ledge is a reinforced concrete bearing which supports the weight (100Kg per square meter or more) of finished materials such as brick, stone or other veneers acting directly on a footing or other foundation element. Generally, the brick or stone veneer is placed on the exterior of a house or building.
The brick ledge is commonly placed monolithically with the foundation elements, but if the conditions necessitate, it can also be constructed separately. Geometry and reinforcement of brick ledge designed according to the provisions of ACI 318-14 section 11.9 (Special Provisions for Brackets and Corbels).
Construction of Concrete Brick Ledge
ledge is usually constructed integrally with the foundation of the house or building. In this case, the formwork is fixed along with that of the foundation element. After that, the designated reinforcement is installed, and finally, the concrete is poured integrally with the foundation of the structure.
If the bridge ledge is constructed separately, then the construction procedure includes:
- Excavating trench beside the foundation or concrete slab. Common trench depth of 15.24cm and width of 30.48cm is used.
- Place grade at the bottom of the trench and level it properly.
- Fix the formwork and brace the sides with stakes driven in the ground every 1.22m along the outside of the formwork.
- Install reinforcement as per the design values.
- Pour concrete into the brick ledge formwork.
- Compact the poured concrete by tapping the side of the formwork with a hammer. This would eliminate any air pockets and settle the gravel.
- Remove excess concrete
- Smooth the concrete with a concrete trowel.
- Cure concrete till it gains enough strength.
Sometimes flared brick ledge section is constructed, and it shall be reinforced with a line of horizontal rebar, and stirrups.
Design of Brick Ledge
The reinforcement ratio and dimensions of brick ledge can be designed according to the provisions of ACI 318-14 section 11.9: Special Provisions for Brackets and Corbels.
Brick Ledge Flashing
Flashing is commonly used to prevent rainwater penetration into the building which otherwise could have a detrimental effect on the building. If proper flashing is not installed, then it is highly likely that the building would need costly repairs in the future. The placement of flashing for brick ledge is shown in Fig.3.