When a roof decking gets exposed to wet conditions or moisture, it can develop rot that compromises your roof’s structural integrity. The tricky thing about this issue is that it can easily go unnoticed -and for a long time, too- because roof decking is hidden under the roofing shingles and above the attic insulation.
Finding out that your roof’s structure requires repairs is never good news, but it’s even more of a hassle with decking. Unless the problem is so severe that you can see visible signs of it, you’d need an inspector or roofer to get up there and look around, possibly tearing off the shingles.
If it turns out you need to do some repairs or have them done, the main concern becomes: how much does it cost to replace roof decking?
The total price of such a job will vary according to several factors such as the used material, the size of your house, and your area’s local labor costs. Assuming you’ll use roofing plywood, a single sheet measures 4 x 8 feet and covers an area of about 32 square feet.
As such, on an average home of size 2,400 square feet, replacing roof decking will take approximately 75 sheets of plywood to replace the roof decking, costing you around $1,000 to $1,600 for the material alone, considering that the average price of sheathing plywood is about $14 to $21 per sheet.
Don’t forget to factor in roofing labor costs, which fall between $1.00 up to $3.00 per square foot on average.
When it comes to roofing repairs and replacements, it’s wise to expect the best but prepare for the worst, especially budget-wise. In today’s article, we’re discussing all the aspects of the cost to replace roof decking to help you form a better idea of the situation, whether you need to do it soon or suspect it’ll happen in the future.
What is Roof Decking?
Roof sheathing or roof decking is the foundation of your whole roof. It involves installing a layer of plywood, OSB, or another roofing material between the joists and trusses and the insulation/weather-proofing layer of the roof.
The purpose of sheathing is to provide support for the roof’s structural work as it prevents the direct attachment of shingles to joists and trusses by evenly distributing their weight shingles. It also offers the house extra protection by incorporating an additional layer of insulation to resist leaks and reduce the spread of fires.
Roof sheathing must be tough enough to endure the shingles’ weight and sufficiently durable to allow for a little give. Despite being invisible from the outside, choosing a proper roof decking material is critical to avoid major structural problems.
Roof Decking Types
The most commonly used roof decking materials for residential purposes are plywood or OSB (oriented strand board), a plywood composite. Compared to plywood, OSB is less expensive. However, it’s also less dense and is more prone to moisture-related issues.
Beyond these two, there are other materials you can use for roof sheathing. Here’s a simple breakdown of roof decking types:
- OSB (Oriented Strand Board) — OSB is quickly taking the lead as the go-to material for roof decking thanks to being durable, readily available, and more affordable than almost all other alternatives.OSB consists of wood fragments bonded together using a specialized adhesive. Coupling this type of wood sheathing with modern engineering technologies results in a decking material that’s tough, sturdy, and uniform.
- Plywood — a long-time popular choice, 1/2-inch structure plywood is installed the same way as OSB with the standard spacing required to accommodate thermal contraction and expansion.Thanks to the high density of plywood, it better prevents moisture from penetrating the wood and rotting or damaging your roof. Plywood is tough and durable like OSB, but it has superior resistance to moisture accumulation and rot compared to OSB.
- Plank — the popularity of plank has drastically declined since the 1970s, but it’s still used nowadays for specific roof types such as wood shakes. Instead of laying down a flat-level plane during installation, wood planks are placed with about 1 1/2 inch spacing to promote airflow.
- Tongue and groove — this roof decking type uses boards sized 2 x 6, where one end of each board is a “tongue,” and the other is a “groove.” This allows boards to lock into one other when installed. Tongue and groove roof decking is often added to roofs that don’t have a ceiling. As a plus, the boards create an aesthetically pleasing, unique look that you can enjoy from the inside.
- Concrete — ideal for structures where the roof requires significant strength and support, concrete is becoming more and more popular thanks to its eco-friendly advantages and excellent fireproofing performance. Usually, this type of roof decking is poured into multiple forms or installed as precast boards. Then, we use bars to reinforce it.
The pros of concrete sheathing include being easy to clean, low maintenance, and more likely to protect your roof against wind damage.
Why Does Roof Decking Rot?
The most common problem that homeowners come across with their roof decking is rot. So what causes your wood roof sheathing to go soft and rot? Well, moisture is the main culprit.
