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DIY Windowsill shelf for Cats, Kids & Plants

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Windowsill shelf for Cats, Kids and Plants

Using Spalted Maple (but you don’t have to)

cat footprint hires22 12 1

Super Simple DIY Windowsill shelf for cats, kids and plants

Lifetime of memories for a few hours of work.


Our first home had a window that overlooked our backyard. In fact, the CraftyCatsman was birthed from this window (ew). What I mean is, we built a two level Catio under this window. The top level was always stocked with food and water. A number of neighborhood cats would find their way to the food to eat.  In the mornings, our first stray would come home to eat breakfast with our daughter. 

Our current cat window perch for narrow sills just was not cutting it and so we decided that we needed a cat window perch for large cats (and kids alike!). We tried the cat window perch suction cups method but it didn’t allow any room for our daughter to sit and enjoy the views with her best friend. 

This windowsill shelf needed to support these breakfasts and so I decided to take on a very simple, quick and cheap DIY windowsill project. Typically, my projects are pre-approved by the wife. Truthfully she didn’t want this at first but after I dry fit the finished product she quickly changed her mind. 

We have since moved from this house but every day for over a year we had the opportunity to watch our daughter grow alongside her best furry friend during breakfast at the slab wood bar. 


A Catio is a great way to support stray cats. It provides shelter and a warm place for them to stay. We trap and release stray cats. This gets the cats the shots they need and it also prevents them from having (adorable) kittens. If a stray cat has a notch off of one ear that means that it was already trapped and released. 

kid eating with cat. Toddler and cat breakfast. Cat Charity. Kids bib
kid in pajamas feeding pet
spalted maple diy bar
Kid and cat eating at a window.
can of fancy feast product photo

Wet Food

DALL·E 2022-08-17 13.48.26 - _scrappy bro cat with hat and headphones and Dewalt safety glasses_, _sitting at a workbench with a clipboard_, _scrappy bro cat checking red boxes on

Categories and Difficulty

Every Project is ranked by Tool Category and Difficulty Level.

Click below to learn more

DALL·E 2022-08-17 09.54.10 - scrappy bro cat with hat and headphones and Dewalt safety glasses, walking through a brick alley between two row homes, holding a drill, cinematic lig

alley cat

How do you make a window shelf for a cat?

1. Scope the space: determine your dimensions

2. Find a piece of slab wood: Beauty is in the eye of the beholder. Just make sure it’s wide enough.

3. Cut the slab wood to fit your windowsill

4. Sand the slab wood windowsill down and stain it

5. Secure the new wood to the sill using wood glue and a few wood screws in the corners (hid the screws with planters).

Do cats like window perches? Absolutely! It gives them stimulation. It is one of our adopted strays favorite places to sit. A cat window hammock or a cat window bed are great ways to achieve this but we feel that our cat window perch is the perfect addition to any window. It accommodates larger cats and kids alike :).

It’s 2023, the year you put you in Do it yourself. Let’s dive in below!



Spalted Maple Slab live edge

Cut notches if necessary

Using a scroll saw, band saw or hacksaw cut notches out if necessary. 

Our Breakfast bar needed the notches to fit snugly against the window.

toddler watching woodworking. Sander on a piece of wood.

Sand with Supervision

Toddlers work well

Spalted maple wood window sill

Test the Fit

Windowsill shelf for Cats: Tools

Affiliate links:

If you click through any of the below links then I may receive a small compensation from Amazon, even if you go on to buy something else. This is a great way to support the site without actually sending me money :). 

Ryobi Circular Saw product photo

Circular Saw

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Note On Tools

In photography they say that the best camera is the one that you have with you.

In woodworking, you can do a heck of a lot with the most basic and inexpensive tools. That being said, the more that you have available to you the quicker you may be able to finish a task. 

For example, an orbital sander will eventually get rid of band saw lines while a belt sander will get the job done a heck of a lot faster. 

