Parging is a popular strategy for protecting an ICF home’s exposed perimeter at grade — right where the waterproofing ends and the exterior veneer begins.
Yet sometimes parging can fail over time due to cracks or spalling.
The majority of parging failures usually happen either because of an improper application or because an installer unfortunately took some money-saving shortcuts.
In this post, you’ll learn the correct procedure for applying parging to ICF walls, and also find out a few alternative methods for perimeter protection.
Why Parging Failures Happen on ICF Walls
Probably most parging failures happen because step of installing protective fiberglass mesh was skipped when applying the parging material.
To apply parging with a fiberglass mesh the installation process requires a second step and additional costs.
So, to save time and money, unfortunately some installers may simply apply the parging material and skip the reinforcement mesh step.
Unfortunately, this practice can result with a parging material that is fragile and more vulnerable to damage.
Years after the home is built, these issues can become a headache for the homeowner. With time, the unreinforced parging material (such as DuRock B2000) can crack due to damage from grass mowing equipment, hockey sticks and pucks, baseballs hitting the wall, and other regular wear-and-tear.
These cracks can then allow moisture to seep through deep into the wall, and the subsequent freeze-thaw cycles eventually damage the bond between the parging material and the ICF foam. And once the bond loses its integrity, the parging can eventually spalls off the wall.
How to Prevent Parging Failures
To prevent parging failures, you should apply the parging material AND the waterproofing membrane beneath it properly. Below, you’ll find the recommended steps for installing waterproofing and parging correctly.
Waterproofing Installation Technique
- Terminate the waterproofing at the right level: The waterproofing membrane should be terminated at least 2 inches above grade.
- Fasten the top of the membrane: In extreme hot and cold climates, it’s best to fasten the top of the waterproofing membrane. However, sealing the top of the membrane is the best additional insurance to protect you from parging failure even in moderate climates. You can use either of the following options to seal the top of the waterproofing layer:
- A caulking product like Resisto sealant for damp and dry surfaces
- A membrane strip such as Soprema Grip F
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Proper Parging Application Technique
Applying the parging material properly can save the future owners of your homes a great deal of headache. Below are the four key steps you should follow when applying parging to prevent its failures in the future.
- Overlap the top of the membrane: You should always overlap at least the top 2 inches of the waterproofing membrane. This step keeps the membrane securely attached to the ICF and prevents moisture from getting in.
- Apply a skim coat first: It’s a good idea to first apply a thin skim coat of parging. Then, you can embed fiber mesh into it for greater strength.
- Embed fiber mesh: Integrate pre-cut pieces of fiber mesh into the first coat of parging. Doing so will strengthen the coating and prevent spalling.
- Apply a second coat: With the first coat and the fiber mesh installed, you can now apply the second (and final) coat of the parging material.
Parging Alternatives For Perimeter Protection
Parging is a common approach to perimeter protection; however, it’s not the only suitable strategy. Here are some alternatives to parging you should consider for an ICF home’s perimeter protection:
- Fiber cement panel
- Prefinished metal
- Pressure-treated plywood
Wrapping It Up
Parging failures can happen and their root cause often lies in corner cutting and improper installation.
If you want the parging coat to withstand wear and tear over the years — and keep your customers happy — it pays to follow the simple steps we’ve discussed above when applying waterproofing and the parging coats.
And remember, there are other materials you can use instead of parging for your ICF homes’ perimeter protection.
