How To Cut Off A Window Sill Perfectly In 2022? Let’s Do Some Crazy!

Rotting wood of the window sills isn’t something that you can put off to repair  tomorrow and have a goodnight sleep. It can cause a disaster to the decoration and structure of the wall causing it to fall apart after a time. But the good news is that if you take care of this now you’ll be doing yourself a favour. And if you decide to be a handyman yourself today, you might be wondering how to cut off a window sill.

Well, if that’s the case, shall we lend a hand?

You’ll need to start off by observing the condition of the window sill. Then, cut underneath the window sill and pry the trim. After that, remove the finishing nails and the side window trim. Loosen underneath the window sill to make it easier for you. Also, you can screw two nuts on the window trim to make it easier to remove. And at the last, finish it off with the finishing that you want.

how to cut off a window sill

Sounds promising? We’ve also got answers to the most frequently asked questions that you’ll face. So, let’s dive right in-

Grab These Essentials First!

It’s really important for home DIYers to know the right tools and the right quality of tools. Because quality tools are durable enough to handle your job and get it done right.

These quality products will give you the quality outcome for the job-

Utility Knife

You might also know this knife as the Stanley knife. It’s often used to help you get through narrow places that your hand or fingers can’t access.

Putty Knife

Putty knife is the tool that you use to apply putty where it’s needed and to smooth it. It might also help you get rid of extra stuff from the surface.

Pry Bar or Chisel

You might also know them as the crowbars or pinch bars. It’s main mission is to help you pull two objects apart by applying force.


Pliers are generally used for gripping something round like a pipe or rod. People also use it for twisting wires and some are designed to be used for a combination of tasks.


Sandpaper is used for the intention of removing material from surfaces. Also, it’s used to make the surface smoother or to make the surface rougher.

8 Easy Steps Guide on How to Cut Off a Window Sill

So, what’s a window sill, and what’s the use of it really? Well, it’s just like any other part of the window. Wooden window owners know how extremely decorative that simple window sill and the trim can look if it’s done right.

But the main purpose of the window sill is to prevent drafts and moisture from getting into your beautiful home. It also gives additional support to the window to stay in place.

So, let’s see the steps that’ll bring you success to cut off a window sill-

Step 1: Observe The Condition of the Sill

Before you even start, it’s essential that you observe the condition of your window sill.

Sometimes the sills rot because of the harsh weather on the outside. And in other cases, water leakage on the wall might be a reason.

There are two different types of rot depending on the causes of the rot. The dry rot and the wet rot.

(i).   How to Handle the Dry Rot?

Dry rots are a much common type of rot when you have extremely hot and dry weather outside most of the time. It won’t be that much of trouble to remove a dry-rotted sill as it’s still hard and dry.

(ii).   How to Handle the Wet Rot?

In most of the countries where it rains most of the time, dry rot is very usual damage to the wood.

When water leaks or stays put for a long time near the window, a fungus appears and starts the rotting. The window sill will become over moisturized and rotten.

If you try to move the sill with a wet rot, it’s going to be a massacre and there will be pieces of rotten wood stuck at places.

You can try and use a hairdryer and dry the place. It’ll take some time to dry the affected place but you’ll get the job done. It’ll be a lot easier to move the sill and avoid the mess if it’s well dried.

Step 2: Cut Underneath The Window Sill

The window sill is kind of sealed under the window. So, you need to cut underneath it to free the sill from the trim board that is under it. It’s the start of taking the sill apart from the whole set of the window.

Step 3: Pry The Trim

Now, you need to detach the trim. The window sill and trims are often sealed together for a better structure.

You need to grab your putty knife and put it between the wall and the trim. That’s the weak spot that you need to focus on and pry the trim away from the wall.

It might get really hard to move the trim often. In that case, you can use your pry bar or chisel to get the task done.

Step 4: Remove The Finishing Nails

Finishing nails are applied to ensure that the joint that your window sill has with the window gets more durable.

You’ll always find finishing nails getting rusty if they’ve been in touch with water for quite a time. So, you need to be careful when you take care of those rusty nails. We don’t want you to get a Tetanus today.

You need to remove those finishing nails if you want to take away the window sill from the whole structure. You can use a plier to remove the nails safely.

Step 5: Remove The Side Window Trim

Now, you need to open your window to make things easier to work with. Grab the putty knife, put it in the weak spot between the wall and trim.

Then, remove the side window trim. No need to go too harsh on the trims. We don’t want to break anything that’s not necessary to break.

Step 6: Loosen Underneath The Window Sill

The main intention is to loosen all the stuff that gets in your way while removing the window sill.

So, it’s time to wedge the pry bar or chisel of yours underneath the window sill and loosen it as much as possible.

Step 7: Screw Two Nuts On The Sill

When you just need to remove the sill without damaging anything else, it’s important for you to be very careful.

And for that, there’s a simple trick that you can use when you’re about to bring the window sill out.

All you need is to simply take two screws and screw them on the outer portion of the window sill. Now, this trick is going to provide you an additional support which will help you remove the window sill more comfortably.

You’ll need to use your pry bar and stick it to the screws and pull lightly. Soon you’ll have your window sill out.

Step 8: Give It a Finishing

If you’re going to replace or repair the window sill, this step is especially for you.

You need to make sure that you’re getting the exact measurement for the new window sill that you had on the older one.

Use some caulk and foam and place the new window sill. It’ll make the window sill more compact and stronger than before.

And if the damage on the window sill is repairable use the wood putty and repair the window sill instantly.

Frequently Asked Questions

What is the trim under a window sill called?

The trim piece that you notice below the window is known as the apron. It’s a decorative trim that you need to install against the wall right beneath the stool of the window. It just pops up the look of the house right away.

How much overhang should a window sill have?

It should overhang the front edge of the window frame at least 3/4 inch. You can feel free to add up to 4 or more inches to the depth. It mostly depends on how much overhang in front you want or require. Also, you should use a straightedge to draw the dimensions on the sill.

What is the difference between a window sill and a window ledge?

You see, the window sill is on the inside of the house. On the other hand, the window ledge is on the outside. You’ll find an outside ledge in the large apartment buildings. It can be made of concrete and large enough to bear a standing man.

What wood is best for window sills?

Ponderosa pine is what you’re looking for. It’s better than the poplar as it’s probably more prone to rot. You can also consider more decay-resistant woods.

How deep should a window sill be?

On average, the depths of window sills range from 2 to 8 inches. But the depth of the sill can be more or less. And that depends on custom fittings and style preference of yours.

Wrapping Up

So, that’s all we had on how to cut off a window sill. We admire that you’re trying to experience something on your own.

But always remember that there are professionals who can take care of that window. It’ll cost you a little amount but they’ll get the job done faster and in a more professional way.

You need to be very careful with the rotten wood and sharp edges of the wood. Those might seem harmless but might cause you cuts. So, take proper safety precautions.

A word of advice, keep the wood away from the touch of water. Sealing places with epoxy might prevent the water from getting inside of the joints.

Nevertheless, we wish you the best of luck taking care of the window sill.