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Should Concrete Blocks Be Filled?

Concrete blocks are vital materials for achieving ideal structural strength in every masonry project. However, correctly constructing the project is also critical to attaining the best outcome for your project. So should you fill concrete blocks' cells? We thoroughly researched this topic, and here's what we uncovered below.

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You can certainly fill or pour the cores in the concrete blocks, especially in wall projects. However, you can refer to your local building code for further building requirements. Your local building code will always dictate the specific standard for pouring your concrete block cores.

If you want to learn more about the ideal mixing ratio for your filling materials, stay with us! We provided below the answer to the commonly asked questions relating to this topic.

Is It Necessary To Fill The Cores Of The Concrete Blocks?

Concrete blocks are widely common in wall applications but it is also essential in some construction setups. In essence, pouring the cores of the concrete blocks is necessary to increase the wall's compressive strength.

This will always depend on your local building code, but if happens you live in South Florida, you should comply with Florida Building Code (FBC). As this particular area is prone to a High Velocity Hurricane Zone (HVHZ). 

In addition to filling the concrete block cores, you should also consider the thickness of the concrete block web. This also plays a vital factor in attaining satisfactory structural performance when filling their cores.

According to the American Society for Testing and Materials (C90), you should use a concrete block with a web thickness of 3/4 inches (19 mm). This will ensure you fill all cores evenly in between the web of the concrete block.

What Do You Fill Concrete Blocks With?

Construction worker builds brick wall

Generally, concrete block structural designs differ in size but include interior cores or cells.

The voids in the concrete blocks are specifically manufactured to be filled with concrete or mortar. You can also fill the concrete block core with another concrete finish compound that is rated for wall use.

Which Filling Material Lasts Longer: Concrete Or Mortar?

Concrete comes from a mixture of gravel, cement, sand, and water. It has a low water and cement mixing composition and a lighter consistency, making it far more durable and long-lasting than mortar.

Moreover, concrete with reinforcing steel bars will also boost the structural strength of your walls. The strength of concrete can go to 4,000 utmost pounds per square inch (PSI).

If concrete curing requirements are properly followed, you can expect it to last 100 years. If concrete structural integrity is always exposed to naturally damaging elements, otherwise, its expected lifespan is around 50 years.

In contrast, aside from gravel, mortar has a similar mixing ratio as concrete uses. It is denser compared to concrete due to its higher water and cement mixing ratio.

Mortar strength is around 750 PSI, which makes it last about 20 to 30 years.

Which Is More Cost Effective: Concrete Or Mortar?

Using concrete to make your concrete block wall stronger is more expensive than mortar. This is due to the number of materials that are necessary to achieve stronger concrete mixing products.

Note that cement is the most costly material that is essential for concrete. Yet, you can buy concrete at around $110 per cubic yard. After all, it is the most cost-effective and practical material available you can use.

Given that it is very durable and has a notably long lifespan, it's worth opting for concrete than mortar.

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How Long Do Concrete And Mortar Mixtures Start To Cure?

When you're mixing your filling materials for the concrete blocks' void spaces. It is also critical to know how long both concrete and mortar mixture starts to cure. This will allow you to practically save tons of your budget.

As already cured or hardened concrete or mortar while still in the mixing process is already useless. According to experts, it would take up to about 24 hours for the concrete to be completely cured.

However, if you opt for mortar, you should only mix it with a sufficient batch as per your project. As mortar consistency starts to fade after 1 ½ to 2 ½ hours after your initial mixing.

If you notice that the mortar begins to cure after 2 ½ hours, remix it immediately to retain its ideal consistency. So be wise to mix your filling materials to avoid unnecessary costly waste.

How Do You Fill Cores In Concrete Blocks?

Assuming that you're using concrete to fill the cores in concrete blocks. Starting your job assuring that everything is already set well is a great idea. Now include to prepare the following things you'll need:

Tools to prepare to fill concrete blocks

  • Bucket.
  • Shovel.
  • Gloves.
  • Trowel.
  • Wheelbarrow.
  • Safety goggles.

