Hidden Compartment in Everyday Door




About: I've always loved the feeling of satisfaction that accompanies finishing a new project, no matter what the material or method is.

There are two crucial characteristics that make any secret compartment successful at keeping your personal effects truly personal. The first is that the access point of the compartment must be hidden from sight. The second is that the compartment must be very easy to access. This is important as there may come a time where you need to access the contents of the compartment, but do not have time to dig something out of your yard or pry off some floorboard underneath the furnace. 

This instructable will show you how to create a hidden compartment that fits these specifications perfectly, allowing easy access to a well hidden secret compartment.

This Instructable will show you how to create a hidden compartment in a hollow core door. This compartment will be able to hold a standard sized hanging folder, which you may used to hide any relatively thin secret object. The compartment is incredibly easy to access, simply needing to be able to reach the top of the door either standing on the ground or with the help of a stool or chair.

Step 1: Materials

- Hollow core door
- Hanging folder
- Paint mixing stick (Got mine from Home Depot)
- Wood Glue
- Curtain rod mount/bracket about  ( Can also be replaced with small piece of wood if bracket cannot be found )

- Multitool
- Circular Saw (I used a plywood blade)
- Drill (With the smallest bit you own)
- Carpenter's file
- Small clamps
- Band clamps (or some way to keep the door still when sawing)

Step 2: Prepare the Door

The first step I took was measure out the side of the folder and estimated the size I want to give the slot. 

After I did this I measured the width of one of the paint stirrers so I could determine the how thick the slot should be.

I then used a ruler to mark off the slot that I wanted to remove that would make up the hidden opening. (I made the opening closer to the size of the door where the hinge is so that the hanging folder would not swing as much.)

Next I drilled a hole at the one of the four corners of the marked off slot so that I could tell how thick the top board was. 

After I drilled the hole I proceeded to drill holes at all corners of the slot so that when using the circular saw later it would be easier to stop sawing. 

Step 3: Cutting the Opening

Once I knew how thick the top board was I adjusted the circular saw so that it would cut to the correct depth.

For this next step I recommend asking someone for assistance as the target area being sawed is relatively small. 

Line the circular saw up with the long sides of the section to be cut and cut out to the drill holes created earlier.

After both cuts were made you will have most of the length wise cuts made except for the rounded out section that the circular saw could not reach. To remove this last bit I used the wood cutting blade of the multitool. 

Next to remove the thin sections of the top board I used somewhat of an unconventional method, I drilled multiple holes in a row to create a rough cut line.

For the last part of the removal of the opening I used a carpenters file to flatten and smooth out all of the cuts, especially the drilled line.

I did not take any pictures of this next part, but on the inside of the door you will most likely find a cardboard support system, probably in a honeycomb shape. You will need to clear enough of this cardboard so that the folder will be able to drop down into the door.

Step 4: Adding the Brackets

The next step is to add the brackets that will support the hanging folder. 

I used the curtain rod brackets shown, but these could be replaced with simple pieces of wood.

The first step to adding the brackets is to measure how wide the bracket needs to be on either side of the slot in order to support the hanging folder.

Next you need to cut either the brackets or the wood to fit the measured specification. Place the pieces in the slot and test the opening with the folder to make sure that the slot will fit the folder correctly. 

Then you should ensure that when the brackets are placed so that when the folder is placed on top at least the thickness of two of the paint sticks remains above the folder so that the cover will lay flush with top of the door.

Once you are sure that the bracket fit these specifications you can proceed to either epoxy the bracket on or use wood glue to attach it (depending on the material of the bracket).

Step 5: Creating the Cover

Measure the size of the slot and divide that by two. This is the length that the two paint stirrers should be cut to.

Take one of the remaining pieces of the paint stirrers and wood glue it together with the two measured pieces in order to make a one long cover board.

Clamp the pieces together to ensure a strong bond. 

Wait until the glue is dry according to the specifications and test the fit on the top of the door.

If your door is stained you may want to consider staining the cover so that the compartment is better hidden even from people looking from above.

Step 6: Attach the Door and Hide Your Belongings

The very last thing I did was tape the sides of the hanging folder so that nothing would fall out of the folder as the door is swung open and closed.

The project is completed now. You can simply attach the door to the doorway which it belongs to and begin to use hidden compartment to hide your personal belongings. 

I understand that the door does not match the framing as I my dad did not want me to attempt this project on one of our doors that  we use until I could prove that I could do it on a door I picked up at the local hardware restore (wonderful place for DIY projects).

This was my first Instructable so please let me know if you think there is anything that I missed or of any questions you may have and I am more than happy to get back to you.

Please vote for me for the Secret Compartment and Doors Contest. Thanks!



