If you are embarking on a new build, it is prudent to have soil testing done on your land before the foundation is laid out. Although typically most areas are viable for construction, you need to know beforehand if you are dealing with reactive or non-reactive soil. Soil reactivity may sound like a scary term, but it is actually a common condition that occurs in various grades. The lower your soil reactivity, the better the conditions for your new construction.
What does soil reactivity refer to?
Soil reactivity refers to how the soil on your site will react depending on its moisture content. The extent to which it fluctuates will play a significant role in how stable your building will be. Generally, all soil will expand or contract in accordance to the amount of moisture it has. Getting a soil test done will establish the extent at which your individual soil will shift with the changing moisture content.
How does soil reactivity affect construction?
There are a couple of ways that highly reactive soil can affect your new structure. However, if the soil reactivity is not too high, the construction contractors can bypass the fluctuating changes using concrete slabs best suited for those particular reactivity levels.
In the event that reactive soil becomes waterlogged due to either natural causes or a burst underground pipe, its reactivity will begin to rise. This in turn will apply pressure on the concrete slabs that have been used to create the foundation. If the foundation is not strong enough, not only will the foundation suffer extensive damage, but also the structure itself.
On the other hand, if reactive soil becomes too dry, it presents its own set of problems. The less moisture content in the reactive soil, the more the soil contracts. This causes it to take in the ground that is supporting the foundation. If the extent of the soil contracting is significant, it poses the risk of the concrete slabs in the foundation buckling or even completely slipping out of place. This is a tremendous risk for all types of structures, but more so smaller buildings that do not have a wide foundation base.
How is soil reactivity graded?
The good news is that having reactive soil does not necessarily mean that no construction can occur on the site. After soil testing the grades range from A (which is the most stable type of reactive soil) to P (which is the most problematic as it is susceptible to mudslides). Having your soil tested beforehand will let you know your soil's reactivity so your construction contractors can advise you on the best way forward.