We often marvel at the buildings that tower above us, their architectural prowess displayed pristinely against the sky. However, equally important but less discussed is the space that lies beneath these structures—the invisible support keeping them firm and unwavering. This segment of a building is often referred to in the construction industry as “Below Grade.” Let’s delve deeper into this construction term, understanding what it encapsulates and its importance in the schematic layout of a building.
Broadly speaking, 'Below Grade' pertains to the portion of a structure located below ground level. It serves as a foundation, a keel to the ship, a root to the tree. The foundation of a building is the core element that supports the entire structure and is designed to transmit loads directly to the ground. The performance of a building during its lifetime largely depends on the quality and design of this underpinning base.
Generally, the section of a building that is below grade includes a basement or crawl space. However, the type of foundation that a building will have primarily depends on factors such as the nature of the building (residential, commercial, industrial, etc.), the soil type, the climate in the area, the water table level, and the budget at hand.
A basement is a space below grade that is typically at least six feet in height. Due to its generous headroom, it's often considered as usable square footage and is fitted out similar to above-grade levels with HVAC, plumbing, electrical, and finished surfaces. A well-constructed basement offers several advantages. Not only does it provide additional living or storage space, but it can also accommodate certain parts of a building’s essential systems like heating, ventilation, and electrical system elements. Consequently, the basement often serves as a finished living area, a workspace, or a utility room.
On the other hand, a crawl space is a below-grade area designed to allow access to the underside of the first floor of a building for repair and maintenance purposes. Unlike a basement, a crawl space is not meant for living or storage but rather as a void between the ground and the bottom of the building, permitting air circulation. This helps keep the building off damp or unstable ground and provides easy access to the under-floor utilities, including plumbing, electrical, insulation, and HVAC systems.
An essential aspect to consider for any below-grade construction is waterproofing. Having part of a building below ground level can lead to high moisture levels, affecting the strength and durability of the building and causing possible damage. Ignoring waterproofing can risk structural damages, unhealthy living conditions, and high repair costs. Hence, even the best-designed foundations include a system to manage water.
In conclusion, the term below grade extends far beyond a simple definition. From basements providing additional living or storage space to crawl spaces ensuring circulation and easy access for repair and maintenance, the below-grade foundation plays a pivotal role in the overall building structure. Ensuring the optimal design, construction, and waterproofing of this below-ground space contributes significantly to the building’s durability, strength, and functionality over time. Unseen and often overlooked - the 'below grade' is the unseen hero in every edifice, standing tall and housing our dreams.