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    45 Discussions


    4 years ago on Introduction

    Love this idea! I will probably just use a hand saw for mine. I am not that worried about having a clean, perfect cut for this. No one will ever see it. Thank you for sharing!

    uncle frogy

    5 years ago on Introduction

    it would not be any harder to make a box out of fiberboard or paneling that would fit inside the cavity and fill the surrounding void with some spay foam insulation. if the "linerbox" was stiff enough and glued by the foam to the door skin it might mitigate the lose of integrity in the door caused by the modification

    uncle frogy

    spark master

    5 years ago on Introduction

    I must say I am glad someone took my suggestion. About a month ago a gent did an instructable on a hidden compartment in a shelf, I suggested that a hollow door woud work as well and we joked about it. Glad to see someone made one.

    You can use spray in place foam and cut pieces of wood slats (paint sticks as seen here aglue 3 to fit the space you want (to make a U) spray in foam and push in the U shaped wood. form Weight it down to make it stay in place, then follow this gents instructable. But that isn'n needed, just push the thing in after squirting in glue at the bottom of the area (my doors had honey comb paper in them). If there is no inner honeycomb, drill two holes in the sides of the u shape (before assembly) Glue up the U allow to dry, then apply glue to the edges (a good amount) so there is enough to stick the door skin to the Uframe, screw in place temporarily, then remove the screws after it sets. You could then make a "drawer " that sits in the door.

    nice instructable, thanks

    1 reply

    Hi spark master,

    I honestly didn't even see your original suggestion, but it sounds like you've come up with some great ideas for the implementation.

    Thanks for the comment


    5 years ago on Introduction

    I forgot to add something else. Instead of us a circular saw a person could use a jig saw. There would be less mess and you would have more control over cutting. Thanks for sharing your idea!

    1 reply

    I first tried a jig saw on the project, but I ran into trouble as I was on my own doing the cutting and the door vibrated to the point where I could not make a clean cut. So i opted for the longer straighter cut of the circular saw.

    I suppose with better support when cutting the jigsaw could be much easier.

    Thanks for the tip!


    5 years ago on Step 3

    Why is the slot so much wider (fatter) than the folder? You lose the strength of the door.

    1 reply

    Reply 5 years ago on Introduction

    This was mostly just to match the approximate sizes of the paint stirrers and the hanging brackets I had. I also thought that it may be difficult to grab the folder if the opening was too narrow. The width could be made much thinner to keep some of the door's strength, but I simply chose what I thought fit my needs best.


    5 years ago on Step 4

    Is your door empty? I thought they had paper honeycomb in there.

    1 reply

    Reply 5 years ago on Introduction

    This door did have some cardboard strips that zigzagged down the insides, I forgot to elaborate in the instructable. I'll be sure to mention that. Thank you


    5 years ago

    I like the idea, but have to ask.... with a swift opening of the door, does the hidden compartment folder flap around inside the door to audibly give away that there is something inside the door?

    4 replies

    Hi thanks for commenting.

    I considered this as a potential problem and I attempted to address it by placing the opening on the side of the door closest to the hinge so there would not be as much velocity as near the outside of the door.

    When I used the door I did not notice it, but I only kept light objects in there such as papers. I suspect that if a heavier/harder object was kept in the folder it would make some noise.

    David Catriel's idea is great, I didn't even think of using padding, but some foam on either side should elimate most if not all noise.

    David Catrieljec0435

    Reply 5 years ago on Introduction

    The easiest way around this would be to buy foam sheets (the kind used to stuff pillows) and add them to the folder so that it takes up the entire width of the door.


    5 years ago on Introduction

    Nice idea but two things came to mind:

    1) mentioned by another commenter) the door is weakened by cutting out the topmost wooden support, this might have a lone-term affect on the closing of the door - especially if you've got kids that like to hang on door handles to swing on the door!

    2) There's a high possibility of putting the folder into the space at an angle and small things falling out of the gaps at the ends - maybe tape them up or a few staples would be sufficient.

    3) What happens if the folder falls down inside the door? it could be great fun to get it out again!! :-))

    1 reply

    Reply 5 years ago on Introduction

    Hi agulesin, when I started this project I knew that the strength of the door would be weakened, but I suppose I figured it would most likely be on a closet door that is not used nearly as roughly as a entrance door to a room.

    About things falling out of the side I did mention taping the sides of the folder, but it was kind of added as a afterthought, so I can see how it may have been missed. (I almost couldn't even find it, its in the last step).

    With the folder falling down inside the door I tested it on my implementation, and the only way it would fit through the gap was if the folder was severely warped or put in at over a 45 degree angle, which I imagine would not happen often.

    Thanks for commenting