The Problem

If your home was built between the years of 1983 – 2016 in northeastern CT, your home’s foundation may have a big problem lurking… excessive pyrrhotite which may cause your foundation to literally crumble apart. Sounds like a nightmare, right? It can definitely feel like one to homeowners affected by this problem. 

Many homeowners first notice there might be a problem because of cracks, usually horizontal ones compared to vertical ones which can be normal settling cracks. These cracks grow larger over time in a pattern resembling a roadmap (aka “mapping”), often accompanied by discoloration on the basement walls (efflorescence) or some water seeping in. Some people notice a window that fits tighter than it used to, or a door that won’t stay half way open and always swings open or closed. If a foundation is compromised, it can’t do its job properly and the house itself shifts with those changes. Eventually, left unrepaired, the deteriorating foundation will very likely eventually cause the house to collapse.

The Epicenter 
Let’s start at the beginning and explain what causes this crumbling foundation problem in eastern CT. The epicenter of this crisis is directly related to concrete that was supplied by J.J. Mottes Company, a company located in Stafford Springs, CT. It operated from 1983 – 2016 and delivered concrete to towns within an approximately 30 mile radius from Stafford Springs, CT, which includes as many as 50 Connecticut towns. We now realize this radius also extends to areas of southeastern Massachusetts as well. This quarry used aggregate in its concrete that contained pyrrhotite, a mineral that can cause mayhem in a home’s foundation.

To understand exactly what makes this a problem, let’s take a few minutes to understand concrete.

Concrete = Cement + Water + Aggregate

Cement = a combination of lime, silica, alumina, magnesia, sulfur trioxide, alkaline, iron oxide, and calcium sulfate. These “ingredients” are generally extracted from limestone, clay, marl, shale, chalk, sand, bauxite, and iron ore. 

A mix of cement and water makes a mixture that’s called a slurry.

Sand, gravel, and crushed stone, aka aggregates, are added to the mixture.

Through a chemical reaction called hydration, the cement paste hardens and becomes strong. One key to making a strong concrete that will last for a long time depends on how much water goes into the concrete mixture and this amount is determined by a ratio. If there’s too much water, the concrete will be weaker and may cause, for example, more cracking than usual even in a “healthy” foundation. 

What makes concrete stronger or weaker? 
High-quality concrete is produced by lowering the water-cement ratio as much as possible without sacrificing the workability of fresh concrete, allowing it to be properly poured, worked with, and cured.

How do they know if a batch is properly mixed? It’s possible to check this by what’s called a “slump test” which measures the flowability of the mixture. When concrete is poured, it needs enough water to pour out of the cement truck and to properly fill the foundation forms but not so much flowability that it’s too watery and therefore weaker. In Connecticut, slump tests are required for commercial construction but not for residential construction. Here’s a nice video that shows how a slump test is done. 

Back to our story
Now that you understand the “ingredients” in concrete, let’s talk about the source of the aggregate used to produce the concrete from J.J. Mottes. The aggregate used in the Mottes cement “recipe” was quarried in west Willington, CT at Becker’s Quarry. The Becker’s Quarry aggregates were used in the Mottes concrete as late as 2014. Within this quarry, there is a vein of a naturally occurring mineral called pyrrhotite – this is our villain. It’s not necessarily visible to the eye and would have been crushed, presumably unknowingly, along with the other stone to create the aggregate used by Mottes. 

Why is only a 30-ish mile radius from the quarry affected? 
According to industry standards, concrete must be poured within 90 minutes of mixing the water with the cement and aggregates. This means that a cement truck has to reach the job site and pour the cement before this 90 minutes is up and this leads to the 30 mile estimate. There are variables that may qualify an old batch to still be used after 90 minutes but this 90 minute rule is a well-established standard. Please note that there have been houses beyond this 30 mile radius with crumbling foundations. If yours looks suspicious, it’s worth pursuing further. However, in towns beyond this distance, a closer concrete company would likely have been used. 

About Pyrrhotite
Pyrrhotite is an iron sulfide mineral that can be found naturally in aggregates. When exposed to water and oxygen, pyrrhotite undergoes a series of chemical reactions that convert it into other compounds and when these compounds are exposed to air and water, they expand and decay. As they expand, they create cracks and holes. Now, it becomes a compounding problem because these cracks and holes, which may be tiny at first, let more and more air and water in allowing more and more decay to occur and it gets worse and worse as this process repeats. It can take more than a decade before homeowners realize the full extent of what is happening. 

thatWe aren’t sure what factors at each property may speed up or slow down the decay process but we have personally observed a couple of things we feel impact the decay process. First, it can be easy to put your head in the sand about this problem if you have a finished basement! Bad news is that finished basements may accelerate the decay process because moisture can become trapped behind sheetrock walls. The plastic that’s sometimes put between the foundation and sheetrock further traps moisture. We’ve worked on houses where the foundation looked fine from the outside but when we demo the walls, the insides of the walls are covered in mold and the interior foundation walls are covered in large webs of cracking. This is what is called “mapping” – the cracks run in all directions and look like a map. Next, we have noticed that there can be stark differences between the condition of walls in one basement. Some walls might be terrible and other walls may look perfect. We have found that if a foundation wall is shielded from water by a porch or is adjacent to a garage or an addition, the decay seems to be delayed or prevented. The less water  touching it may mean slower or prevented decay. 

