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Do You Need to Fill Concrete or Cinder Blocks? (Answered)

Cinder blocks or concrete blocks are an essential part of the construction. It gives the structure. The stronger the blocks, the more durable the construction is. Depending on the construction some use cinder blocks and some use concrete blocks. Those blocks are both different.

Following the below tips regarding concrete or cinder blocks and filling them may help you to proceed faster.

Do you need to fill concrete blocks?

You can fill concrete blocks if they have unnecessary holes. Depending on the construction, you should fill concrete blocks. While using hollow blocks, you can fill them. It will make them stronger and more sturdy. You should also fill hollow concrete blocks if you are running pipes through.

Using concrete blocks is suitable for construction. They are strong and sturdy. Fully concrete blocks are perfect if you want a soundproofing wall. It even gives proper insulation. Hollow concrete blocks are easier to carry. At the same time, they are used in certain places and decrease the cross-sectional area.

Even filling the hollow concrete is better if you are putting pipes or steel. It will give space and hold the pipes in place. But many decide to fill them and it has the best consequences. Some of the reasons why you should fill the concrete block are given below.

Strong and sturdy:

Filling the concrete blocks makes them strong and gives strength to the wall. Hollow concrete blocks are not used in many spaces. They are used for building fences and base foundations. Later filled with either concrete, mortar, or foam. The filing helps the concrete blocks to provide insulation too.


Holes or hollow blocks are not strong themselves. Unnecessary holes in the concrete blocks can create instability. Moreover, this can act as the entrance for the bugs. The moisture trapped in the blocks can lead to cracks. Rather, the filling is better as it will keep the blocks stable.

Do you fill these concrete blocks?

There can be many concrete blocks that needs to be filled. So, let us find out which of them needs to be filled.

Hollow concrete blocks:

Hollow concrete blocks are not meant to be filled. They are made hollow and used only in certain places. If you want to run pipes through the wall or put steel, you should use hollow concrete blocks. Later you can fill the concrete block. Hollow concrete blocks are easier to carry.

Even the cross-sectional area is reduced and also less expensive. Even though hollow concrete blocks are not required to be filled, filling the hollow surfaces may give the blocks more strength.

Holes in concrete blocks:

Holes in the concrete blocks should be filled with either a mortar mixture or cement. Filling the holes will give better stability to the concrete and the construction will become more sturdy. Unnecessary holes shouldn’t be left in the concrete.

Unnecessary holes may lead to the bugs entering and living. It may hamper the stability of the concrete too.

How to fill a concrete block wall?

Flying a concrete block wall is necessary as you can not leave them open. The filling can be done both by hand or by machine. Using a machine might seem easier as it won’t require you to put in any effort. To fill the block wall, follow the steps one by one.

Clean the surface:

Cleaning the surface is always required. Do not let any dirt fill the hollow parts. Rather only wiping away the dirt would work effectively.

Put the mixture:

You can either use a mortar mix or a concrete mixture to fill up the concrete block wall. Use a machine and pipe and fill them. Use the pipe to fill up the gaps and hollow surfaces. Put the mixture until the blocks are fully filled. Make the surface even with a scraper and put the excess mixture away.

Do you need to fill cinder blocks?

Filling cinder blocks is necessary as it will give the block stability. Moreover, cinder blocks are not used in all places as they are not strong enough. Filling them may lead to strengthening cinder blocks. If you want to leave the cinder blocks unfilled, it will not be a good one for a wall.

Cinder blocks are hollow blocks of concrete mixed with other materials. These blocks are particularly used for fences and where you do not need to put heavy loads. Filling the cinder block is still different from full concrete blocks. Carrying the blocks is easier and reduces the resistance as well. Below reasons are also considered to fill the cinder blocks.


Cinder blocks are filled with foam and gravel too. In order to give proper insulation to the wall, it is necessary. Yet do not leave any moisture to the wall as it can damage the blocks. Proper insulation is necessary during the days of summer. Sand and gravel mixture is better in that case.


Hollow blocks are not strong compared to a full concrete block. On the other hand, full concrete blocks get cracks easily rather than hollow blocks. Filling the hollow blocks will provide them with more strength to hold up the weight. The wall will also become durable by filling the hollow parts.

Are cinder block foundations filled?

Yes, cinder block foundations are filled. Foundation bases are mostly cinder blocks. Filling the blocks would rather increase the strength of the wall.

When cinder blocks are filled with concrete, they get the appearance of the concrete block. Well, concrete blocks and cinder blocks are totally different. Even filling can not provide a full structure of concrete blocks to the cinder blocks. The cinder blocks are hollow in nature.

As a result, the cross-sectional area is reduced and once filled can hold more weight. Yet, they are not as good as concrete blocks. You can fill the cinder block foundations with concrete, mortar, or even foam. Depending on what type of wall you want.

For a strong and sturdy wall, filling it with a mortar mixture or concrete will bring the best. Yet, insulation can not be provided by this.

What do you fill cinder blocks with? Can you fill cinder blocks with these?


You should never fill the cinder blocks with dirt. You do not want your cinder block to turn into garbage. Dirt will provide no strength to the wall. It will rather do bad.


Sand can also be used to fill up the cinder blocks. Sands are easier to carry and cost less. You can put sand on it but not the wet one. Only put the dry sand. Wet sand would rather lead to damage if the cinder blocks.


Using gravel to fill up the cinder blocks can be done as well. Gravels would make the cinder blocks heavy and sturdy. Rather a mixture of sand and gravel would provide better stability.


Foam is usually better for filling cinder blocks. It provides great insulation throughout the wall. Moreover, it doesn’t let the excess heat enter the wall. Yet adding foam is a bit expensive. For cheap, you can use sand and gravel to fill the blocks.


You can definitely fill the cinder blocks with concrete. It is the most suitable one. Concrete will make the cinder block more strong and sturdy. As a result, the cinder block will remain for a long time and can hold more weight.


Apart from concrete, the second suitable way to fill up the cinder blocks is with a mortar mixture. The mortar mixture is good for filling though doesn’t provide much strength compared to concrete. Yet, mortar shouldn’t be too wet. Otherwise, the moisture may take a long time to dry.

How to fill cinder blocks?

Filling cinder blocks is no different from filling the concrete wall. Well, the differences might be in the materials you want to put in the holes. Manually doing it is easier. Certain steps should be followed in order to fill the blocks and are given below.

Stabilize the cinder blocks:

Well, you already would have put the blocks in straight light by attaching each block with a mortar or concrete mixture. If you want to put pipes or pillars, you can put them too.

Fill the blocks:

You can fill the blocks by putting a mortar mixture or concrete mixture directly into them. If you are using pillars in the cinder block, fill it with the concrete mixture to the top. It will hold the pillars in place. While using foam, you should drill a hole and put the foams using a pipe.

Final Thoughts

Overall, filling the concrete or cinder blocks helps to give the wall strength. Apart from strength, it provides stability and proper insulation to the wall. Cinder blocks are easy to carry and used in places where heavy loads are not put on. A filling will also ensure the durability of the wall.