Slate roofs can last decades without the need for replacement. Sometimes original slate roofs have been in situ for over 100 years before any real problems begin to occur. Sometimes slate will begin to slip out of position due to nail erosion, allowing rainwater to penetrate into the building. But with a bit of maintenance this can quite easily be fixed.
At some point though, once an original roof has reached this stage and the slate fixings have started to fail, it may turn into an ongoing battle of repair and cost, to keep your roof watertight. We will always endeavor to save you the cost of a reroof and give you an honest appraisal of your roof with pictures, to show you exactly what we are looking at and then let you decide a way forward.