What is Bentonite?
What is Bentonite? I get asked this question at least 3 to 4 times a week, especially when working with new (though also with existing) clients in Drumheller. Although it is one of the most discussed topics in Drumheller real estate, it is also one of the most misunderstood and, for this reason, I will be addressing it in this weeks blog topic.
Bentonite is a clay that is largely composed of Montmorillonite, which is mostly a hydrous aluminum silicate known for its unique characteristic of swelling when placed with water. There are two types of bentonite: sodium and calcium. For our discussions of bentonite and its effects on Drumheller homes, we will be discussing sodium bentonite.
Sodium bentonite is noted for its affinity to swell when mixed with water. Bentonite absorbs nearly five times its weight of water when fully saturated, and its "swelling" properties when wet are what cause issues with homes it effects.
Bentonite clay has widely been documented for its uses in the engineering industry as a sealant and for drilling fluid material; however, very few articles document what considerations have been made for construction on it. As it relates to construction in Drumheller, all of the builders are well aware of how to work with bentonite. Consumers, however, still do not completely understand this soil and automatically create a negative image in discussing it.
Dealing with bentonite requires understanding that the combination of water and this clay results in "swelling," creating problems in basements. Today's construction practices allow builders to ensure the soil under the basement slab remains dry with advanced weeping tile and sump pumps. In the past, the absence of such tools to avoid water getting under the basement slab has created severe cracking and heaving of basement slabs. Today, many of the past issues with bentonite have been resolved with these tools, simple positive grading and drainage away from the home’s foundation.
Without positive drainage, weeping tile, and sump pumps, water will often find its way down the foundation wall around the footing and under the basement slab. Severe cracking and heaving of basement slabs is a result of water mixing with bentonite under the slab of the house. The hydraulic force of this bentonite mixture pushing up on the slab results in serious issues. Without any space to expand to, the slab cracks under the hydraulic pressure or heaves upward, essentially bending the concrete (until it cracks) upward to alleviate this pressure.
As mentioned earlier, proper weeping tile with sump pumps are valuable tools to preventing water from getting under the slab. Equally important, in my opinion, is having proper grading and drainage away from your property. Ironically, this is where bentonite and its ability to work as a sealant will work to your advantage. If you have seen water running off the hills in Drumheller, you will know bentonite can create an excellent water barrier when graded away from you home to prevent moisture from even getting to the weeping tile. Another important component in ensuring water drains away from your home is having your down spouts down during rain. Now I know this seems simple. But I can not tell you how many times I have driven up and down streets with basement issues during heavy rain and seen rain spouts still attached to the house.
Bentonite is a reality of living in Drumheller and, although it has a higher content in areas close to the hills, it does effect all properties in the valley with the exception of Riverview district. Understanding it will allow you to ensure you work with its positive characteristics in maintaining a square, dry basement.
Bentonite is a clay that is largely composed of Montmorillonite, which is mostly a hydrous aluminum silicate known for its unique characteristic of swelling when placed with water. There are two types of bentonite: sodium and calcium. For our discussions of bentonite and its effects on Drumheller homes, we will be discussing sodium bentonite.
Sodium bentonite is noted for its affinity to swell when mixed with water. Bentonite absorbs nearly five times its weight of water when fully saturated, and its "swelling" properties when wet are what cause issues with homes it effects.
Bentonite clay has widely been documented for its uses in the engineering industry as a sealant and for drilling fluid material; however, very few articles document what considerations have been made for construction on it. As it relates to construction in Drumheller, all of the builders are well aware of how to work with bentonite. Consumers, however, still do not completely understand this soil and automatically create a negative image in discussing it.
Dealing with bentonite requires understanding that the combination of water and this clay results in "swelling," creating problems in basements. Today's construction practices allow builders to ensure the soil under the basement slab remains dry with advanced weeping tile and sump pumps. In the past, the absence of such tools to avoid water getting under the basement slab has created severe cracking and heaving of basement slabs. Today, many of the past issues with bentonite have been resolved with these tools, simple positive grading and drainage away from the home’s foundation.
Without positive drainage, weeping tile, and sump pumps, water will often find its way down the foundation wall around the footing and under the basement slab. Severe cracking and heaving of basement slabs is a result of water mixing with bentonite under the slab of the house. The hydraulic force of this bentonite mixture pushing up on the slab results in serious issues. Without any space to expand to, the slab cracks under the hydraulic pressure or heaves upward, essentially bending the concrete (until it cracks) upward to alleviate this pressure.
As mentioned earlier, proper weeping tile with sump pumps are valuable tools to preventing water from getting under the slab. Equally important, in my opinion, is having proper grading and drainage away from your property. Ironically, this is where bentonite and its ability to work as a sealant will work to your advantage. If you have seen water running off the hills in Drumheller, you will know bentonite can create an excellent water barrier when graded away from you home to prevent moisture from even getting to the weeping tile. Another important component in ensuring water drains away from your home is having your down spouts down during rain. Now I know this seems simple. But I can not tell you how many times I have driven up and down streets with basement issues during heavy rain and seen rain spouts still attached to the house.
Bentonite is a reality of living in Drumheller and, although it has a higher content in areas close to the hills, it does effect all properties in the valley with the exception of Riverview district. Understanding it will allow you to ensure you work with its positive characteristics in maintaining a square, dry basement.