Since most roof decking is constructed out of plywood or plywood composites, it’s highly prone to sustaining damage or rot from water upon exposure to excess moisture for a prolonged time. This can happen through several ways such as:
- Old or worn-out shingles
- The flashing surrounding the chimney gets torn
- Insufficient roof ventilation
- Overflowing gutters
- Accumulation of ice or snow during winter months
- Too much heat or excess humidity in your attic
This brings about an important question, how do you know when your roof has rotted? Some signs indicate the rotting of roof decking, which include:
- Roof leaks
- Wet spots on the ceiling
- Stains on your interior walls
- Water stains on the rafters
- Cracked paint and peeling wallpaper
- Sagging of the roofline or ceiling
- Development of mold and mildew in your attic
Should You Repair or Replace Your Roof Decking?
If your roof decking is indeed suffering from rot and you’re hoping to fix the issue with a quick patch job, you need to reconsider.
You see, when it comes to wood rot, repairing your roof decking is just not going to rid of the problem. Instead, it would help if you replaced it entirely and as soon as you could.
The longer you leave the roof decking rotten or damaged without replacement, the more issues will arise, leading to more expensive repairs.
How Much Does it Cost to Replace Roof Decking?
The total expense of such a project will vary according to several factors, including the type and quantity of the used material, the size of your house, and your area’s local labor fees. Assuming you’ll use roofing plywood, here’s what you need to know:
A single sheet measures 4 x 8 feet and covers an area of about 32 square feet. As such, on an average home of size 2,400 square feet, replacing roof decking will take approximately 75 sheets of plywood to replace the roof decking.
This will cost you around $1,000 to $1,600 for the materials alone, considering that the average price of sheathing plywood ranges between $14 to $21 per sheet. Additionally, you need to factor in roofing labor costs, which fall between $1.00 up to $3.00 per square foot on average.
Similarly, if you’re replacing the plywood sheathing on a smaller house of an area, say, 1,000 square feet, you’ll need about 34 sheets only for $600 on average. To make things simpler, check out the following step-by-step guide on how to calculate the cost of replacing roof decking using any sheathing material:
Step 1 – measure the length of the decking sheet that you choose to use.
Step 2 – measure the width of the decking sheet that you choose to use.
Step 3 – multiply the length and width of the decking sheet. The number you’ll get is the material’s total square footage. For example, the total square footage of a plywood sheet sized 4 x 8 feet is 32 square feet.
Step 4 – Divide the area of your roof (in square feet) by the decking sheet’s total square footage. This resulting number is how many sheets are required to cover the entire roof.
Step 5 – multiply the required number of decking sheets by the price of a single sheet to calculate the total cost of the decking material.
Now that you’ve figured out the total cost of your roof decking material, it’s time to understand how the cost of roofing labor works. With a couple of varying factors, such as where you live and what company you’re dealing with, the average labor fees per square foot range between $1.00 and $3.00.
On the other hand, some roofers charge per square (an area of 10×10 feet), so their labor fees will average between $100 and $300 for every square.
How Much Does Roof Inspection Cost?
A roof inspection is important to help in:
- Identifying potential problems
- Providing solutions for fixing whatever issues found
- Determining the current condition and expected lifespan of your roof
- Giving you pointers on how to maintain the excellent condition of your roof
- Finding out if your roof decking is rotted, damaged, and needs to undergo a replacement job.
On average, the cost of a roof inspection ranges from $100 up to $600. In most cases, homeowners are charged around $300 to $400 for an external and internal inspection of a sloped roof sized about 1,500 square feet.
The price you’ll end up paying for a roof inspection depends on the roof’s material, pitch, size, and condition.
How Often Should You Schedule Roof Inspections?
Periodic roofing inspections help you get ahead of structural issues before they become too serious or expensive. So how often should you have an inspection done?
As the roof is constantly exposed to various weather conditions and stressors, the general recommendation in the industry is to schedule a professional inspection two times a year: once in the spring after the ice and snow has passed on, and again in the fall, after the hot temperatures have gone down.
Also, make sure to get a roof inspection after any weather phenomenon that’s possibly damaging, such as a hurricane or a massive storm.
Wrap Up
There you have it, a complete guide on how much it can cost to replace roof decking. As you can tell by now, many factors affect the final expense of the project, such as the size of the roof, the materials used, and the labor charges.