My projects have a tool rating that can help guide you on what you need. Check it out by clicking below

Windowsill shelf for Cats: Materials 

If you don’t have scrap wood, look on facebook marketplace for a hardwood that is at least an 1″ thick. The length depends on your window sill. 


Step 1: Scope the space

A windowsill shelf for Cats, Kids and Plants starts with a little recon work. Hopefully without the raccoon!  

grey cat and raccoon

We have detachment issues

As mentioned, this project was not wife approved. If it was up to her we would have just purchased a K&H Pet Kitty Sill (great product, we have one upstairs).

As such, I decided to see what the project would look like if I didn’t remove the existing sill. See the above picture for reference. It was skinny and pretty beat up.

Part of what makes this project so simple is that you are going to put your slab right on top of the old sill.


Rocco (our website mascot) was trying to explain this to the neighborhood raccoon. 



Step 2: Slab shopping

live edge spalted maple unfinished

My windowsill was about 3 feet wide and I happened to have some scrab spalted maple laying around that fit perfectly. The entire slab (pictured left above) was $75. I had used the majority of the slab for another project and happened to have this left over.

If you have read some of my other posts you will notice that I mention using “scrap” slab a lot. This is because when I find a good looking piece of wood I always buy it longer than I need. I know that I will find a use for it later on. 

Slabs are sold by the board foot and they start to get pricey when they are wide enough to be a coffee table. The more narrow boards tend to go for cheap because a lot of people snatch up the wider boards. Thankfully this windowsill shelf for cats doesn’t need to be. We actually used some of the scrap to build a cat window seat for Bubby to sit on while he ate. 


Fine by us, we only need a slab thats 10-18″ in width.


Spalted Maple is a bit tough to work with but it’s not impossible. There are a few extra things to do that I will highlight later on. 

How to Shop for Slab Wood
Buying slab wood is a fun process, finding the right opportunity can yield you enough for multiple projects on the cheap. 
I wrote up a brief guide on slab shopping, click below to learn more.

Step 3: Cut to Length

I cut the sill to length and then put it on top of the old sill. 

My window had two edges (one on each end) that I had to account for. 

I marked the end of each edge and then measured the depth. 

I cut notches out with my scroll saw but a band saw or hacksaw would work fine. 

Test the fit of the sill. 

My existing sill was very narrow, because of this I couldn’t screw from the bottom up. I had to screw through the new sill into the old one. I covered the screw holes with planters but if you hate this idea you could try using wood glue only, though I don’t recommend it. 

If you want to follow my lead then at each end screw two (2) wood screws through the top of the new sill and into the old sill. 

Remove the screws and set them aside for a later step.


Dear Spalted Maple - I love you

Spalted Maple is downright sexy and it is one of my favorite woods to work with. In fact, I built a full bartop off of a beautiful piece of spalted maple that I bought for $85. 


The dark lines and character exhibit on the board is actually from the partial decay of the wood. You know…fungus.


You need to find wood that has a good amount of decay but not too much to ruin the integrity of the wood. You also want to be absolutely certain that the wood was air dried or kiln dried (preferred).


If the wood is dried then nothing you can see will be of concern – just seal it with polyurethane to trap those beautiful lines in.


When shopping for spalted wood make sure to feel the board for soft spots. It’s fine if the edges are brittle, you can always sand them off. 

Spalted Maple Slab live edge

Step 4: Sanding and popping the grain

kid watching woodworking
How to sand live edge with an Orbital Sander

Start with an orbital sander with 80-grit sandpaper. 


Go in the direction of the grain (follow the lines) If the wood is too rough you may need to use a belt sander first.  


The issue with a belt sander is that you risk sanding unevenly. If you are belt sanding then do your best to keep the sander moving.  


I also enjoy making my own “live edge”. A traditional live edge has bark on it but instead of that, I like to sand one side down by running my belt and then orbital sander in random half moon patterns. This gives the edge a natural look but one that is more refined than traditional live edge. It worked perfect for the windowsill shelf for cats.


