What Are Cinder Blocks?<\/strong><\/h2>\n\n\n\n![\"Can](\"https:\/\/cohesivehomes.com\/wp-content\/uploads\/2021\/02\/Cinderblock-construction.jpg\")
<\/figure><\/div>\n\n\nCinder Blocks are basic concrete masonry units used in almost every construction project. These blocks come in various sizes and are referred to by their thickness. Standard sizes in the US include:<\/p>\n\n\n\n
\n- 4-inch blocks<\/li>\n\n\n\n
- 6-inch blocks<\/li>\n\n\n\n
- 8 inch blocks<\/li>\n\n\n\n
- 12 inch blocks<\/li>\n<\/ul>\n\n\n\n
These standard blocks are usually 16 inches long and 8 inches wide.<\/p>\n\n\n\n
Standard sizes in the UK include:<\/p>\n\n\n\n
\n- 440 x 215mm<\/li>\n\n\n\n
- 390 x 190mm<\/li>\n<\/ul>\n\n\n\n
As mentioned above, cinder blocks have holes in them to help with alignment and in some cases, the reason is actually to add soil or concrete within, provided the conditions are right.<\/p>\n\n\n\n
When Is It Safe to Fill Cinder Blocks?<\/strong><\/h2>\n\n\n\n![\"A](\"https:\/\/cohesivehomes.com\/wp-content\/uploads\/2021\/06\/A-cinder-block-being-picked-up-by-a-construction-worker-1024x682.jpg\")
A cinder block being picked up by a construction worker<\/figcaption><\/figure><\/div>\n\n\nIt is common practice to fill the holes of cinder blocks with rebar and then add concrete within to strengthen them<\/strong>. However, when doing so, it is important to take note of the climate you\u2019re working in. For example, if you\u2019re working during the winter season or even monsoon (not recommended, by the way), filling the holes is only going to create more problems for you.<\/p>\n\n\n\nIf, however, you\u2019re working in the middle of summer with little to no humidity, feel free to fill cinder blocks with soil or concrete.<\/p>\n\n\n\n
The reason filling is not recommended in most cases is that as the joining solution (mortar or concrete) you use to join cinder block solidifies, whatever you add within will diffuse the moisture inwards. Not only with that, even if you\u2019re adding soil, there will be moisture within. Concrete, of course, will be wet.<\/p>\n\n\n\n
This moisture<\/a> can take a year or two to dry out completely. This moisture will freeze over as the frost comes, leading to cracks in the cinder blocks. This is particularly dangerous when building retaining walls.<\/p>\n\n\n\nIf you are building a raised planting bed, it doesn\u2019t really matter if your cinder block develops cracks. What\u2019s the worst that can happen, right? But if you\u2019re working on a bigger project where the cinder blocks need to hold up immense weights, these cracks can be devastating.<\/p>\n\n\n\n
Can You Fill Cinder Blocks With Sand?<\/strong><\/strong><\/h2>\n\n\n\nThere is no doubt that sand is much easier (and inexpensive) to pour than anything else \u2013 even the more traditionally preferred sand and gravel mixture. When pouring sand, your goal should be to fill all voids and ultimately seal the bottom. There should be no place left for the sand to go because it won\u2019t be wet and therefore will have a tendency to flow.<\/p>\n\n\n\n
Try to compact<\/u><\/a> the sand as much as possible to ensure a sturdy \u2018infrastructure\u2019 for your cinder blocks to rely on. If done right and compacted enough (8-12 inches), you won\u2019t really need to pour concrete<\/strong>. This can be done in wet areas as well. Just make sure you don\u2019t overwater your mortar or joining solution.<\/p>\n\n\n\nHere\u2019s something that we have actually tried and has worked wonders for us:<\/p>\n\n\n\n
Build the wall or structure you are looking to build. Finish it and then drill two holes; at the top and the bottom of the wall (atop the holes you\u2019re trying to fill). Place a screen or filter at the bottom hole such that only water can flow through it, not sand. <\/em><\/em><\/p>\n\n\n\nPump a sand\/water mixture and wait. The water will carry the sand into every nook and cranny and compact it. Use a pump to make sure it\u2019s compact. Let the water drain out and you\u2019ll only have sand left behind!<\/em><\/em><\/p>\n\n\n\nCan You Fill Cinder Blocks with Dirt?<\/strong><\/strong><\/h2>\n\n\n\nDirt isn\u2019t really recommended for cinder block fill<\/strong>. It can retain a lot <\/em>of moisture and therefore impact your structure\u2019s integrity. We would suggest that you go with sand instead of dirt if possible.<\/p>\n\n\n\nCan You Fill Cinder Blocks with Gravel?<\/strong><\/strong><\/h2>\n\n\n\nFilling cinder blocks with gravel alone \u2013 especially pea gravel \u2013 is known as a lazy-fill. Yes, it works, and it increases the wall\u2019s mass and strengthen<\/strong>s<\/strong> it<\/strong>. This is great for places like Florida or Spain (sub-humid). However, the wall won\u2019t really insulate<\/strong>.<\/p>\n\n\n\nSo, basically, you\u2019ll get a sturdy wall, but you\u2019ll most likely hate that particular wall during the winter season.<\/p>\n\n\n\n