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Given that all necessary mixing preparation has already been taken care of. You can now begin applying your concrete to the cores in your concrete blocks.

Worker building cinder block wall

Here's how you do it:

  1. Shovel some concrete into the wheelbarrow to conveniently transport the concrete near the construction site.
  2. Don't over-stress yourself to put too much concrete in the wheelbarrow.
    • This is to avoid any mishap while you're transporting your concrete.
  3. Once you've enough concrete nearby the location of the project. You can now dip some concrete using your bucket.
  4. Use your cement trowel to gently apply and level the concrete to the cores of your concrete blocks.
  5. There you go, repeat this process until you finally fill all the concrete block spaces.

Pro tips: The key to successfully doing this task, is to have a handy assistant.

Can I Fill The Concrete Block Walls With Insulation Foams?

You may not be so familiar with filling your concrete block walls with insulation foam. But you can certainly pour it with some insulation foam materials. Among the insulation foams you can use are:

  • Spray foam.
  • Foam boards.
  • Injection foam.
  • Polystyrene beads.
  • Loose-fill insulation.

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It is necessary to insulate your concrete block walls to block air or moisture to penetrate inside the walls. As concrete block materials are porous which are notably high in porosity properties.

In other words, concrete blocks like to absorb natural elements that cause damage to your walls over time. That is why it is essential to fill the void of concrete blocks in your walls to prevent intrusion issues.

How Long Will Concrete Block Walls Last?

Professional masonry filling empty cavities with concrete

Concrete block walls have an extremely long lifespan of more than 100 years.

The patching compound or filler enhances the outer structural integrity of the walls. Finishes such as epoxy, latex, and alkyd increase the overall strength of concrete block walls.

The embedded steel rods inside the cells of the concrete block will slowly deteriorate because high alkalinity concrete protects against corrosion.

What Is The Benefits Of A Concrete Block House?

Concrete building structure made from prefabrication system

Over the past century, concrete block construction materials have been the choice of many houses in the U.S. This is because concrete block serves many benefits in overall house building investment.

The following are the five beneficial features of concrete block houses:

It Promotes Energy Efficiency

Using a concrete block along with ideal insulating materials develops an airtight and high thermal insulation envelope. As a result, your home achieves a nine percent more energy-saving percentage than concrete wall setups.

Ensures Healthy Environment

Concrete blocks prevent mold and pests from infiltrating the walls. Additionally, concrete block houses do not pose a health risk to occupants.

Unlike the wooden type of houses that produces dust which triggers allergies, eye irritation, and other side effects associated with wooden dwellings.

This is because wood certainly rots as time passes. Consequently, dust will lay on your furniture and could be inhaled at any time. This is what causes the dwellers to develop a respiratory illness.

It Reduces Sound Penetration

Its compact structural design along with the filler materials and insulation layer helps to block 1/4 of outdoor noise.

High Thermal Resistance

Blocks made of concrete stop the rapid spread of flames during a fire incident. However, this doesn't imply that it is completely fireproof. The added safety feature of refractory mortar will protect your house from intense fire.

It ensures your house to withstand extreme heat about 2,000° F, far stronger than traditional cement and mortar which only resist a temperature between 600°F to 700°F.

Maintenance Cost Effective

Another beneficial factor with concrete block homes is they can slow down the progression of rust. This will allow you to lower your total expenses associated with the house repair maintenance.

To Wrap Things Up

Concrete block cores are meant to be filled with ideal pouring materials. Doing so will help your building project attain the best structural result. So follow our advice and guidelines to properly and correctly fill your concrete blocks.

If you find this article helpful, please read also our other related post below:

Can You Cement Or Pour Concrete Over Brick?

Can You Pour Concrete Over A Utility Easement?