12/17/2023 0 Comments Skim coat block wall![]() However, during periods of wind-driven rain, water will be easily absorbed into porous surfaces, increasing the chances of surface efflorescence and lime staining. It can be a losing battle because cinder blocks are water-permeable!Įxterior, above-grade cinder block walls (retaining walls, decorative walls) are not often subject to hydrostatic water pressure complications. It may take a number of years, but once the exterior waterproofing coatings and damp-proofing membranes deteriorate, the cinder blocks will be on their own to fight against negative side water pressure. If you have a wet basement constructed with cinder blocks, they are more likely to leak water compared to poured concrete foundation walls. Water can easily pass through the cracks in the mortar joints and leach through the capillaries and pores, causing basement walls to dampen. When the hollow cores of the blocks retain groundwater, the thin walls offer little resistance against hydrostatic water pressure, and the cinder blocks dampen and leak. ![]() Damp cinder block walls are frequently noticeable after inclement weather conditions wind-driven rains, heavy rainfalls, water-soaked ground, saturated zones, and high-water table areas. Making matters worse, only a thin wall (1-3/4 inch) separates the hollow cores of the cinder block from filling up with water and leaching out. High-quality, newly poured concrete foundation walls (8-10″ in thickness) are impermeable to water (0.4-0.3 perms). ![]() Heavyweight concrete blocks are semi-permeable (5 perms) and less so when the hollow cores are filled and packed with a slurry mix of concrete (about two perms). Cinder blocks are classified as permeable to water and water vapor (+10 perms). Why Cinder Block Basement Walls Leak WaterĪ cinder block is significantly more porous compared to standard concrete blocks and poured concrete. Lightweight blocks cannot be used in retaining walls or exterior building walls because they readily seep water. Haydite Blocks – Another example of an expanded shale product.Split-faced Blocks – Have a rough, stone-like texture on one face of the block instead of a smooth face.Lightweight CMUs – Gravel is replaced with shale or clay expanded at extreme temperatures which makes the blocks much lighter at 22 to 28 lbs.This is why they are often used in interior non-moisture construction or outdoors for barrier walls, hardscapes, and fences. However, cinder blocks are more subject to moisture, water seepage, radon gas, salt deposits, and efflorescence (white powdery residue) problems because of their high porosity. ![]() Compared to a heavyweight concrete block, a typical cinder block weighs only 26-33 lbs. There are builders that prefer cinder blocks because they are much easier to work with. Modern cinder blocks are usually made with volcanic pumice instead of cinder unless there is a nearby coal-fired power station or cement kiln to supply pulverized cinders or fly ash. “Cinder block” is an archaic term from the time when power plants and coke ovens in steel mills produced huge amounts of “cinders” from burning coal. Lower-density blocks may use industrial wastes, such as fly ash or bottom ash as an aggregate instead of the sand or fine gravel used to make true concrete. The typical high-density concrete block (8 x 8 x 16 inches with two cores) weighs 36-42 lbs. Compared to typical structural concrete, they are made with a higher percentage of sand and a lower percentage of gravel and water for a stiffer mixture that holds its shape when removed from the block mold. Standard (high-density) concrete blocks are made from cast concrete – Portland cement, sand, and gravel. ![]() CMUs may look similar, but there are big differences among them! Employing reinforcement bars and filling the hollow cores with concrete results in strong structural walls. CMUs are used for the construction of load-bearing foundation walls, basement walls, partition walls, exterior walls, retaining walls, and non-load-bearing partition walls. Concrete blocks and cinder blocks, as well as split face blocks and lightweight blocks, are all referred to as CMUs (concrete masonry units). ![]()
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