Pre-cast concrete blocks are strong and versatile, allowing construction crews to quickly build foundations and full basements with less work than is involved with pouring a cast-in-place structure. However, the convenience of these blocks is balanced out by their tendency to develop leaks and let moisture enter the foundation or basement. Discover five complications that interfere with waterproofing concrete blocks to have the best chance at getting a watertight seal after your first attempt.
The mortared joints between individual blocks cause the majority of leaks and moisture problems in concrete block structures. While mortar is a durable material, it eventually cracks and crumbles away to create a pathway for water to flow through into the basement or foundation. It's not all that easy to repair cracks and gaps in these mortar layers because the opening is often hidden deep inside the block rather than on the surface where you can reach it with caulk or mortar. Repairing badly damaged mortar can cost thousands, or even tens of thousands, of dollars.
Bowing Due to Pressure
Concrete block walls are often just as strong as those poured in place, but all concrete is susceptible to lateral pressure. Concrete may be a very strong material against pressure pushing straight down on it, such as your home's walls and roof, but it is relatively weak against pressure coming from the side, such as wet soil pushing against foundation walls. Concrete blocks are more likely than poured slabs to bend and bow inward. Bowed walls crack and lose their mortar in the joints, resulting in lots of entry points for water. A bowed wall also loses its strength and can eventually collapse and leave your home sinking into the ground.
Almost all of the masonry blocks designed for basement and foundation use are designed with two to three hollow openings in the center of each block. This reduces overall weight without sacrificing much strength, but it can create serious leakage problems at the same. When the top run of hollow blocks is left open by accident or on purpose, vertical channels are created that run to the bottom of the wall. Moist air and even water itself can enter the basement or foundation walls and fill up the space, resulting in slow leaks that don't appear to correspond to specific rain storms. A leak anywhere further down the wall also allows moisture to build up inside these hollow cores, making it hard to pinpoint exactly where a leak begins.
Some types of concrete blocks chosen for their aesthetic value are more prone to absorbing water like a sponge and transferring it to the interior of your basement or foundation. Split-faced blocks feature a rough and uneven exterior that mimics natural stone. These blocks are strong enough to use for foundation building with only a single layer, creating a direct path between the extra porous exterior and the interior of your basement. Water travels through the pores quickly to leave your walls wet on a regularly basis without a single crack or damaged joint in sight. These split-faced blocks must be sealed with extra care if they're to be used safely for foundations and basements.
Finally, the window openings built into concrete block walls often leak more readily than those designed into poured walls. Since the construction crew must work around the sizes of the blocks rather than creating a completely custom opening, it's harder to flash and seal around the window opening. The drain tiles set into the tops and bottoms of window wells are also particularly prone to blocking up and directing water into the basement or crawlspace instead.Share
30 November 2016
When you are in the middle of trying to renovate your space, you might be tempted to remove that dated crown molding or trash those antique faucets. After all, since you want your space to look new and minimalistic, who needs that hand-carved ceiling panel or that ornate archway? Unfortunately, if you make the wrong choices, you might end up throwing away valuable or irreplaceable materials. To help you to avoid this mistake, my blog is filled with ideas for how to fix up your home or business without damaging remaining artifacts. By protecting the natural design, you might be able to create a unique space that you will treasure forever.