Flashing Laps

Laps in flashings should comply with the following criteria:

• Water must flow over a lap, not into it,
• a lap must not rely solely on sealant,
• sealed laps must be mechanically fixed at 50 mm centres,
• unsealed laps must have a minimum cover of 150 mm, and 
• a minimum of 100 mm cover is recommended for sealed laps to facilitate the correct alignment of two flashings.