When is the Right Time to Replace Your Roof Underlayment?

The roofing subfloor is an essential part of your roofing system, acting as a water barrier and helping to insulate and protect your roof for many years. Over time, however, the bottom layer will start to wear out and need to be replaced. But how do you know when it's time to replace your subfloor? It's not always visible to the naked eye, and Florida's climate can affect its longevity. Here are some guidelines to help you evaluate if it's time to replace the bottom layer of your roof. A subfloor is the structural coating that encompasses the joists of the floor.

It is usually completely hidden under some kind of finished flooring material. Depending on when the house was built, the subfloor could be made of soft wood boards such as pine or spruce, plywood or OSB (oriented fiberboard). OSB is a composite of glue and scrap wood strips, in sheets that are 4 feet wide and 8 or 12 feet long. OSB is quickly installed and is less expensive than real wood or plywood, making it the go-to material for modern subfloors. Under normal conditions, a subfloor can last as long as the house itself - up to 25 years or more with regular inspections.

It is important to schedule periodic inspections of the subfloor every 3 to 5 years, or after you suspect that it is damaged, to maximize its useful life. However, if a subfloor is damaged or defective, it can only last 20 to 30 years. If this is the case, you may have to remove the layers from the floor and get to work. Here are five signs that it's time to replace a subfloor:

  • The floor feels soft
  • There are visible signs of water damage
  • The floor has been exposed to pests
  • The floor has been exposed to debris or tree branches
  • Your roofer requires a new layer of subfloor during roof replacement
If you suspect any of these issues with your subfloor, it's best to hire a roofing specialist to replace it. Most shingle manufacturers require a new layer of subfloor during roof replacement in order for your tile's warranty to take effect.

Insisting on keeping the old undercoat may void the warranty. If you use a quality subfloor and keep your roof clean of pests, debris and tree branches, it's very possible that your roof will last 40 years or more before it needs to be replaced again. To help you understand why replacing your old roof underlayment is important, residential roofing contractor TopTier Roofing discusses four reasons why you should replace it.