Foundation Protection: Is Your Dimple Sheet Up for the Job?

The Situation:

Proper foundation protection is critical to keeping basements dry. Deciding on a dimpled membrane for a foundation’s protection system is the right choice. Dimpled membranes have many advantages over other systems. In the words of Waterproof Magazine, “They can easily be installed over virtually any foundation type: poured concrete, concrete block (CMU), insulated concrete form (ICF) or preserved wood foundations (PWF).”

A dimpled membrane offers many benefits that sprays simply do not. Dimpled membranes provide an even application, factory-controlled quality, and the ability to bridge foundation cracks. This means no water intrusion, optimal comfort and healthy living spaces for homeowners, and fewer warranty claims and call-backs for builders. The dimples also create an air gap between the membrane and the foundation, which removes hydrostatic pressure from any incidental water getting behind the dimpled membrane, allowing it to flow freely to the perimeter footing drain.


The Problem:

You choose a product based on decent specs, and the product appears to be of good quality, but how can you know if the product you’ve chosen is truly up for the job? When selecting a dimpled membrane, you should consider the following:

  • What type of protection do you believe you’re getting?sagging-dimple-sheet
  • Do you know the best/recommended way to install or secure the dimpled membrane to the foundation?
  • What accessories are provided, and how do they affect performance?
  • Might the product sag or tear? How do you avoid this?
  • Would you recognize the signs of a problem with your foundation protection?
  • Do you know the damages that can result from using an inferior dimpled membrane, or from an improper installation?
  • Do you know the proper recourse should an issue/damages arise?

The type of protection the homeowner can expect depends a great deal on the quality of the dimpled membrane you select. The dimple height, sheet thickness, and compressive strength vary between manufacturers. As is true in many industries, when it comes to building supplies, you get what you pay for. Why are some membranes cheaper than others? Because the quality is inferior.





The Solution:

Choose a dimpled membrane with proven durability, a selection of any and all required accessories, and an in-depth installation manual.

Start with using the most durable dimpled sheet on the market. It’s common for dimple sheets to be made of thermoplastics like high-density polyethylene (HDPE). What’s not common across brands is the formulation and/or composition of the dimple sheet. Using all-recycled HDPE saves cost and makes the product “green,” but also makes the dimple sheet more vulnerable to aging and stress-cracking, which leads to collapsing of the dimples and failure of the foundation protection. To prevent that, a co-extruded dimple sheet with an embedded layer of recycled HDPE between two outside layers of new HDPE is the best option. This mix gives the membrane a higher stress-crack resistance and compressive strength and helps to maintain the membrane’s integrity and durability, meaning you don’t have to worry about sagging or tearing, which lead to moisture intrusion.bad-dimple-sheet-installation

Speaking of sagging and tearing, there are a couple of ways these can occur with a membrane. Proper installation is your first move in preventing sagging and tearing. With a dimpled membrane, installation can be done as soon as the forms are removed. The weather won’t dictate when you can apply it, since it’s not temperature dependent.

Fasteners – and their placement – make a big difference in membrane installation and functionality. Using a multi-stud fastener over single-stud fasteners provides advantages such as superior holding power to prevent tear-down at fastening points during backfill. Once the membrane is rolled out along the wall, be sure to install the fasteners at appropriate intervals. For rolls greater than 7’ (2 m) in height, an extra row of fasteners is suggested in the middle of the membrane.

The Front Runner:proper-dimple-sheet-installation

DELTA®-MS is the dimpled membrane others try to imitate. We set the standard. In an apples-to-apples comparison, professionals will choose DELTA®-MS. And because of this, the only way for imitators to sell their product is by downgrading quality in an attempt to gain some edge; typically, in pricing. But it is that very edge that ends up costing the consumer so much more in the long run. Downgraded products provide downgraded protection – and can downgrade your reputation as a builder.

The DELTA®-MS foundation protection system is the most durable dimpled membrane on the market, keeping foundations dry for the life of the building. It is a co-extruded product, made of 60% recycled and 40% new materials – recycled material inside and virgin HDPE layers outside. All three layers also contain specific additives to protect the polymer against aging from elements such as oxidation and UV.

Last, DELTA®-MS is supported by an extensive certified-installer program. This certification provides the confidence, reliability, and trust to ensure materials are properly applied, and buildings are properly protected. The certified-installer program allows builders and contractors to provide customers a 5-year leak-proof warranty and 10-year material warranty.


Click here if you’d like to learn more about our DELTA Academy Certified-Installer Program. Read more about the best dimpled membrane on the market here, and click here for more information on how to keep foundations/basements dry.