No House Wrap Under Vinyl Siding? Here’s What You Need To Know

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Last updated on January 15th, 2024 at 09:38 am

Benefits To Installing House Wrap Under Vinyl Siding

Replacing your siding and realizing there’s no house wrap underneath? Now you’re wondering whether you really NEED to install it before continuing to install new vinyl siding? Well, look no further because I have your answer!

Installing house wrap under the vinyl siding is necessary to protect the exterior of your home from moisture damage, mold and mildew growth, and drafts of wind throughout the home. House wrap is an inexpensive and easy-to-install product that will protect your home and help reduce heating and cooling bills.

While we were replacing our vinyl siding, we realized the old wood siding underneath had nothing overtop to protect it from the elements (and definitely looked worse for wear because of it).

So we spent the extra time and money to make sure we protect our home for years to come. Let me further break down why doing this will be worth the little bit of extra time and money for you.

Let’s dive in!

Quick Navigation: House Wrap & It’s Purpose

  1. Moisure Damage
  2. Drafts
  3. Mold and Mildew Growth
  4. Other FAQs About Installing House Wrap Under Siding
  5. Final Thoughts
  6. Related Vinyl Siding & Outdoor Articles

What Happens If There Is No House Wrap Under Vinyl Siding?

House wrap is an easy and relatively cheap way to protect the exterior of your home. Without it installed under the siding, a few problems can occur:

  • Moisture Damage
  • Drafts
  • Mold and Mildew Growth

Moisture Damage

One event that can happen if there is no house wrap under your siding is moisture damage.

Oftentimes, the siding itself is not waterproof (for example, vinyl siding is not waterproof). The siding deflects most of the water from rain and snow and gives the little bit of water that can get behind it a clear path to drain off of the house (typically through small drainage points along the bottom).

To help prevent that little bit of water from damaging the wood behind the siding, you would install house wrap.

Without the house wrap, however, water can become trapped and make the structure of the house swell and become waterlogged. Over time, the structure of the house can break down and/or invite other pests and critters to come and feast on the rotting wood.

what happens if there is no house wrap under vinyl siding
Water got directly behind the vinyl siding here and damaged the MDF that covered the exterior of our garage. House wrap would have helped prevent or minimize the damage.

Related Siding & Outdoor Articles


Another event that can happen if there is no house wrap under your siding is a draft inside your house.

Wind can easily get through the siding and cause a cold flow of air to go through your house. This is because vinyl siding is designed to shift and flex with the wind to avoid cracking the siding.

Vinyl siding also allows air to flow through it so that any water that does get behind it can more easily dry out. While this is a good thing that vinyl siding allows this type of airflow, it is also a problem for the temperature of your home.

This can be costly to heat your house in the winter and cool your home in the summer. However, when house wrap is installed and the seams are taped, it creates a barrier to minimize the flow of air both into and out of your home.

That, in turn, helps lower your heating and cooling bills while also protecting the exterior of your home. Score!

Benefits To Installing House Wrap Under Vinyl Siding
We taped off the seams to help minimize drafts in the house.

Mold and Mildew Growth

Finally, another event that can happen if there is no house wrap under your siding is mold and mildew growth.

Along with the potential for water damage, any water that does get trapped behind siding is the perfect breeding ground for mold and mildew.

While mold and mildew typically don’t cause damage to the things it grows on, it can wreak havoc on the health of any individuals who are allergic to it and live around it.

And because the water is being trapped behind the siding, it might not always be obvious that there is growth happening along the outside of your home.

House wrap helps to deflect the water away from the home and dries out quicker than wood, so isn’t the best breeding ground for these spores. Therefore, it helps to minimize the potential for this problem.

Other FAQs About Installing House Wrap Under Vinyl Siding

Here are some other frequently asked questions about whether or not you need house wrap under the siding to help you decide the best course of action for your unique situation!

Does Water Get Behind Vinyl Siding?

Water does get behind vinyl siding. Vinyl siding is created to shift and flex with the sun, wind, rain, and snow to prevent cracking and warping. This mobility allows water to get behind it, but it does have small drainage points along the bottom so that water can easily escape and airflow can dry out the backside of the siding.

Do You Have To Replace House Wrap When Replacing Vinyl Siding?

House wrap only needs to be replaced when replacing vinyl siding if the existing house wrap is damaged. If there are large holes or tears or the seams aren’t taped anymore, then replacing the house wrap is necessary to help prevent future water damage, mold/mildew growth, and higher cooling/heating bills.

Can You Put House Wrap Over Existing Siding?

House wrap can be installed over existing wood siding. Tacking the house wrap directly to the existing wood siding can provide another layer of protection for the exterior of your home. New vinyl siding can then easily be installed over the existing wood siding.

In fact, that’s what we did to our home. The previous owners installed vinyl siding directly over their old wood siding, but they didn’t install house wrap between the two.

So when we replaced our vinyl siding, we left the old wood siding and installed new house wrap and new vinyl siding over top to give a double layer of protection and insulation to the bones of our old home!

can you put house wrap over existing siding
I don’t know who decided a pink wood house was a good idea, but I’m glad it was covered up by siding haha!

Final Thoughts On House Wrap Under Vinyl Siding

There you have it! Installing house wrap under your siding can save you money over the years that you own your home.

Plus, it is relatively inexpensive and extremely easy to install. So if you are replacing your siding, it would be in your best interest to install some house wrap as well.

We love feeling confident that our home will be protected for years to come!

is house wrap necessary
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No House Wrap Under Vinyl Siding? Here’s What You Need To Know

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