Dry-mix Aminoplast Resins vs. Core-Fill 500™ Masonry Foam Insulation: A Reality Check

Dry-mix masonry foam insulation products and Core-Fill 500™ are not the same. Quality assurance for dry-mix masonry foam insulation is problematic because the product requires precise job site handling and mixing and added water free of impurities, yet dry-mix products are commonly installed by job site laborers who do not have the proper training and experience to correctly prepare the resin. Another issue is that the dry-mix resins have less plasticity than Core-Fill 500™, which is manufactured and delivered in liquid form directly to certified installation contractors who have extensive training in handling and installing the product. Reduced plasticity leads to shrinkage in the installed insulation, which allows air infiltration through the block wall.

The building supply distribution channel issue

Dry-mix masonry foam insulation is typically sold through wholesale distributors and building supply outlets. Consequently, these products are often installed by laborers who do not have special training or experience in handling, mixing or installing the product. Dry-mix masonry foam insulation resin is shipped in 55-pound bags, like pre-mix concrete. The following instructions are from one such bag:

“Clean drums with a scrub brush and hot water. Beware that the water supply at some new building sites can contain enough oil residue sealants or coatings to be completely detrimental to the resin. Using the paddle mixer to stir, slowly add the three 55-pound bags of resin powder. Stir until all the powder is wet and dissolved. Let stand overnight but not more than one week.”

Additional instructions require that once in full dilution, the resin should be used within 24 hours to meet all published specifications. And prior to installation, the walls must be dry, with no visible wetness of the exterior surface. The product should be protected from excess moisture during the initial 24-hour period after installation.

Does this sound like the proper product for use in hot and humid climates like the Southeast United States--especially Florida?

If these specific directions are not followed precisely, you could end up with walls that look like the image above. The bleed-through visible in the image is evidence of foam that was not mixed properly. And in a relatively short period of time, the foam in the block wall above will shrink. At that point, thermal resistance will be lost, along with the foam’s ability to stop air infiltration.

Dry-mix masonry foam insulation has less plasticity.

Once the dry-mix manufacturers have produced a liquid resin, they spray the resin onto a flat surface and send it through an oven dryer. During this process, water and other key liquid ingredients are evaporated. The residual resin film is then pulverized into small pieces and bagged. After water is added to the mix at a job site, important ingredients--most notably, the structural plasticizers--never fully regain their plasticity. Shrinking of the final product is inevitable, which allows hot, moist air to circulate through the cores of the concrete block. Shrinkage is an inherent problem for all dry-mix resins. Impurities in the unfiltered job site water supply are an additional problem.

Core-Fill 500™ liquid resin is different.

Tailored Chemical avoids the plasticity and water quality problems described above by shipping Core-Fill 500™ only in liquid form. As you might expect, shipping a product in liquid form in tanker trucks is not as cost-effective as shipping a solid concentrate in bags. But based upon Tailored Chemical’s extensive 30-year plus experience with the product, liquid shipping and certified installation contractors are essential to ensure a consistent product with the necessary performance after installation.

Each raw material used in the production of Core-Fill 500™ must complete a certification process before it can be used in production. Every drop of water used during the manufacture of Core-Fill 500™ is first filtered through state-of-the-art purification equipment.

Tailored Chemical’s culture of quality assurance is not limited to masonry foam insulation. As of 2005, the company manufactured about 80% of the glue used by school children in North America.1 Naturally, manufacturing an adhesive used by millions of children requires a culture of zero-defects quality assurance.

So how do you choose?

Masonry foam insulations are not generic. The manufacturing methods, installation restrictions and warranties differ significantly. Thermal performance based only upon the standard thermal properties of ingredients in a masonry insulation is useful for project planning and design but not for evaluating competing products. In a perfect world, you would be able to compare the independently tested and certified performance of competing masonry insulation products and that would be that. Such testing would measure the thermal performance and air infiltration rates for standard insulated block and precast concrete assemblies, and would include accelerated exposure to heat and cold to determine plasticity when installed and shrinkage over time.

Unfortunately, just as insulation contractors need not be licensed contractors, so too there is no independent testing of random samples of installed masonry foam insulation products. And even if there were, the results might not mean much for dry-mix resins mixed at a jobsite by untrained laborers. You can mitigate these risks by choosing a manufacturer, product and an exclusive, certified installation contractor chosen by the most sophisticated architects and project owners. When long-term performance and quality assurance matter more than the lowest initial cost, choose Core-Fill 500™ masonry foam insulation.


  1. Source: Advertising Age, August 1, 2005. Tailored Chemical manufactures the glue used in the leading brand of “white glue” and glue sticks under contract for the brand owner.