Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.
Vinyl siding can transform the look and feel of a property. It’s a wall option with many benefits, including durability, affordability, and ease of installation. However, it’s not without drawbacks because water can get behind the siding and cause problems.
When water gets behind vinyl siding, it could lead to mold growth, rot in the sheathing, damage to a wall’s foundations, and insect infestations. If the water damage is ignored, it could affect the structure’s overall integrity, leading to heavier and costlier damage over time.
The rest of the article will look at some dangers of allowing water to get behind vinyl siding. We’ll also cover how to repair the problem and how to avoid it in the first place.
The Dangers of Water Behind Vinyl Siding
Most home construction experts will warn against the dangers of allowing moisture to get behind your siding. A little water or some snow making its way behind the siding may not cause any damage immediately, but if the leak is sustained and goes unnoticed, you can expect the following problems to arise:
The sheathing in your walls is there to strengthen the wall, maintain a nailing base for the siding, and boost insulation. If water goes behind the siding and remains unnoticed, it can lead to the decay of the sheathing. The affected area becomes weaker and may be the start of structural issues for the rest of the property.
The water behind vinyl siding provides mold spores with the right environment to thrive. As bigger colonies form, the wall will become weaker overall. However, mold formation in your vinyl is not just a structural concern for your wall; it’s also a health concern.
Molds can cause the following health issues:
- Stuffy nose
- Itchy eyes
- Itchy skin
People living with asthma or severe allergic reactions to mold may show more intense reactions overall.
Foundation Wall Damage
Foundation wall cracks are a home owner’s nightmare, and yet, it’s a common effect of water getting behind vinyl siding. Water leaks can cause vertical cracks in a home.
If left unchecked, the cracks will only worsen, putting the rest of the foundation at risk. Even when the cracks aren’t a threat to a home’s structural integrity, they can look very unsightly and cost a fair amount of money to remedy.
As some of the signs mentioned above begin to take root, a pest infestation is bound to follow if the leaky vinyl siding is ignored. Many insect species thrive in a damp environment, especially when mold has taken root. Some of the insects feed on mold, while others rely on the conditions to reproduce and spread.
Beetles such as the minute brown, hairy fungus, and the foreign grain beetles are just examples of insects that feed directly on mold. Granted, these beetles don’t cause any harm to your property nor spread disease, but they can make your space unsightly.
Dust mites also thrive in these conditions, and unlike the beetles, they can trigger allergies, and respiratory problems as the little hairs on their bodies break off and disperse into the air around your home.
Faster Degradation of Vinyl Siding
Many vinyl siding manufacturers promise 20-30 years lifespan on their products. However, many of them often fall short of that time window as you’re sure to start seeing strong signs of wear and tear after a decade.
Water behind vinyl siding can bring the lifespan down even further. In some cases, the vinyl siding will quickly take on the discolored appearance if the water leak is ignored.
How To Know if Water Is Leaking Into Your Vinyl Siding
You can detect water leaks into your vinyl siding by watching for dirt-like residues inside your home—especially around the window area. Once you see this sign, call in a qualified contractor to run a moisture test on your home. They can complete the test without disrupting your schedule or distorting your home’s exterior.
How Contractors Repair Leaky Vinyl Siding
Contractors will figure out the right way to approach this repair job by first figuring out what’s behind the leak in the first place. They can approach this type of repair in various ways, but a general repair approach will involve the following:
- Close inspection of siding around the area that has shown signs of leaks
- Sealing of the siding area using some elastomeric caulk
- Gliding loose siding back into position using a vinyl siding removal tool
If the leak has already caused some damage, the project’s scope will expand to take care of the damage. You may also need to install some siding sheets to replace worn-down portions.
How To Keep Water From Leaking Behind Vinyl Siding in Future
You can keep water from leaking behind vinyl siding in the future by ensuring the siding is installed correctly from the start. Here are a few pointers.
- Start from the bottom and work your way up.
- Successive siding strips have to overlap the previous one’s top edge.
- For vinyl trims around doors and windows, the under-sill trim goes on first before the side trim.
- Install corner units and other accessories first.
- Lap all joints effectively.
- Exercise caution when installing new siding over an old one.
In addition to the tips above, you should pay attention to the building codes in your area. You may be required to install a moisture barrier between the siding and your house boxing.
You’ll need this if heavy winds are a common occurrence in the area. When the winds force rain beneath the vinyl siding, it’ll run down the barrier without percolating. You should also keep your downspouts and gutters devoid of any clogs.
Water getting behind your vinyl siding is bad for the structural integrity of your home. It can encourage:
- Mold growth
- Rot in your sheathing
- Pest infestation
- Foundation damage
However, regularly checking the siding’s J channels—especially after heavy rains—and acting quickly to plug any leaks can prevent serious damage. Talk to a professional contractor if you suspect water leaks in your vinyl siding.
- Complete Basement Systems: Foundation Cracks – The Good, the Bad, and the Ugly
- CDC: Basic Facts about Mold and Dampness
- The Seattle Times: How to stop rainwater from running behind house siding
- ServiceMaster Restore: Water Leaking Behind Siding? 6 Steps To Take Right Now
- SFGate: How to Prevent Water From Flowing Under Vinyl Siding
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