Proper shelf angle detailing is critical to supporting masonry veneer while preserving drainage, insulation, and air barrier continuity. This article provides design strategies, product suggestions, and common detailing errors to avoid.
Purpose of Shelf Angles
Shelf angles (also known as relieving angles) support masonry veneer at floor lines, transfer structural loads to the frame, and allow vertical expansion joints. Placement and spacing are governed by veneer weight, wall height, and backup wall capacity. Shelf angles must be flashed, vented, and thermally broken where applicable.
Thermal Break and Drainage Design
- Install continuous insulation behind and beneath shelf angle brackets
- Use thermal isolation pads (e.g., stainless steel stand-offs or composite spacers)
- Ensure weeps and through-wall flashing exist immediately above the angle
- Ventilate the cavity with insect-screened vents or mesh strips
Waterproofing and WRB Integration
Use membrane flashing that extends under the shelf angle and behind insulation to direct moisture out of the cavity. Seal fastener penetrations through WRB with compatible tapes or liquid-applied sealants. Maintain a positive slope on horizontal leg of the angle to shed water outward
Installation and QA/QC
Ensure all flashing is lapped and sealed to direct water to the exterior. Avoid reverse lapping or membrane pinholes at anchor points. Use compatible fasteners with stainless hardware for long-term durability. Inspect angle alignment and embedment prior to brick installation. Shelf angles should not compress insulation or disrupt air barrier planes.
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