Can water seep through cinder block walls?

Author: Ezra Morissette III  |  Last update: Sunday, November 30, 2025

Like other foundations, cinder block foundations can succumb to water seepage. This is a problem that no homeowner should ignore. The problem only gets worse over time. It is therefore important to deal with the seepage as soon as you notice it.

How do I stop water from seeping through concrete blocks?

Waterproofing Paint: Use specialized waterproofing paint designed for concrete surfaces, which can help prevent moisture penetration. Fill Cracks and Joints: Use epoxy or polyurethane sealants to fill any cracks or joints in the concrete. This helps prevent water from seeping through these openings.

Are cinder block walls waterproof?

A cinder block is significantly more porous compared to standard concrete blocks and poured concrete. Cinder blocks are classified as permeable to water and water vapor (+10 perms).

How do you stop water seeping through walls?

Applying hydraulic cement on the walls will also prevent any excess moisture from coming through the walls. The next steps, if you don't mind digging, would to apply a water proof liquid membrane on the outer walls and the top of the footer. You basically paint on 2-3 coats and you're set.

How to stop water seepage in concrete wall?

Seal the cracks in the walls

They permit moisture to seep into your building's structure, resulting in damp spots and seepages in the walls. Filling in cracks with wall crack filler is thus one of the best ways to stop water from leaking through walls.

How to Waterproof Concrete Block, Best Waterproofing for Concrete Block

Is it normal for water to seep through concrete?

Concrete is already a porous material. This means that water could find its way through your concrete by itself. But, if you have cracks or cove joints that aren't sealed properly, water will use those openings to enter your foundation.

Why is water seeping through my wall when it rains but no leak?

Over time, bricks can crack, and mortar can erode, creating pathways for water to enter. Pay special attention to any visible cracks, gaps, or crumbling mortar. Gutter and Downspout Inspection: Faulty gutters and downspouts can direct water towards the wall instead of away from the property.

Why is moisture coming through my block wall?

Wall structure: Excess airflow can bring in water vapor. That's why it's important to balance drying and drainage without encouraging spore growth. Make sure the structure is airtight enough to restrict airflow and vapor. This can help keep moisture and mold growth at bay.

What to do if water leaks through a wall?

What Should I Do if I Have a Water Leak Behind a Wall?
  1. Turn off the water supply.
  2. Turn off the breaker that supplies power to the electrical outlets and wiring near the leak.
  3. Hire a professional to locate the leak source.
  4. Allow professionals to drain and dry the area.
  5. Have the leak repaired.

Will Drylok stop water?

DRYLOK® Original Masonry Waterproofer will withstand 10 pounds of hydrostatic pressure (PSI), equivalent to a wall of water 22 feet high, and is GUARANTEED TO STOP WATER.

Can water go through cinder block wall?

The concrete blocks used to build the foundations are hollow. These spaces permit water to seep through and collect within the walls.

What is the life expectancy of a cinder block wall?

If the conditions are right, concrete building blocks have a lifespan of 100 years or more. This makes them a very durable building material.

Do cinder block walls need to be sealed?

Concrete block walls provide a great surface for stucco to adhere to without the need for sealants. In fact, sealing may actually make it more likely that water will get trapped between the block wall and the stucco coating, making long term adherence almost impossible.

How to detect a water leak in a concrete wall?

How to detect water leaks in concrete walls
  1. Discoloured patches of wall.
  2. Hot-to-touch patches.
  3. Puddles of water/wet surroundings where the leak has cascaded down the wall.
  4. Bubbling, which is more apparent if the concrete wall has been treated by a coating or paint.
  5. In severe leaks, the wall might curve or warp.

What is the best sealer for cinder blocks?

Siloxa-Tek 8500

Best used to preventatively seal concrete blocks and cinderblocks that have not had any moisture issues. This waterproofing sealer will help to prevent water from seeping through concrete blocks and cinderblocks.

Should you fill cinder blocks with concrete?

Filling each block will provide it with a greater surface area and increased weight. Heavier blocks sit more securely, ensuring the interlocking pattern will remain fixed and tight.

Does homeowners insurance cover water leaks in walls?

Under most standard home insurance policies, if water damage occurs suddenly or accidentally from a source inside your home, such as a busted pipe, it will likely be covered by your homeowners insurance. If the water comes from outside your home, it will not be covered by your standard policy.

How do plumbers find water leaks in walls?

Once you know you have a leak, you'll need to hire a plumber. But how do plumbers find leaks? Plumbers use moisture meters and determine the area of the wall with the highest moisture levels. Sometimes, leaks are located using infrared cameras, which point out the coolest (and wettest) areas behind the walls.

How much does a water leak behind a wall cost?

Fixing an exposed pipe in a crawl space or basement is $150 while repairing a leaky pipe inside a wall starts at $150 and can go up to $350 or more. A pipe in the wall behind a kitchen cabinet will cost $500; if the faulty pipe is in a ceiling, it can cost $700 to $2,500.

Does water damage cinder blocks?

As concrete is a porous material, the resultant pooling (entrapment) of water within the cinder-block wall will, eventually, accelerate the deterioration of the blocks to the point of failure and, with the passage of time, lead to far greater repair costs and potentially damage the structural integrity of sections of ...

How do you fix water seeping through walls?

Interior plumbing fixes: A leak in the plumbing inside walls requires cutting the wall open, finding the exact spot where the leak is occurring, fixing it, patching the wall, and then sanding, priming, and repainting it. Most people don't have the equipment and experience for this, so hiring a pro is best.

How do you stop damp seeping through walls?

Preventing Damp Walls
  1. Condensation – ensure good ventilation and minimise creating moisture internally.
  2. Good outdoor maintenance to your property.
  3. Monitor external vegetation to reduce the risk of it damaging masonry and render.
  4. Don't plant large plants near your house as roots may damage foundations or damp proof courses.

Why is water seeping through concrete wall?

High hydrostatic pressure outside the foundation can cause water to seep through solid concrete walls. It will also force water into the basement along the crack between the floor and the walls. Cracks that form in walls also provide pathways for water to enter the basement.

Why is my wall wet inside but no leak?

There are several causes for damp patches appearing on interior walls including damaged guttering, cracked roof tiles and more commonly condensation.

Is water leaking from wall an emergency?

Most homeowners know a burst pipe by a rush of water leaking from a wall or ceiling, but it's not always that dramatic. Either way, it's still a plumbing emergency. A burst pipe can release gallons of water, which can compromise the structural integrity of your home, such as collapsed ceilings and weakened walls.

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