This is a hidden crawlspace access door that I built into my bedroom closet floor. It allows my crawlspace to now serve as a storm shelter, a safe room(a place for my family to hide in case of an intruder), and a storage area.
I built it 2-3 years ago and it has been opened and closed 100's of times with no signs of wear and tear. The door is so well hidden that even I cannot see it when it's closed, and I know exactly where it is. There is no handle needed, you simply pull on the carpet to lift the door.
The scariest part of taking on a project such as this is cutting through a perfectly good floor. Who wants to be the guy who screwed that up, right? In steps 1 & 2 I explain a full proof method for marking & cutting the door opening precisely & accurately.
Piano Hinge @ $6
Barrel Bolt latch/lock @ $3
Double Sided Carpet Tape @ $5
Rubber door seal @ optional
Handle for underside @ optional
permanent ladder @ optional
scrap 2x4 @ free
1/8" or smaller drill bit
5 BBQ skewer
Step 1: Mark Opening
1) You need to find a suitable area you would like your secret door to be located. (Your floor joists will ultimately determine precisely where the door can be located)
2) Once you have found a suitable location, drill a very small hole through your floor.(1/8" or smaller) This hole should be roughly in the center of your door location. Slide your BBQ skewer 4-5 inches into the hole and secure it. If the skewer does not slide through completely, you may have hit a floor joist. Drill another hole 2" away and try again. Warning! Do not allow the carpet to twist around your drill bit. Don't worry about the hole, the carpet will hide it. Trust me; if you pull out the skewer, you may never find the hole again.
3) Go into the crawlspace and find the skewer. Now that you know which floor joists your secret door will be located between, drill 4 holes up through the subfloor.
- Measure out 1 1/2 inches from the joist and drill a hole up through the subfloor and carpet. Drill a 2nd hole 1 1/2 inches away from the same floor joist 10 inches away from the first. Both of these holes should be inside the area of your access door location.
Repeat this process with the opposite floor joist.
Now slide a skewer into each hole and duct tape it into place.
4) Head back upstairs and place the fat(2") side of your square along the outside edge of 2 of the skewers (parallel to your floor joists). The 2" side of your square will overlap 1/2" with your floor joists. Do the same with your other square and skewers. If you measured correctly, your squares should form a perfect rectangle. You can adjust the length of your door to your needs, but the width is predetermined by the spacing between your floor joists.
Step 2: Cut Opening
1) It is time to cut out your opening. Using your sharp box knife, cut the carpet and padding along the outside edge of your square, leaving the carpet on the hinge side of your door intact. Only cut 3 sides! Do not rush through this step or your door may be visible after completion. Take your time and be precise.
2) Fold the carpet and padding back and cut all 4 sides of your subfloor using your circular and reciprocating saw. (the carpet will hide any imperfections in your subfloor cuts)
3) You should now be able to pull the door out of your floor completely. If not, your subfloor may be glued in place. If this is the case you will need to go back into the crawlspace, slice between the subfloor and joists with your box knife and pry it up with a crow bar.
Step 3: Prepare Opening and Door
Your door should already be the perfect size for the opening. Now you can install the 2x4 cross braces, the piano hinge, locking barrel bolt, handle(optional), and rubber seal(optional).
1) Add a 2x4 support between the floor joists at each end of your door opening. It should only extend 1/2 inch into the door opening to support the door when it is closed.
2) If you are going to install an adhesive rubber door seal, a recess needs to be cut around the underside perimeter of your door to account for the extra thickness. install the seal on your floor joists, put the door into place, and measure the difference in height to find your recess depth.
2) Install hinge. The hinge needs to be recessed so there is no visible bulge in your carpet. Line up your door in the opening and put the hinge in place, mark the outline onto the door and subfloor. Use a chisel or router to cut a recess for your hinge. reposition your door and attach the hinge. (I used a gate style hinge, but a piano hinge will be much easier and just as strong) Make sure the door is aligned with the opening properly.
4) Install barrel bolt lock and handle. Drill a hole into the side of your floor joist to accept the barrel bolt.
Step 4: Attach Carpet
1) The carpet around the perimeter of the door opening needs to be secured to the subfloor. First apply double sided carpet tape to the subfloor on all sides of the door except the hinge side. Secure the padding to this tape. Then apply tape to the top of the carpet padding in the same areas and secure the carpet to this tape.
2) The padding and carpet need to be secured to the secret door. Only apply carpet tape to the side of the door opposite the hinge. This will allow the carpet and padding to flex when the door is opened. Since I pull on the carpet to open the secret door, I decided to also use wood screws every 4 inches to secure the carpet to this side of the door. Do not screw them in too far, you don't want suck the carpet down and leave a visible indention.
3) Clean up the edge of your carpet and padding with your box knife so the door closes easily.
I installed a permanent ladder and light switch to make the space more accessible and useable.