Instead of using just gravel, we would recommend you use a mixture of sand and gravel,<\/strong> which actually takes care of that issue. The sand seeps into the nooks and crannies left by the gravel while the gravel adds mass into the wall and strengthens it. You get the best of both worlds with very little extra cost, considering that sand doesn\u2019t really cost that much.<\/p>\n\n\n\nJust remember to add water into the sand when adding so that the mix compacts well. Give the mix about 2-3 days so that water drains out and only then seal the exit.<\/p>\n\n\n\n
When mixing, for every 3 bags of gravel, add 4 bags of sand. However, the mix is entirely up to you, depending on the degree of strength-to-insulation you are looking for.<\/p>\n\n\n\n
Can You Fill Cinder Blocks with Foam for Insulation?<\/strong><\/h2>\n\n\n\n![\"Spraying](\"https:\/\/cohesivehomes.com\/wp-content\/uploads\/2021\/06\/Spraying-foam-insulation-into-a-ground-area-1024x682.jpg\")
Spraying foam insulation into a ground area<\/figcaption><\/figure><\/div>\n\n\nThe answer to this is a resounding YES<\/strong>. People fill cinder blocks with foam regularly for insulation. It isn\u2019t the best idea out there, but it is perhaps the next best thing after a sand and gravel mix. However, we would recommend doing so only when the summer season is at its peak.<\/p>\n\n\n\nIt is quite common for the foam to be a bit too compressed at one spot and thus not really dry out completely. When this happens, you will start seeing wet patches across your wall. This mostly happens at the bottom of cinder block walls and ends up damaging the paint on that particular area.<\/p>\n\n\n\n
We recommend you not seal the top for a few hours \u2013 or at least a day \u2013 after filling it with foam to let it dry out completely.<\/p>\n\n\n\n
Filling cinder blocks with foam is ideal for insulation, not to mention how easy it is. However, the venture can get really, <\/strong>really <\/em><\/strong><\/em><\/strong>expensive, depending on how large the wall is<\/strong>.<\/p>\n\n\n\nCan You Fill Cinder Blocks with Concrete?<\/strong><\/strong><\/h2>\n\n\n\nIf you are working in the middle of summer, are a patient DIY-er (or professional), or are building a retaining wall, you simply can\u2019t go wrong with filling cinder blocks with concrete<\/strong>. The goal of adding concrete within cinder blocks is to strengthen the wall.<\/p>\n\n\n\n
<\/figure><\/div>\n\n\nCinder Blocks are basic concrete masonry units used in almost every construction project. These blocks come in various sizes and are referred to by their thickness. Standard sizes in the US include:<\/p>\n\n\n\n
- \n
- 4-inch blocks<\/li>\n\n\n\n
- 6-inch blocks<\/li>\n\n\n\n
- 8 inch blocks<\/li>\n\n\n\n
- 12 inch blocks<\/li>\n<\/ul>\n\n\n\n
These standard blocks are usually 16 inches long and 8 inches wide.<\/p>\n\n\n\n
Standard sizes in the UK include:<\/p>\n\n\n\n
- \n
- 440 x 215mm<\/li>\n\n\n\n
- 390 x 190mm<\/li>\n<\/ul>\n\n\n\n
As mentioned above, cinder blocks have holes in them to help with alignment and in some cases, the reason is actually to add soil or concrete within, provided the conditions are right.<\/p>\n\n\n\n
When Is It Safe to Fill Cinder Blocks?<\/strong><\/h2>\n\n\n
\nA cinder block being picked up by a construction worker<\/figcaption><\/figure><\/div>\n\n\n It is common practice to fill the holes of cinder blocks with rebar and then add concrete within to strengthen them<\/strong>. However, when doing so, it is important to take note of the climate you\u2019re working in. For example, if you\u2019re working during the winter season or even monsoon (not recommended, by the way), filling the holes is only going to create more problems for you.<\/p>\n\n\n\n
If, however, you\u2019re working in the middle of summer with little to no humidity, feel free to fill cinder blocks with soil or concrete.<\/p>\n\n\n\n
The reason filling is not recommended in most cases is that as the joining solution (mortar or concrete) you use to join cinder block solidifies, whatever you add within will diffuse the moisture inwards. Not only with that, even if you\u2019re adding soil, there will be moisture within. Concrete, of course, will be wet.<\/p>\n\n\n\n
This moisture<\/a> can take a year or two to dry out completely. This moisture will freeze over as the frost comes, leading to cracks in the cinder blocks. This is particularly dangerous when building retaining walls.<\/p>\n\n\n\n