We also don’t know that every load of concrete from Mottes was properly prepared. We’ve heard stories that suggest two additional issues may have affected some loads of concrete from Mottes. One is that the water to cement ratio in the concrete was not always correct. This would mean that some of the watered down cement that was poured would have been weaker than it should have been to begin with. This extra water may also have accelerated the start of the pyrrhotite’s decay process. This could explain why some houses show a lot of cracking quickly and others don’t. 

Another is that the 90-minute rule may not have always been followed by Mottes. Some “expired” concrete that was left over and brought back to Mottes from the job site may have been mixed in with a fresh batch instead of being disposed of. This could have compromised the new batch and made it weaker. Add in the pyrrhotite variable and this may have further weakened the concrete allowing it to decay faster in some homes. 

If your home was built in one of the towns served by J.J. Motes, it’s important to thoroughly and regularly inspect the concrete walls on all sides, inside and out. Just because your house doesn’t show signs of it today, that doesn’t mean it won’t in five years. The only way to know for sure if your foundation’s level of pyrrhotite is within the range of concern is to obtain a core test. This test will measure the percentage of pyrrhotite in your foundation. There is financial assistance available for core testing through the Capitol Region Council of Governments (CRCOG) and we are an approved core testing provider.

Concrete = Cement + Water + Aggregate

Cement = a combination of lime, silica, alumina, magnesia, sulfur trioxide, alkaline, iron oxide, and calcium sulfate. These “ingredients” are generally extracted from limestone, clay, marl, shale, chalk, sand, bauxite, and iron ore. 

A mix of cement and water makes a mixture that’s called a slurry.

Sand, gravel, and crushed stone, aka aggregates, are added to the mixture.

Through a chemical reaction called hydration, the cement paste hardens and becomes strong. One key to making a strong concrete that will last for a long time depends on how much water goes into the concrete mixture and this amount is determined by a ratio. If there’s too much water, the concrete will be weaker and may cause, for example, more cracking than usual even in a “healthy” foundation. 

What makes concrete stronger or weaker? 
High-quality concrete is produced by lowering the water-cement ratio as much as possible without sacrificing the workability of fresh concrete, allowing it to be properly poured, worked with, and cured.

How do they know if a batch is properly mixed? It’s possible to check this by what’s called a “slump test” which measures the flowability of the mixture. When concrete is poured, it needs enough water to pour out of the cement truck and to properly fill the foundation forms but not so much flowability that it’s too watery and therefore weaker. In Connecticut, slump tests are required for commercial construction but not for residential construction. Here’s a nice video that shows how a slump test is done. 

Back to our story
Now that you understand the “ingredients” in concrete, let’s talk about the source of the aggregate used to produce the concrete from J.J. Mottes. The aggregate used in the Mottes cement “recipe” was quarried in west Willington, CT at Becker’s Quarry. The Becker’s Quarry aggregates were used in the Mottes concrete as late as 2014. Within this quarry, there is a vein of a naturally occurring mineral called pyrrhotite – this is our villain. It’s not necessarily visible to the eye and would have been crushed, presumably unknowingly, along with the other stone to create the aggregate used by Mottes. 

Why is only a 30-ish mile radius from the quarry affected? 
According to industry standards, concrete must be poured within 90 minutes of mixing the water with the cement and aggregates. This means that a cement truck has to reach the job site and pour the cement before this 90 minutes is up and this leads to the 30 mile estimate. There are variables that may qualify an old batch to still be used after 90 minutes but this 90 minute rule is a well-established standard. Please note that there have been houses beyond this 30 mile radius with crumbling foundations. If yours looks suspicious, it’s worth pursuing further. However, in towns beyond this distance, a closer concrete company would likely have been used.

If your home was built in one of the towns served by J.J. Motes, it’s important to thoroughly and regularly inspect the concrete walls on all sides, inside and out. Just because your house doesn’t show signs of it today, that doesn’t mean it won’t in five years. The only way to know for sure if your foundation’s level of pyrrhotite is within the range of concern is to obtain a core test. This test will measure the percentage of pyrrhotite in your foundation. There is financial assistance available for core testing through the Capitol Region Council of Governments (CRCOG) and we are an approved core testing provider.

If your home was built in one of the towns served by J.J. Motes, it’s important to thoroughly and regularly inspect the concrete walls on all sides, inside and out. Just because your house doesn’t show signs of it today, that doesn’t mean it won’t in five years. The only way to know for sure if your foundation’s level of pyrrhotite is within the range of concern is to obtain a core test. This test will measure the percentage of pyrrhotite in your foundation. There is financial assistance available for core testing through the Capitol Region Council of Governments (CRCOG) and we are an approved core testing provider.