A concrete upstand is a concrete element that sits on top of the foundation and forms the transition between the foundation and the first course of masonry. It raises the wall start above ground level, protecting the brickwork or blockwork from moisture and providing a level base to build from.
Upstands are typically between 300 mm and 600 mm tall, though the exact height depends on the required floor level and the depth of the foundation. They can be cast in situ using simple formwork or assembled from precast concrete blocks. In either case, the upstand is reinforced with steel bars that tie into the foundation below.
Application
Concrete upstands are most commonly used in buildings with a crawl space. The upstand creates the perimeter wall of the crawl space, keeping the timber or concrete floor structure elevated above the ground. This gap allows ventilation underneath the building, which helps prevent moisture problems and timber decay.
For DIY builders constructing a garden room, workshop, or small extension, understanding the upstand is important because it determines the floor height relative to the surrounding ground. The upstand must be waterproofed on the outside, usually with a bituminous coating or membrane, and a damp-proof course (DPC) is placed on top before the masonry begins.
When building with a crawl space, the upstand also needs ventilation openings — small grilles or air bricks set into the concrete — to ensure air circulates beneath the floor. Building regulations typically require a minimum crawl space height and a certain amount of ventilation area.
The top of the upstand must be perfectly level, as it sets the reference line for all masonry above. Any deviation here will carry through the entire wall, so careful checking with a spirit level or laser is essential.
Related terms
- Foundation
- Crawl space
- Masonry
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