Slate Roof Condition

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.

Slate roof condition. However as long as the slates are physically intact the roof is serviceable. The white visible in pennsylvania slate is evidence of efflorescence lime deposited on the slate surface. Eflorescence almost fills the upper slates and there are many thin delaminating slates. Examples of slate roofs in poor or worn out condition this poor condition slate roof sports many loose slates.

Some slates have been known to last over 200 years. Tar or roofing cement should not be found at chimneys sidewall flashings plumbing vents or elsewhere. Sample roof condition report slate roofing this is an example of an actual roof condition report. Slate roof repair history helps diagnose the condition of a slate roof tar or roofing mastic is normally an indication of improper maintenance.

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. More than 25 of this roof is bad beyond economical repair. The moisture retained in the slate can also begin to cause the wood roof deck to rot especially if the original felt underlayment is in poor condition. 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.

The addition of slate to a house not framed for this purpose will require an analysis of the roof framing system. The roof survey of multiple slate roofs was performed by professional roof consultants. If the whole slate is white in color and scaling you should consider the slate to be at the end of its life. 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.

It should be considered a temporary unreliable repair.