Foam replacing concrete? Turns out that polyurethane foam can actually supplement concrete. It comes in a bag, and you just mix up parts A and B. A mere 2 ½ lbs. of foam can replace 60 lbs. of concrete. Sounds much lighter, and as you might've guessed, much cheaper too. These slow rise foam bags are around $10 to $15 - much cheaper than the average concrete price. The real question is is it as strong as concrete? This foam can withstand 3000 to 4,"000 pounds of force without shearing. Watch the full video as Kyle Stumpenhorst of Rural Renovators joins Matt Risinger to test it out. See for yourself what this new foam alternative is all about!