How to Install Vinyl Siding Around Windows [2 Simple Step]

How to Install Vinyl Siding Around Windows

Vinyl sidings have been receiving a lot of popularity in recent times by contractors, modern architects, and people in general who own a house. There are various reasons why vinyl siding has become the preferred choice over aluminum, timber, and other cladding materials. But there is still something that causes difficulty among people while installing vinyl sidings. The question of “How to install vinyl siding around windows” remains a big challenge for people who wish to have vinyl sidings. 

The windows have to be properly covered from all edges to create a perfect finish that keeps away water leakage and also looks good. This difficult-looking process can be made easy if you know the right things to carry out in vinyl siding installation.

The process is divided into two important parts: the first is the cutting and installing the molding and the second is cutting and installing the sidings.

It is quite easy to know how to install vinyl sidings around windows if you follow the steps given below. 

Step 1: Cutting and Installing the Molding

1. Review flashing and building wrap

Have a good look at the flashing and building wrap around the window. See to it that the flashing at the vertical sides of the window is overlapping the bottom flashing by about 2 inches. Also just above the window, the building wrap should be overlapping the flashing by 2 inches. Make sure these things are done right so that you can move forward with a lot of ease.

2. Cutting the J molding

Now you need a J molding around the window to cover it from all sides. Cut the J molding 2 inches longer than your sides of the window using a tin snip or any other cutting object. Also cut a 1-inch notch and both ends of the J molding. Once you are done with this, then you can cut out the remaining material.

3. Installing the J molding

After cutting the J molding properly according to the size, you can install them using nails. Start doing it from the bottom of the window. Make sure to leave some space when nailing the moldings so that they have some space to expand. Then you can install the J moldings on the two sides. The 1-inch notch should overlap the button J molding from both sides. Do the same thing similarly with the top side of the J molding.

Step 2: Cutting and Installing the Siding

1. Measure the vinyl sidings 

 We now come to cutting and installing vinyl siding trim around the window. Hold the piece of siding below the bottom of your window and measure it properly by keeping some space extra at the ends for expansion(¼ inch recommended). After that measure, the J molding from its inside top and subtract the inches of extra space you had kept for expansion. Mark the point from where you want to cut the siding and make notches at end of your created marks.

2. Fitting the sidings in the J channel

Now you can fit your vinyl sidings into the J molding starting from the bottom of the window. If so far you have done everything right, then the sidings will fit perfectly into the J channel. The space you had left for expansion will help the siding to fit in properly.

If in case the siding does not fit properly then you can remove the notch part and install an undersill trim inside the J channel and then fit the top of the notch into the undersill.

You may also like: How to cover windows to keep cold out

3. Install sidings on every side of the window

Keep installing the vinyl sidings on all sides of the windows. Remember to keep some extra space at the ends which go through the J channel. Fit all the sidings properly and then nail them loosely.

Pro Tip

Install a drip cap at the top of your window to keep all the draining water away from your window. The dripping water could cause rot in the vinyl sidings so it is recommended to do this. Install the drip cap the same way the J channel was done.

Items and Materials Needed for the Whole Process

Tools required

  • Hammer
  • Nails
  • Tin Snap
  • Pry Bar
  • Measuring Tape
  • Utility Knife
  • Tool Belt

Material required

  • Aluminum Flashing
  • Building Wrap
  • J Channels for Molding
  • Vinyl Siding
  • Undersill
  • Drip Cap

The Pros and Cons of Vinyl Sidings

It is no doubt that Vinyl sidings are very much preferred by people and contractors all around the world but they too have their sets of Pros and Cons which should be considered before installing them.


  • One of the best things about vinyl sidings is that they keep the heat and cold out of the house.
  • The body of Vinyl sidings does not need to be repainted, the color stays for a long time. 
  • The material is very durable and long-lasting and so there are very low chances of it rotting
  • Economically these are very inexpensive and are good for maintenance.
  • They are available in lots of colors and finishes that give your house a very stylish and premium look.


  • You might have to sacrifice some architectural features that you want in your exterior.
  • Can be counted as a lower quality material with respect to other options in the market.
  • Though Vinyl has less carbon content still is a kind of plastic and is hazardous for the environment.


Can you paint vinyl sidings?

Yes, painting vinyl sidings is possible by first adding a layer of primer on it and then the paint. But it is better if you replaced the sidings in the color you want because vinyl sidings are not meant to be colored.

Can vinyl sidings keep away bugs?

Yes, it is quite evident that vinyl sidings can keep away bugs and insects from your house unless you keep your windows and doors open frequently.

Can vinyl sidings be installed on an RV?

No, vinyl sidings are fitted quite loosely and so there are chances the sidings will come off when the RV hits the road.

Does water seep through vinyl sidings?

If the vinyl sidings are installed properly without keeping any gaps then they can keep water away from your house. You should keep a check on your house now and then to see if any siding is damaged or needs to be replaced.


That brings us to the end of the article. By now I’m sure you have understood how to install vinyl sidings around windows and also the various details to keep in mind while carrying out the process. Go through the steps one by one whenever you are installing vinyl sidings around your house and you will definitely achieve the perfection you came looking for when you found this article.