roofing contractor


How do you know when it’s time for a new roof? The only way to be sure of your residential roof’s current condition is to have a licensed professional personally inspect it. Werner Roofing is proud to offer free roof inspections for every client, so you can be sure of your roof’s condition. Every Werner Roofing inspection comes complete with our promise: “We won’t recommend or sell a roof replacement unless it’s necessary.” 

If you’re new to homeownership, or if you’re just having roof trouble for the first time, it may come as a surprise to know about all of the different components of a roofing system. Many homeowners don’t realize that their roof is made up of much more than just shingles and gutters. One very important component of every roofing system is roof sheathing, so we thought we’d take a minute to explain what roof sheathing is, and what it does:

What is Roof Sheathing? 

Roof sheathing, also known as roof decking, is a strong layer of wood boards that are fixed to your roof’s joists and trusses. Your roofer will attach your shingles to these squares or planks of wood.

What’s Roof Sheathing Made Of?

Roof sheathing is usually made of either oriented strand board (OSB) or plywood. Both materials are made of wood, but OSB is more lightweight and costs slightly less. Plywood is very durable but tends to cost a bit more and is heavier. The majority of roofers these days prefer OSB, unless they’re working with a heavier material like slate or concrete roofing tiles. In these cases, plywood is usually a better option.

What Does Roof Sheathing Do?

The primary function of roof sheathing is to strengthen your roof. It offers a sturdy support system to build the rest of your roof system on. That said, it has a few additional benefits:

Helps Stop Leaks

A long time ago, when people were first building asphalt shingle roofs, roof sheathing wasn’t always used. What most homeowners found was that without sheathing, their roofs were much more likely to leak. While today’s asphalt shingles feature a number of weatherproofing treatments, the additional layer of boards gives your roof another layer of protection against the elements. Since many sheathing boards are also weatherproofed, this helps prolong the lifespan of your roof and keeps your home safe from water damage.

Adds Strength and Support to Your Roof

Roof sheathing helps distribute weight evenly across your roof. Since sheathing boards are affixed to your roof’s trusses and joints — its strongest supporting beams — they help ensure that heavy loads of snow and precipitation don’t cause bowing or sagging. They also help your roof to hold up asphalt shingles. Shingles can be a little heavier than you’d expect, and sheathing helps ensure that any weight they add is distributed evenly across the span of your roof.

Fire Protection

Finally, roof sheathing or decking can also help prevent fires. While nothing is 100% fireproof, many roof sheathing materials come with a fire retardant treatment that can help resist fires on the roof or in the attic.

How Can You Tell When You Need New Roof Sheathing?

Roof sheathing is an important component of your overall roofing system. If yours is old, outdated, or damaged, you’ll want to have it replaced as soon as possible. The most common reason to replace roof sheathing is when you re-roof your home, but there are a few other signs to watch out for that will tell you it’s time to replace your sheathing.

It’s Broken

If you can distinctly see broken sheathing boards, it’s time for a replacement. This can happen if a lot of weight is concentrated in one area — like if a tree branch or limb falls on the roof. It can also happen over time if your roof is well past its prime. It’s not hard to spot broken sheathing, as your roof will probably sag, and you may even see sawdust and broken parts in your attic.

There’s Water Damage

Water damage is bad for any part of your roof. If you’re seeing leaks, puddles, or water stains in your ceiling, it’s time for a replacement somewhere. Sheathing water damage is particularly bad because it can affect the structure of your roof. It’s best to get those damaged boards replaced as soon as possible.

You See Rot

If you can see rotting parts of your roof’s sheathing, it’s definitely time for a replacement. Rotting sheathing is most often caused by water damage, but it can be less obvious if you haven’t yet seen leaks.

The best way to check for rotting sheathing is to head up to your attic with a flashlight. If sheathing has started to rot in places, you should be able to see darkened spots in the wood. If your attic isn’t too tall, you can also go around gently with a hammer or even just your hand, and feel for soft spots in the wood.

Light Passing Through Holes in the Roof

As a general rule, it’s not a good sign to see the sky through your roof. If you head up to your attic with a flashlight and can see light passing through holes in your roof, then it’s time to call a roofer. If light is getting through, water will be able to get through too.

Sagging Ceiling or Roofline

The most obvious way to identify roof sheathing damage is through sagging in your ceiling or roofline. If you’re inside and see areas of the ceiling that seem a little closer to you than others, your sheathing might be to blame. Similarly, if you can tell from the outside that there are parts of your roof that are sagging, it’s time to call a professional.

Roof Sheathing and Asphalt Roofing in Holland, MI 


Your roof sheathing is an important component of your roofing system. Sheathing holds up your shingles, keeps the elements out, and helps distribute weight evenly across your roof. If you suspect your Holland or West Michigan home has damaged or old sheathing, get in touch with the experts at Werner Roofing.

We’ve been building Holland roofs for years and would be happy to come out and inspect your roof sheathing to let you know what’s going on. Schedule your free roofing estimate online today, or give us a call at 616-844-5382 and we’ll get you a no-obligation estimate based on a professional inspection.


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