The average roof is expected to last for about 20 years, but will be dependent on the material it is made out of, the amount of slope and the weathering over time. 

Asphalt shingles are the most popular kind of roofing shingles and are made as either fiberglass-based or organic-based.

Fiberglass-based: Made up completely of glass fibers surfaced by an asphalt coating, then a mineral granule that is weather-resistant. 

Organic-based: Made up of a variety of cellulose fibers that is surfaced by a coating of asphalt then a mineral granule that is weather-resistant. 

When a roof is shingled over, it does not last for as long and when it does need to be replaced again, both layers will need to be removed. 

If your roof itself is in good condition and there are no rotting wood holes, then it could be an option to shingle over the old roof. This process is faster and less expensive initially, due to the fact that it does not strip the old shingles first, therefore requiring less labor. 

If you decide to have your roof torn off completely, then we can inspect it to see if there is any damage or rotting in any places. This makes it much easier to pinpoint and resolve any issues you might be having with your current roof. If you are having issues with your roof leaking, tearing it off will be the better decision to make. Although it may be more expensive now, it will end up saving you more down the road.