Foam density is the weight of cured polyurethane per cubic foot, expressed in pounds per cubic foot (PCF or lb/ft3); it is the primary indicator of a foam’s strength and intended use.
In depth
As a rule, higher density means higher compressive strength. Residential foams sit around 2.5 to 3 lb/ft3, general commercial foams around 4 to 4.5, stabilization foams around 5, and heavy-infrastructure foams around 6 to 6.5. Contractors choose density by weighing the load the slab carries against the need to avoid overloading weak soil.
Density also interacts with reaction time and expansion: a denser foam is stronger, while a slower-reacting foam travels farther to fill voids, so formulation is chosen for the specific problem.
How Acme applies it. Acme documents the density of each foam it runs (RR-201, RR-401, RR-501, and RR-601) and selects among them per project rather than using one product for every job.
Related terms: High-Density Foam, Compressive Strength, Expansion Ratio, Polyurethane Foam
Frequently asked questions
What is a typical foam density for concrete lifting?
Around 4 lb/ft3 is a common everyday density for commercial and residential lifting, delivering roughly 100+ PSI of compressive strength.
How is foam density related to strength?
Higher density generally produces higher compressive strength, which is why heavier loads and infrastructure call for denser formulations.