How to Repair Water-Damaged Siding Before a Larger Project Arises

Unsightly water damage gone in a day

Exterior of a blue suburban home
Photo: Joe Hendrickson / iStock / Getty Images Plus / Getty Images
Exterior of a blue suburban home
Photo: Joe Hendrickson / iStock / Getty Images Plus / Getty Images
SKILL LEVEL
Intermediate
COMPLETION TIME
1 hour
COST
$25–$50
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What you'll need:
TOOLS
  • Caulking gun
  • Ladder
SUPPLIES
  • Sealant
  • Disposable gloves

Water damage is a challenge no homeowner wants to face. But when that damage is located on your home’s siding, it's something you should handle sooner rather than later. Water-damaged siding can lead to rot, mold, and other structural problems that escalate over time. If you're noticing signs of mold or siding pulling away from your home, learn how to repair water-damaged siding to prevent a bigger project down the road.

Preparing to Repair Water Damaged Siding

Repairing water-damaged siding doesn't require many supplies or tools, so it's a perfect project to take care of in one day. To prevent further damage, you'll be sealing up the leak and assessing the damage to the siding in case you need to factor a professional siding replacement cost into your budget.

Depending on the location of the leak, a ladder may be required to reach it. If you don't have someone to spot you, don't feel comfortable working on a ladder, or are unsure of how to caulk siding, it's a good idea to hire a siding repair professional to tackle this one.

  1. Identify the Location of the Leak

    Repairman climbing the ladder
    Photo: Warchi / iStock / Getty Images Plus / Getty Images

    Your first course of action is to identify the location of the leak. On the outside of siding, you may notice signs of mildew, which could be either green, brown, or gray. Rotted wood siding will appear wet, dark, or even black. This is especially cause for concern if it hasn't rained or you aren't able to easily identify why the siding appears wet.

    You will likely notice a hole with any of these types of damage. Once located, you'll need to pull away any water-damaged siding to find the source. Inspect adjacent areas as well, as the leak could be causing more damage than you realize. Here’s how to remove vinyl siding if you’re new to this step.

  2. Plug Holes and Cracks With Caulk

    Damaged metal frame of window on house
    Photo: Justin / Adobe Stock

    Once you've located the holes or small cracks in your siding, you're ready to plug the source. Using a caulking gun, fill the hole or cracks with sealant. While wearing disposable gloves, smooth the caulk line using your finger to ensure a clean seal. If any holes or cracks appear on the siding close to the water damage, you'll want to seal those off as well. 

    If there is mold or mildew present, you need to remove mold from siding before caulking. Use an all-purpose vinyl cleaner and some elbow grease to scrub it away. Pat it dry with a towel before caulking.

  3. Repair Damaged Siding

    Man painting exterior of house
    Photo: Image by Marie LaFauci / Moment / Getty Images

    Depending on the type of siding, repairing it will vary from the process to the siding repair cost. In most cases, you can paint over the caulked area, but you will need to let the caulk sit for at least 24 hours before doing so. You can also reaffix a new piece of siding in that area, but depending on what you're able to find, you may not locate a color that matches exactly.

  4. Take Preventative Measures

    Man cleaning the vinyl
    Photo: Willowpix / E+ / Getty Images

    To prevent further water damage, reduce the amount of water that could penetrate your siding. Ensure your gutters and downspouts are free of clogs and repair them as needed. If flashing around doors and windows is damaged, replace it. 

    After heavy rainfalls, check the exterior of your home to see if any pooling or excess water is present near the siding to assess the damage. At least twice a year, do an inspection of your home's exterior to keep up with siding maintenance.

    If you're looking to install new siding, take special care of replacing new siding over the old siding and consider opting for low-maintenance siding to reduce your future repairs. For instance, cleaning vinyl siding is a manageable project for most homeowners, and even aluminum siding repair is within some DIYers’ wheelhouse.

DIY vs. Hiring a Pro

Knowing how to repair water-damaged siding is a simple enough task for a handy DIY homeowner to tackle. Plus, you're looking at a project that only costs $25 to $50. However, due to the damage likely being caused to your home's foundation and structure, it's smart to hire a local siding repair professional. A pro can assess if any structural damage has taken place and recommend solutions for fixing them, which is often outside the wheelhouse of DIYers. The cost of repair with the help of a siding pro will depend on the level of damage you're dealing with, but you can expect to pay a siding repair professional between $40 to $90 per hour for their work, plus any materials required.

Frequently Asked Questions

When moisture infiltrates your siding, it can result in deterioration and decay of the sheathing, cause structural damage to your foundation, and provides an ideal breeding ground for mold. Mold growth can lead to various health-related problems, such as itchy eyes, sneezing, allergies, and asthma. Mold and dampness commonly attract a wide range of insects, so if your siding has taken any kind of water damage, it could invite some unwelcome guests.

Yes, it is common for mold to grow on the underside of the siding due to the moist atmosphere. When there is an abundance of moisture, mold has the ideal environment to spread and thrive. This fungus can be found on virtually any surface, both indoors and outdoors. Generally, it is most active when the environment is warm, damp, and humid.

To fix rotted wood under siding, you'll need to remove the damaged areas of the wood and then repair the rotted board. To fix the rotten wood, you'll need a wood hardener and a filler. Coat the rotted areas with the hardener, and then blend it with the filler. Use a putty knife to spread the concoction into the areas needing repair. Check out our guide to wood siding repair for more details.

While homeowners' insurance can include coverage for siding, general wear and tear of siding is not covered. If your siding is rotting—especially because you haven’t kept up with proper siding maintenance—replacement siding will likely not be covered by your homeowners' insurance policy. Instead, insurance generally covers siding repair or replacement if your siding has been damaged by extreme weather, vandalism, fire, or some kind of collision, like by a vehicle.

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