It pays to have a skilled contractor in your corner when you’re on the market for a replacement stale roof for your home. In an SFGate.com article, writer Stephanie Mitchell says:
Slate’s reputation for durability is accurate to a point, but even the highest-quality slate fails eventually and must be replaced. A roofing expert can tell you how long each type of slate will last, but if you don’t know what type is featured on your new home or when it was installed, simply calculating its age isn’t an option. Nor can you conclude that a handful of failing tiles is cause for replacing the entire roof. Still, you can determine whether to repair or replace your roof by examining it, if you know what to look for.
Slate roof tiles often give the house an aged look, especially for structures that have stood the test of time. The Bay Area has its fair share of houses and other general structures with slate roofing adorning them. If your house has a slate roof that may have seen better days and needs a new cover, trust the work to a roofing contractor from Sunnyvale such as Shelton Roofing.
Your preferred roofer should have free rein to analyze the entire roofing system for various issues to be dealt with, starting with the tiles themselves. Mitchell says that the attic and rafters should be studied for moisture and potential rot, as this is an indicator that the slate tiles above them are already too degraded to be of any use in the new slate roof. The degree of leakages will also have to be checked.
From the Outside
You and your Sunnyvale roof repair contractor can view the roof from a safe distance through binoculars to check if any of the tiles are off-position. Some roofing experts do not recommend stepping on the surface itself as the tiles could crack under your weight.
Take note that some displaced tiles may still be serviceable; a fallen tile that’s still in good shape, for example, may have loose metal fasteners as its problem. Mitchell recommends consulting your contractor about a full replacement if at least 10% of all tiles are not in good condition or many affected tiles could not be replaced without damaging the adjacent tiles still intact.
Certain slate roof varieties are capable of staying up for several decades but some tiles may require replacement to keep the covers up. A roofer like Shelton will help you on that matter.
(Source: How to Tell When to Replace a Slate Roof, SFGate.com)