANTERS
- Plants Can’t Soil Themselves. Unlike toddlers, plants cannot soil themselves, so gardeners need to maintain careful control over their plants’ soil nutrients and pH levels. Concrete leeches alkaline, which creates a “sweet soil,” or alkaline soil, with a pH level above 7. This high pH level blocks nutrient access and stunts the plants’ growth, which waterproofing the concrete planers will prevent. Gardeners strive for acidic or neutral soil to ensure their plants keep growing and appearing healthy.
- Plants Can’t Hydro Flask Themselves. Dehydration is a very real problem when the planters aren’t waterproofed. After all, concrete is highly porous, so the moisture in the soil just seeps out via the concrete pores and evaporates quickly, dehydrating the plants’ roots.
- Concrete Can’t Heal Itself. The other issue with concrete porosity is that the concrete absorbs moisture and chemicals it plucks right out of the atmosphere, such as various salts, which will eventually cause cracks in the concrete, degrading–and ultimately destroying–the concrete planters.
Now that you know why, let’s talk about the “how” question. Seamless waterproofing is typically the industry standard for waterproofing outdoor planters.
WHAT IS SEAMLESS WATERPROOFING?
Seamless waterproofing is fluid-applied waterproofing, which creates a fast-setting moisture barrier that forms a seamless, fully bonded elastomeric skin–or membrane—that reinforces your concrete and prevents water or chemicals from intruding and impacting your concrete (and whatever is being housed within your concrete, which in this case, is plant life). Fluid-applied waterproofing is ideal for horizontal and vertical surfaces, for interiors and exteriors. There are two types of seamless waterproofing: hot-applied and cold-applied waterproofing.
WHEN DO I USE HOT-APPLIED VS. COLD-APPLIED WATERPROOFING ON AN OUTDOOR PLANTER? (Hint: What’s your clearance, Clarence?)
Sometimes the chosen form of fluid-applied material boils down to the contractor or architect’s preference. However, cold-applied waterproofing is typically the easiest to apply in a confined area like a planter. Hot-applied waterproofing needs clearance. It requires you to heat the material to 400°F (204.44°Celsius) and in a confined space, where those planters are sometimes up to 10 feet high, applying that hot material to a vertical concrete surface can endanger the waterproofing contractor.
HOW TO APPLY SEAMLESS WATERPROOFING MATERIAL ON YOUR OUTDOOR PLANTER: THE 4 STEPS
Step 1. Thoroughly clean the interior and exterior of your planter. You’ll want to remove any “efflorescence,” which is the white powdery substance you sometimes see on unsealed concrete. This is caused by exposure to salt and water solutions. Allow your planter to dry before you perform Step 2.
Step 2. Surface prime your concrete with the manufacturer’s specified primer so you reduce the likelihood of porosity, dust, pin-holing caused by entrapped air, or any moisture remaining in the concrete that will cause membrane blistering as your concrete cures.
Step 3. Spray or roller-brush your seamless waterproofing material onto the concrete’s surface until it’s thoroughly covered and there’s no longer any concrete visible through the material.
Step 4. Let your planters dry overnight in a well-ventilated area.
The good news is, once you’ve waterproofed your planters, the protection is long lasting unless your planter gets damaged. One way planter damage routinely occurs is when a landscaper or gardener bangs or scrapes it with a shovel, or actually drills holes into an outdoor planter for easier plant irrigation. This will impact the concrete and create moisture issues unless you reseal it.
For your convenience, we’ve linked our W. R. MEADOWS outdoor planter waterproofing materials below:
Accessory products include:
- BEM
- REINFORCING FABRIC HCR
- MEL-DRAIN (preferably MEL-DRAIN 9055-B)
If you have questions about waterproofing outdoor planters or anything related to concrete waterproofing, please call us at 1-800-342-5976 or email info@wrmeadows.com
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