When people are building their homes and isolating their homes against adverse conditions, one of the most vulnerable spots for possible leaks is window openings. For this reason, it is crucial to know how to install window flashing tape in order to prevent any leaks and potential damage.

Consider this a long-term investment of your time and money. It is wise to do it expertly and with proper materials rather than save money on something so important. Many people neglect the importance of flashing a window, so they don’t even do it, or they don’t do it properly. Knowing how to install window flashing tape properly is one of the more important tasks when it comes to isolating your house.

Firstly, it will prevent the unwanted airflow from entering your home, which can prevent cold air from coming in through the window opening in the window, and provide better protection against warm air in the summer. Also, it prevents any potential leaks that can cause further damage to your home. In this article, we will take a look at how to install window flashing tape properly to protect your windows.

Window Flashing is Vital for Protection

window-flashing How to install window flashing tape with no mistakes

Some people ask themselves why is window flashing even important? The answer is that it can help you avoid the unwanted effects of water leaking through the cracks and the openings of your window. That in itself is a scary thing, but what is even worse is the fact that it can cause rot, damage to structures and materials, mold, and insect infestation. Without window flashing, those phenomena are just invited to your home.

What happens is that when the water slides down the wall, it tends to go right through even the smallest of cracks in your window opening, so it is inevitable that it will enter your home. The window flashing is the next line of defense. Without it, moisture and mold can enter very easily, causing even more damage to your home.

Having window flashing is essential for stopping rain from entering your house through the window opening, which can happen especially in the case of strong winds. It can even protect your home from moisture entering your house. Knowing how to install window flashing tape is necessary if you are working alone, but it is not only recommended, but in some areas, even required to have window flashing tape installed.

When to Install the Flashing

flash-type How to install window flashing tape with no mistakes

The next question is, when do I install the window flashing? Preferably, it should be installed at the same time as the windows are put into the window frames. It is a two-part process; the first part is when the window opening is prepared for entering the windows in them, and the second part comes right after the installation of the windows.

So what are the types of window flashing that you can install? After all, you will have to decide what type of flashing you will install. There are three main types of window flashing:

  • Tape Flashing. This is the most common type of flashing as it is possibly the most flexible and durable material out there. It is a relatively new concept that is quickly catching on for new constructions.
  • Sheet Metal. When we talk about metal for window flashing, we think of the really thin layer of metal that will cover the possible openings. It is a very flexible material.

vinyl How to install window flashing tape with no mistakes

  • Vinyl. Another very popular material, as it is relatively affordable and durable, and is often used in combination with vinyl siding. Its drawback is that it is not as suited to extreme weather as other materials.

Since the 1970s, window flashing tapes have been in use for new households, although in a very different form than today. At the very start of this concept, siliconized paper membranes were at the heart of the flashing protection; nowadays, it has evolved a lot, and we see it mostly in the shape of other, more sophisticated and more effective materials.

Choosing the right material is crucial for the installation to adapt to the conditions in your area; what you should consider are the temperatures in your area, the overall weather conditions and in the case of adverse weather, how bad it can get. It should also be compatible with other materials used for windows.

What to Consider Before Flashing the Window


flashy2 How to install window flashing tape with no mistakes

The first and most important thing you should consider is the weather conditions and the temperatures in your area. That is because some materials are better suited to some weather conditions than others. Some will, for example, become less sticky in temperatures of 50 degrees Fahrenheit, while others will not be suited for those temperatures at all. Some materials are better for lower temperatures than others.


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Also, you should consider which products stick to certain materials and products, which is normally specified by the manufacturer. Some will require special attention to this issue, while most will be fine.


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Every product you use should be suitable for using it with the “shingle principle”. That means that upper materials should overlap the lower materials, which will enable the water to flow down, and away from the building. Taped joints are not the best option for this method, so you should choose the material that will make it possible to create the flashing in this manner.

How to Install Window Flashing Tape

cutting1 How to install window flashing tape with no mistakes

Installing the window flashing tape requires a lot of precision and patience. In most cases, you will get instructions from window manufacturers, and the instructions will depend on the different materials that are in use. If you can, follow the manufacturer’s instructions for installing the flashing. Here are the steps of how to install window flashing tape.

  • Start with cutting the building wrap that is over the windows. This tape usually covers windows as well, so you will need to uncover them in order to install the tape. First, make an X cut where your window opening is, and cut the wrap across the sill. Then, you will need to wrap both jamb sections into the rough window and attach it with staples. Make two 45-degree cuts at the header section and fold the wrap upwards. Hold it in place with staples or tape.

measureing How to install window flashing tape with no mistakes

  • The next step is very important, and requires a lot of precision. Measure the window openings or door openings and write down the figures. Be precise, as it will allow you not to waste materials. Then, you will want to cut the tape according to the measurements, which is equal to the length plus about 3 inches for taping.
  • Make sure that the surfaces where you will be applying the tape are clean and dry, which will make the installation much easier. Also, it is important to use high-quality tapes.

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  • Start installing the tape from the bottom towards the top, and use the shingle method. This will prevent the water from entering, and the water will flow away from the window or doors.
  • The next step is to peel the paper and expose the sticky part of the tape. Then, press the tape so that it fits completely into the part where you want it fitted, so that it stays in place.

shingles How to install window flashing tape with no mistakes

  • Then, you will need to roll the tape along with the opening, which will slowly let you remove the paper from the tape. Start at the bottom of the opening, and be careful with corners. Also, press down on it in order to fit it properly and to prevent wrinkling. There will be 3 extra inches at the side to allow for easier fitting.

lastpoint How to install window flashing tape with no mistakes

  • Staple the edges of the tape, which will give it extra security.

Additional instructions on how to install window flashing tape

  • The rough openings of the windows will allow the house wrap to lap inside, which will make the installation easier.
  • The house wrap should be installed as best as possible to make the taping easier.
  • Install a pre-fabricated sill pan under windows.
  • In some cases, you will need a second taping.
  • Third taping can be used across the window top.

Hopefully, you now know how to install window flashing tape with no mistakes.

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