If you are building a raised planting bed, it doesn\u2019t really matter if your cinder block develops cracks. What\u2019s the worst that can happen, right? But if you\u2019re working on a bigger project where the cinder blocks need to hold up immense weights, these cracks can be devastating.<\/p>\n\n\n\n
Can You Fill Cinder Blocks With Sand?<\/strong><\/strong><\/h2>\n\n\n\n
There is no doubt that sand is much easier (and inexpensive) to pour than anything else \u2013 even the more traditionally preferred sand and gravel mixture. When pouring sand, your goal should be to fill all voids and ultimately seal the bottom. There should be no place left for the sand to go because it won\u2019t be wet and therefore will have a tendency to flow.<\/p>\n\n\n\n
Try to compact<\/u><\/a> the sand as much as possible to ensure a sturdy \u2018infrastructure\u2019 for your cinder blocks to rely on. If done right and compacted enough (8-12 inches), you won\u2019t really need to pour concrete<\/strong>. This can be done in wet areas as well. Just make sure you don\u2019t overwater your mortar or joining solution.<\/p>\n\n\n\n
Here\u2019s something that we have actually tried and has worked wonders for us:<\/p>\n\n\n\n
Build the wall or structure you are looking to build. Finish it and then drill two holes; at the top and the bottom of the wall (atop the holes you\u2019re trying to fill). Place a screen or filter at the bottom hole such that only water can flow through it, not sand. <\/em><\/em><\/p>\n\n\n\n
Pump a sand\/water mixture and wait. The water will carry the sand into every nook and cranny and compact it. Use a pump to make sure it\u2019s compact. Let the water drain out and you\u2019ll only have sand left behind!<\/em><\/em><\/p>\n\n\n\n
Can You Fill Cinder Blocks with Dirt?<\/strong><\/strong><\/h2>\n\n\n\n
Dirt isn\u2019t really recommended for cinder block fill<\/strong>. It can retain a lot <\/em>of moisture and therefore impact your structure\u2019s integrity. We would suggest that you go with sand instead of dirt if possible.<\/p>\n\n\n\n
Can You Fill Cinder Blocks with Gravel?<\/strong><\/strong><\/h2>\n\n\n\n
Filling cinder blocks with gravel alone \u2013 especially pea gravel \u2013 is known as a lazy-fill. Yes, it works, and it increases the wall\u2019s mass and strengthen<\/strong>s<\/strong> it<\/strong>. This is great for places like Florida or Spain (sub-humid). However, the wall won\u2019t really insulate<\/strong>.<\/p>\n\n\n\n
So, basically, you\u2019ll get a sturdy wall, but you\u2019ll most likely hate that particular wall during the winter season.<\/p>\n\n\n\n
Instead of using just gravel, we would recommend you use a mixture of sand and gravel,<\/strong> which actually takes care of that issue. The sand seeps into the nooks and crannies left by the gravel while the gravel adds mass into the wall and strengthens it. You get the best of both worlds with very little extra cost, considering that sand doesn\u2019t really cost that much.<\/p>\n\n\n\n
Just remember to add water into the sand when adding so that the mix compacts well. Give the mix about 2-3 days so that water drains out and only then seal the exit.<\/p>\n\n\n\n
When mixing, for every 3 bags of gravel, add 4 bags of sand. However, the mix is entirely up to you, depending on the degree of strength-to-insulation you are looking for.<\/p>\n\n\n\n
Can You Fill Cinder Blocks with Foam for Insulation?<\/strong><\/h2>\n\n\n
\nSpraying foam insulation into a ground area<\/figcaption><\/figure><\/div>\n\n\n The answer to this is a resounding YES<\/strong>. People fill cinder blocks with foam regularly for insulation. It isn\u2019t the best idea out there, but it is perhaps the next best thing after a sand and gravel mix. However, we would recommend doing so only when the summer season is at its peak.<\/p>\n\n\n\n
It is quite common for the foam to be a bit too compressed at one spot and thus not really dry out completely. When this happens, you will start seeing wet patches across your wall. This mostly happens at the bottom of cinder block walls and ends up damaging the paint on that particular area.<\/p>\n\n\n\n
We recommend you not seal the top for a few hours \u2013 or at least a day \u2013 after filling it with foam to let it dry out completely.<\/p>\n\n\n\n
Filling cinder blocks with foam is ideal for insulation, not to mention how easy it is. However, the venture can get really, <\/strong>really <\/em><\/strong><\/em><\/strong>expensive, depending on how large the wall is<\/strong>.<\/p>\n\n\n\n
Can You Fill Cinder Blocks with Concrete?<\/strong><\/strong><\/h2>\n\n\n\n
If you are working in the middle of summer, are a patient DIY-er (or professional), or are building a retaining wall, you simply can\u2019t go wrong with filling cinder blocks with concrete<\/strong>. The goal of adding concrete within cinder blocks is to strengthen the wall.<\/p>\n\n\n\n