Abutment Gutters in Lead: Design & Installation Guide
Where roofs meet vertical walls, abutment gutters in lead channel rainwater safely away. Incorrect detailing leads to leaks and masonry staining. This guide explains codes, falls, bay sizing and fixings in line with Leadwork Standards.
1. Code Selection
Code 5 lead is the most common choice for abutment gutters. For wide or exposed details, Code 6 may be necessary. Heavier codes cope better with water loads and thermal movement.
2. Bay Sizes & Joints
Limit bay length to 1.5 m (Code 5) or 2.0 m (Code 6). Joints must overlap by 150 mm with welted edges. On long abutments, expansion joints should be included.
3. Falls & Drainage
Abutment gutters require a fall of at least 1:80. Outlets must be correctly sized and positioned to prevent standing water. Always plan outlet positions during design, not after installation.
4. Integration with Roof & Wall
Lead should extend sufficiently under the roof covering, with soakers or flashings as required. Masonry chases should be cut to 25 mm depth, with fixings spaced at 450 mm centres.
5. Finishing & Maintenance
Use a suitable pointing mortar or sealant in chases. Apply patination oil to visible leadwork. Inspect gutters regularly for debris buildup.
FAQs
What lead code should I use for abutment gutters?
Code 5 is most common, with Code 6 used for wider or more exposed abutments.
How much fall should abutment gutters have?
At least 1:80. Greater falls are recommended where water flow is heavy or outlet capacity is limited.
Do abutment gutters need expansion joints?
Yes, on long runs or where bay sizes exceed recommended lengths. Joints prevent thermal cracking.
How do abutment gutters connect to the wall?
By chasing lead into the wall at 25 mm depth and pointing with a suitable mortar or sealant.
What maintenance do abutment gutters need?
Regular inspection and clearing of debris, plus checking that outlets are free-flowing.
Next in the series (Post 12): Bay Roofs in Lead — design, bay sizing and jointing for projecting bay windows.
