For the last century, masons and building construction experts have been using almost exclusively a substance called Portland cement in their creations. The advantages were obvious when it was first created: it dried faster, was more waterproof, and was harder than it's predecessor, hydraulic lime.
But as it turns out, Portland cement isn't ideal in all circumstances. Many builders are just learning that it has its problems -- and that the old-school hydraulic lime combats most of those same problems.
You'd think that if Portland cement is more waterproof than hydraulic lime, it would be better for waterproofing your house, right? That bit of intuition fails, however. It turns out that hydraulic lime's semi-permeable nature is good
for keeping your building dry. That's because bricks and stone actually absorb tiny amounts of water from rain and humidity. Hydraulic lime wicks the moisture out
of the blocks, keeping them dry, which in turn makes them less likely to crack and let water in to your home.
Portland cement is indeed harder than hydraulic lime -- but that's not a good thing. Think about it this way -- which is harder, a plate or a chicken? Which would be more likely to survive a hit from a baseball bat? The chicken might be pretty unhappy about it, but it wouldn't explode into a thousand pieces like the plate would. That same principle applies here. Hydraulic lime is way better for chimney repoining, Nassau County
experts say, because
it's more flexible.
Portland cement dries faster because it has salts in it that speed the drying process. But what it took scientists decades to realize is that the same salts cause Portland cement to start degrading the instant it finishes getting hard. Meanwhile, hydraulic lime takes a lot longer to dry, but rather than particles of salt drifting through the substance harming it, lime particles drift through the hydraulic lime. When the substance gets wet, the lime actually moves toward the source of the water and helps patch the hole -- it's a self-healing process.
With all of these huge advantages, it's clear that waiting a little while longer for the hydraulic lime to dry is a small price to pay. Almost every chimney pro Nassau
homeowners ask either promotes hydraulic lime, or has yet to learn about it.
Chimney Rebuilding, Chimney Repair