Slate Roof Condition

Slate roof repair history helps diagnose the condition of a slate roof tar or roofing mastic is normally an indication of improper maintenance.

Slate roof condition.

The white visible in pennsylvania slate is evidence of efflorescence lime deposited on the slate surface. It should be verified whether fastener corrosion is widespread or localized in areas subject to concentrated water flows such as below dormer valleys or below where a low slope roof drains onto the slate roof. The lower the slope of the roof the greater the rate of weathering and deterioration as the slates tend to stay wet for a longer period of time after each precipitation event. Some slates have been known to last over 200 years.

A slate roof can weigh as little as 700 pounds per square up to 8000 pounds where 2 thick slates were used on a graduated slate roof. The addition of slate to a house not framed for this purpose will require an analysis of the roof framing system. It should be considered a temporary unreliable repair. More than 25 of this roof is bad beyond economical repair.

Sample roof condition report slate roofing this is an example of an actual roof condition report. If the condition is typical and widespread it is likely time to replace the roof lest more shingles continue to slide down slope or the shingles become subject to blow off in high winds. However as long as the slates are physically intact the roof is serviceable. Inspecting slate roofs how to inspect slate roofing for condition damage leaks guidance for ashi nahi nabie creia tarei nachi home inspectors and building inspectors engineers architects roofers course notes on slate roofing inspection diagnosis repair a class on how to inspect the condition of slate roofs questions answers about slate roof inspection diagnosis evaluation.

If the whole slate is white in color and scaling you should consider the slate to be at the end of its life. Examples of slate roofs in poor or worn out condition this poor condition slate roof sports many loose slates. Tar or roofing cement should not be found at chimneys sidewall flashings plumbing vents or elsewhere. Eflorescence almost fills the upper slates and there are many thin delaminating slates.

Installed properly slate roofs require relatively little maintenance and will last 60 to 125 years or longer depending on the type of slate employed roof configuration and the geographical location of the property.