Should I Clean or Replace My Roof?

Kristin Luna
Written by Kristin Luna
Reviewed by Ami Feller
Updated July 13, 2022
beige house gray roof
Photo: karamysh / Adobe Stock

Here’s what to know if you’re thinking of sprucing up your roof

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Nothing ruins the vibe of your home’s exterior aesthetic quite like a dirty or moldy roof, particularly if your paint color and roofing are both on the lighter side. The good news is that roofing materials are designed to last for decades, so cleaning is often the most sensible option if your roof simply is tainted by dirt, mold, or algae. If your roof has run its lifespan, however, it might be time for a new one.

But before you decide which route is best for your home, you need to know the pros and cons of roof cleaning and roof replacement.

Roof Cleaning vs. Roof Replacement

Replacing a roof is a big financial investment that requires a lot of work, whereas cleaning it can save you time and money. But how do you know when it’s time to replace it, or if your room simply needs a good cleaning?

When Should You Clean Your Roof?

worker cleaning roof with high pressure hose
Photo: Marina Lohrbach / Adobe Stock

Routine roof cleaning is important because it not only keeps it beautiful, but it also extends its life. Cleaning your roof includes removing all the dirt and debris that's collected, as well as clearing out your snow guards, removing leaves and sticks from gutters, and also addressing any other areas that are prone to buildup.

Other signs to look for when it’s time to clean your roof include the presence of fungus, algae, or moss that may be building up out of your sightline. Moss can cause your shingles to peel away from the adhesive connecting them to the adjacent shingle and blow off in a storm or strong wind. As the moss causes the roof to degrade, you might experience more serious problems like wood rot and decay down the line.

The common black streaks that form on asphalt shingle roofs are not necessarily a sign of an old roof. Rather, this unsightly surface mold, which hasn’t started to collect moss or algae, can often be fixed with a soft washing. This typically is done with a garden hose and cleaning products that dissolve the spores. The soft-wash process is highly effective and can make a roof look brand new again.

If the discoloration is severe, you’ll need to use a high-pressure water sprayer instead. Just be sure to never use a power washer on an asphalt shingle roof, because it will remove the granules and destroy the roof—instead, opt for a soft wash. A power wash is fine for roofs made of metal, tile, or slate. 

This method requires more direct and close contact between the sprayer and the roof. This also means the additional expense of a contractor with a bucket lift system if your peaks are steep. Less pitched roofs that can be walked on are more easily accessible and therefore should be more affordable. If you don’t feel like tackling the mold yourself, it may be time to hire a professional to pressure-wash your roof.   

When Should You Replace Your Roof?

With regular cleaning, a roof should last between 20 and 50 years for shingle roofs, 50 years or more for metal roofs, and as long as 100 years for concrete or clay tile. If you’re at the end of the lifespan for your roof type, it’s worth replacing it instead of simply doing a thorough clean.

Before you commit to new roofing, it’s important to understand what a roof replacement entails. Typically, the contractor will start by removing every asphalt shingle, The underlayment, and all metal flashings, including gutters and waterproofing metal. This is a heavy-volume job with a lot of material waste and requires either a dumpster rental or multiple truckfuls to haul it all off.

All of the old nails must either be pounded back into the roof or removed and cleaned up with magnetic pickups, often right in the heart of your landscaping. If the removal process unearths damage to the roof, the old wood will need to be cut out and replaced. Once the old roof is removed and the surface is prepared for the new roof, the roofers will install new underlayment. As they install the new roof, they’ll replace the old flashings and pipe jacks with new ones. After the roof is complete, they can install gutters. If the gutters are being replaced, it’s best to remove them before installing the new roof. More often than not, roof shingles are installed with pneumatic tools, which are powered by an air compressor. Installing a new roof can be noisy and messy, but at the end of the job, the mess should be cleaned up and hauled off.

Pros and Cons of Replacing Your Roof

worker installing ceramic tiles on roof
Photo: bilanol / Adobe Stock

Replacing a roof can be costly, but worth it when considering the important role a roof plays in your home’s wellbeing. 

Cost Benefits of Roof Replacement

Adding a new roof instantly increases your home’s value. If you’re selling or planning to refinance your home, and your roof is at the end of its lifespan, it might be worth the extra investment to replace it.

Like any construction job, the price to replace a roof depends on the materials you choose and the labor involved. A new roof can cost anywhere from $5,000 to $45,000, depending on square footage and what kind of home you own. Cost of labor will depend on where you live, but in general you can expect to pay $25,000 on average to replace your roof

An asphalt shingle roof is on the lower end—averaging around $8,000 to $15,000 for a 1,600-square-foot home—though it has a shorter lifespan at 25 to 50 years. With a 20-to-30-year lifespan, a wood shingle roof costs around $21,500 for a 1,600-square-foot house, while clay or asphalt shingles will give you the most longevity (up to 60 years) but also cost the most, at around $21,000 for a 1,600-square-foot home.

The Difficulty of Replacing Your Roof

If you have a technically challenging roofline, it’s going to cost more money to replace it. Roofing is a time-and labor-intensive job that requires a substantial skill set and strength and is on the more challenging end of the DIY spectrum. Unless you have prior experience with roofing, you might want to hire a local roofer to complete the job instead of tackling it yourself.

Time Required to Replace Your Roof

Roofers work in large teams and often complete an entire tear-off and replacement in one day. Complicated landscaping, difficult access points, or technical gables can stretch the project into multiple days, but for a residential home, replacing a roof rarely takes more than a workweek to complete.

Summary of Roofing Options

  • If your roof is more than 20 years old, it might be time to replace it.

  • If your roof is coated in dirt, mold, or algae, you can likely get away with a deep cleaning.

  • Replacing your roof can increase the resale value of your home.

  • On average, it costs $25,000 to replace a roof.

  • Replacing a roof is a highly challenging DIY job, so it’s better to call a pro.

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