Lead Code Specification for Guildford Properties
Lead is manufactured in code grades from 3 to 8, with each code representing a different thickness. Using the wrong code is one of the most common lead work failures we encounter on Guildford properties — typically under-specified lead that has cracked through thermal fatigue. Valley linings require code 5 or 6. Chimney back gutters and saddle flashings require code 5. Step and cover flashings require code 4 minimum. Soakers — the individual pieces that step up the slate or tile course beside a chimney — require code 3. We always specify the correct code for each application.
Common Lead Failures on Guildford's Housing Stock
The most frequent lead failures we see across Guildford are: lead valley cracking or splitting from long-run thermal movement where expansion joints were not incorporated; chimney soaker failure where original lead is now 70–80 years old; lead apron failure at the base of chimney stacks where incorrect code was used; and lead flashing pulling out of the mortar joint in the masonry where the turn-in has corroded and lost its grip. Conservation area and listed building properties sometimes have original lead that cannot be directly replaced without specialist matching, which we carry experience of.
Valley Replacement in Guildford
Lead valley replacement is the most common lead work repair we carry out in Guildford. A valley failure typically manifests as a persistent ceiling stain in a first-floor room that does not respond to tile repairs above. We strip the full valley run, inspect and treat the deck boards, and install new lead to the correct code with expansion steps incorporated at the correct intervals. A correctly installed lead valley in code 5 should not require attention for 50–70 years.