After using 80-grit switch to 120-grit to smooth things out.

New to Sanding?

Embarking on a windowsill shelf for cats but unsure how to get things nice and smooth? Check my sanding 101 post by clicking below.

I always recommend popping the grain of the wood but with maple I strongly suggest that you take my advice. 


After the wood is sanded pour water on it and wipe it down with a rag. Let the wood dry (cat supervision optional)


Sand with 120 grit.


Note: the above picture shows the two screw holes that I made on the end of the board. 

cat on wood. grey cat on maple wood

Step 5: Finishing

cat footprint hires22 12 1
How to apply polyurethane - toddler with safety glasses

Maple is notorious for blotching during the finishing process. Blotching is when the stain or finish (like polyurethane) dries unevenly creating unsightly eye catching blotches on the surface of the wood. 


I have used maple in plenty of projects and to prevent blotching I follow the following rules. 


1. Always pop the grain (see above step).

2. Use an oil based pre-stain conditioner for warm tones or a water based for cool tones.

3. Avoid staining. 

4. Apply polyurethane that matches your pre-stain conditioner (i.e., water or oil).


Maple is beautiful in its own right and I never felt the need to stain the wood. That being said, you can control the color tone with the type of polyurethane that you use. 


This is a windowsill shelf for cats, kids and plants and I wanted it to exude a nice warm tone. Because of this I chose an oil based pre-stain conditioner as well as an oil based clear semi-gloss polyurethane. If you want a cooler tone (more white) then opt for a water based conditioner and polyurethane.  


You may be thinking, why use a pre-stain if you aren’t staining? The pre-stain conditioner is a different consistency than your finish which allows it to penetrate the wood more deeply – this extra layer aids in the even absorption of stain / finishes. 


If you want an even warmer tone then I suggest that you check out Minwax’s oil based warm semi-gloss. I used it on my spalted maple bar top and love the way it turned out.

Poly what?

Polyurethane is an easy to apply protective coat that is commonly applied to wood.

Click below on more details on how to properly apply Polyurethane. 

conjunto de la pista del clavo del metal 27990620

Final Step

Windowsill shelf for cats: Secure wood to the sill

As mentioned in the beginning of this post, I didn’t want to cause any permanent damage to the window (besides a few screw holes). 


I decided to secure the wood to the sill with wood glue and some wood screws. 


1. Clean the existing sill

2. Apply a generous amount wood glue to the top of the existing sill

3. Fit the new wood on top of the sill and put some heavy things on it. I put a few full paint cans.

4. Screw the 4 wood screws back through the top of the new wood into the old sill. 

5. I decided to cover the screw holes with planters

6. Step back and enjoy!


Remember, while polyurethane dries in a day it doesn’t fully cure for almost a month. You can use the new sill but I wouldn’t eat off of it for at least a month. 


My writeup’s are more wordy then most, mostly because I try to write out what was going through my head during a project. 


It’s extremely rewarding to know that I helped someone else get through a project so if I did please share your finished product (and/or progress photos) with me via email ( or by tagging me on Instagram (@thecraftycatsman).   


I may even feature your post or pic on the website.    


Thanks for reading!


The sill was made with scrap wood but even after this project I had a littttle bit left.  


I decided to make a bench with what I had left from this wood as well as a small off cut from a barn beam that I cut in half. I used my K40 laser engraver to put a logo on it. 


I made it in haste, maybe 30 minutes of thought and effort so it’s not my sturdiest project but it does look great and our cat still loves to sit on it. 


I will post a link to that project here soon.

Great Job finishing the windowsill shelf for cats project! 


My writeup’s are more wordy then most, mostly because I try to write out what was going through my head during a project. I also try to highlight parts where I learned from my mistakes (like the poke and pray method). It’s extremely rewarding to know that I can help someone else get through a project and I truly would love for you to share your finished product with me via email ( or by tagging me on instagram (@thecraftycatsman). I may even feature your post or pic on the website.


Thanks for reading.

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