My Siding Is Rotting At The Bottom – Why? What To Do?

Wall siding offers protection to a home and enhances its appearance. However, certain areas of the siding such as the bottom are more prone to damage. Over time, this area can rot. Why does this happen and what can you do about it? We have done thorough research and found the answers. 

The bottom section of wall siding can rot because water gathers there and cannot move freely. Rotten wall siding has to be repaired once it is detected.

The repair work can be a DIY project if the damage is on the surface, but major damage under the wall siding requires professional work.

Read on to get insights on the causes of rotting and how to repair your siding. We will also give you tips on protecting wall siding from damage. 

What Causes Siding To Rot?

Close up view at a very rotten white wooden boards that need immediate renovation

Wood is the siding material most prone to moisture damage. When moisture is trapped, this can cause the wood to rot. Rotting issues can often be seen at the bottom of wood siding. Here are some of the reasons that this happens: 

Landscape Plants

Many homeowners plant trees and shrubs near their homes, where they're left to grow tall and cover the walls.

These plants can trap moisture if they are near or on wall siding, especially at the bottom. The area won't dry because it isn't exposed to air. As a result, the bottom of the siding stays wet and begins to rot. 

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Water Leaks

The presence of a water leak behind wall siding can lead to rot. If not addressed right away, it can further damage the siding with mold. 

Mold growth happens when moisture is trapped between the siding boards. Its spores thrive on damp surfaces and form colonies. This will weaken the siding structure. 

The water leak also affects the integrity of the wall foundation. The siding and the wall it is attached to can weaken if the leak problem is not fixed. 

Dirty Gutters

Gutters allow rainwater to flow through drainage pipes and away from a house. However, gutters can accumulate dirt and debris that cause serious damage. 

A clogged gutter causes water to spill out and flow to the roof or walls. Water seeping through the walls of a house can cause the siding to rot. It can also pool on the ground and keep the siding wet, which leads to rotting 

How To Repair Rotten Wood Siding?

Materials needed to repair rotten wood siding, My Siding Is Rotting At The Bottom - Why? What To Do?

Often, rotting wood can go undetected for a long time. It will only show signs of damage when discoloration on the wall is visible. 

Poke the discolored wall with a pen. Wet or rotten siding is soft and will give way once you poke it. If you're handy with tools, you may be able to fix the damaged siding yourself. Otherwise, you should get a professional to do it.

Here are the materials needed for the repair:

  • Face mask
  • Safety goggles
  • Gloves
  • Pencil
  • Measuring tape
  • Utility knife
  • Saw
  • Pry bar
  • Nails
  • Caulk

Follow the steps below to repair the rotten area and prevent further damage. 

1. Wear Protective Gear

Repairing the siding will involve small wood pieces that can harm your eyes and hands. Wear goggles and gloves before you begin the repair. 

Wear a mask as well to avoid inhaling mold in case it is present on the siding. Mold is a health hazard, so protect yourself. 

Check out this face mask on Amazon.

2. Mark the Damaged Area

You should mark the area that needs to be repaired with the pencil, then measure a foot wider than that area. Make vertical lines with the pencil so that the area is easier to cut.

3. Remove the Damaged Wall Siding

Remove the caulking around the wood siding with a utility knife before cutting the wood.

Using a saw, cut the wood following the vertical marks you made on the surface. Be careful not to cut too deep into the structure. 

Check out this compact hand saw on Amazon.

Pry out the cut wood with a pry bar. The nails should easily come out of the rotten wood. Be gentle in loosening it from the wall so as not to cause further damage to the surrounding areas. 

Check out this pry bar set on Amazon.

4. Check for Further Damage

Take the time to check for deeper damage once the wood is taken out. If the damage is bigger than what you first detected, it is best to consult with a professional repair company.

Do not cover the damaged area if there is a water leak or other problem which can affect the structural integrity of the house. 

5. Replace with New Siding

If the wall siding damage is just on the surface, then proceed with cutting a new section of the siding. Measure the open area to make a precise replacement.

Secure the new section of the siding with nails. Caulk any gaps on the siding as well. 

How To Prevent Siding From Rotting?

Close up of weathered wood siding beginning to rot around front step

Plant Care

Trim the plants hitting the wall to avoid moisture buildup. This will allow air to flow between the plants and the wall siding.

Always keep the plants one foot or more away from the wall. Do not let plants get too tall. This will prevent the wall from staying wet all the time. 

Apply Caulk

Caulking can be done around the trim and butt joints. Caulking can also cover gaps between the panels.

Be careful with over-caulking. Leave space where water can escape so the wood does not stay damp. 

Check out this clear latex sealant on Amazon.

Check the Siding Regularly

Home maintenance should not just be done inside the house. You should periodically check on your home's exterior, especially after heavy rain or snow. 

Proper maintenance will help you detect rotting on the wall siding. It can also help you detect leaks or moisture problems that can lead to major repairs in the future.


You should protect your home by applying waterproof sealant before installing any wooden siding. This will prevent water from seeping underneath the siding.

Check out this waterproof sealant on Amazon.

You can also apply paint that has a sealant and matches the look of your house. This will make it water-resistant by covering the pores of the wood.

Check out this white waterproof seal spray on Amazon.

Clean Gutters and Downspouts

Always check and clean your gutters, especially after a storm or rain. This will prevent water from flowing from the gutter and seeping through the walls.

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Water trapped on the walls can cause moisture damage on the sidings. It would be best if you cleaned your gutters at least twice a year to remove any blockage.

Cleaning will also show if any leaks are present in the gutter. Have the gutter repaired or replaced right away once leaks are detected.

Best Types of Wall Siding To Replace Wood 

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One of the most common wall siding materials is wood. However, when your wood siding rots, you may consider changing your siding to a more durable type of material, like the ones listed here.


Metal siding is popular, because it is sturdy and does not require a great deal of maintenance. Aluminum and  steel make good siding materials because they are resistant to rot, mildew, and corrosion.  

Note that these types of siding can be expensive. They can get dented, and their finish can fade over time. 


Choosing vinyl siding has its advantages. It does not require frequent maintenance and can weatherproof your house. Vinyl is a durable material that can withstand extreme weather changes. 

It's a more affordable option than metal siding. It offers ease of installation, since it is lightweight. You can also choose from different colors of vinyl siding.

Keep in mind that vinyl siding is susceptible fire and heat damage. It can also trap moisture that may cause damage to your home. 

Can Pests Destroy Wall Siding?

Close up termites or white ants

Although ants and termites do not cause wood rot, they can still affect the durability of your siding. They enter holes and gaps in the siding. 

Termites are wood feeders. They will create hollow tubes in your wall siding that can affect the structure. These tubes are hard to detect, as they are buried underneath the wall. 

One way to test for their presence is to tap on the wall. A hollow sound is a sign that your wall siding might be infested with termites. 

Another pest that causes damage to the wall siding is the carpenter ant. This pest prefers moist environments or rotten wood and can make colony nests in the siding. 

The presence of carpenter ants is often indicated by wood shavings on the ground. You will want to address this problem, as carpenter ants can cause severe problems to your siding. 

In Conclusion

Close up of weathered wood siding beginning to rot

Rotting at the bottom of your wood siding means there are underlying problems with moisture. You should remedy the problem immediately to avoid costly repairs.

If you are looking for more house maintenance information, we have these articles:

Should Wood Floors Match Throughout House?

Should Gutters Match Fascia, Roof Or House?

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