This instructable will show you how to build sliding doors for large bookcases.

I had a pair of Ikea PAX shelves that I bought a while back, and thought I would go back to Ikea to get some doors for them. The cheapest doors they had were $600!!

So... I built these myself in a weekend for about $100.

I wanted the look of a 3/4" solid door. I originally thought of doing this with Plywood or particle board or MDF, but there were three problems:
1) 3/4" boards are really heavy
2) Lower cost plywood is not very flat
3) Only the 3/4" particle board is available finished, and it is expensive for a big sheet of that... yeah you could laminate the other stuff, but it would be a pain and add some expense.

I hit upon this idea of using low-cost pre-finished tileboard on an MDF frame and hanging the doors using a sliding bypass door kit. Wasn't hard, and works great.

You will need:
- A sliding door kit. This is also known as a "bypass door" kit. I used Everbilt model 208-760
- 2 sheets of tileboard (recommend you get them cut to size at the store - follow the directions in the sliding door kit to determine the right size and don't forget to subtract the width of the trim that you will use, if you trim the doors)
- 3/4 inch plywood that is as long as your bookshelf is wide and about 16" wide
- A 4x8 sheet of 3/4" particle board, ripped into two 8'X4" strips and the rest into 8'x2" strips. Get them to rip it for you at the home store, it might cost you $0.25 a cut, but this will save you a bunch of time later.
- Edge trim for the doors - I used 3/4" pre-finished polystyrene outside corner, but you could also use iron-on melamine edging or the trim that is intended for use with the tileboard
- Crown molding for the top. I used pre-finished polystyrene again, a big labor saver.
- Loctite "Power Grab" construction adhesive (I used a whole caulking-gun sized tube)
- Finish nails (an air nailer makes the molding installation way easier)
- Long particle board screws - at least 1 1/2". I used 2 1/2 " #9s specifically designed for particleboard
- Miter box or electric miter saw. Seriously, if you have a friend with the electric saw, it is worth a 6-pack to borrow one even for a project of this size.

Hide that stuff!

Step 1: Secure the Sliding Door Track to the Top of the Shelf

This is a tall bookshelf and we're going to be adding some weight to the front, so the first step is to secure your bookshelf to the wall at the top, if it's not secured already.

The Ikea PAX shelves come with hidden brackets to do this. If you have molding at the base of the wall, you can either remove the molding, or install a 1X6 board all the way across the top, screw the board into your wall studs, and screw your shelf brackets into that board.

Do not do anything else until you have secured the top of the bookshelves to the wall per the shelf manufacturers instructions. If you do not secure the top of the bookshelves to the wall, you run the risk of the shelves toppling over causing serious injury or death.

If your installation is covering more than one bookshelf (as mine is) then secure the bookshelves together so they don't move independently of one another (PAX comes with screws for this).

Cut your plywood to the width of the bookshelves (78.5" if you are using the PAX), you may need to cut the bypass door track to size with a fine-toothed hacksaw if it's longer than the plywood.

The track requires a space between the front side of the track and the fascia (crown molding) at the front per the track manufacturer's instructions. I used one of the strips of 3/4" MDF as a temporary guide to set the track 3/4" from the front of the plywood. Pre-drill pilot holes for your screws and then screw the track in place with the 3/4" screws.

The track manufacturer's instructions assume that the area behind the doors will be open. Since we have a bookshelf there, I made a 3/4" gap between the bookshelf and the backside of the track using a strip of 3/4" MDF as a temporary guide. Now attach the plywood to the top of your bookshelf by predrilling holes into the uprights of the bookcase and using 2.5" #9 chipboard screws. I used 3 screws per upright, total 12 screws.

Step 2: Cut the Frames for the Doors

I created a frame going around all 4 edges of the tileboard with a center crossbar - yours may be different.

Lay out each door panel and create a frame for each one. Use the 3/4"x4" particleboard strip for the cross-member at the top. Use the 3/4"x2" particleboard strips for the sides (uprights) also for the center and bottom crossmembers. (cut the strips to size).

Note that in the photos, the top of the door is the side nearest the camera.

I created this so that the uprights could be screwed into the cross-members using the 2 1/2" #9 particleboard screws by pre-drilling and screwing through the upright into the cross-member. Don't install the screws yet, I would install those screws after I had all the uprights in place and the whole thing ready for gluing in the next step. The screws I used don't seem to be adding a lot to the design in mine, and mine is holding up with no problems. If you were really concerned you could try those funky screws they use in Ikea furniture.

Step 3: Glue the Frames to the Doors

Here we go... this is nail-less installation of the frame to the door.

When you have everything in position, screw the uprights into the cross-members using the 2.5" #9 particleboard screws, pre-drilling if you haven't already done so. Once you have done this, don't try to move the frame again until after you have glued everything in place and the glue has dried.

Use the Loctite Power Grab adhesive which is specifically designed for this kind of thing. Follow the instructions on the container. Don't skimp on the adhesive, you'll need lots of it. Attach the frame to the tileboard.

Repeat for the second door.

Once everything is glued up, place some heavy weights all around the frame and allow the glue to set overnight.

Step 4: Install the Doors

Wait for the glue to dry...

Install the sliding door hardware on the doors, following the manufacturer's instructions. remembering that the 4" crossmember is at the top.

Install the doors to the track according to the track manufacturer's instructions.

Step 5: Add Trim and Molding to the Top

You can get creative here... I nailed more of my 2" particleboard strips into the top of the unit, hiding the sliding door hardware (see photos). Then I attached my crown molding to that using finish nails.

Step 6: Trim the Doors. Tidy Up. Finished!

Decide your trim method for the doors. I used 3/4" pre-finished outside corner, cut to size, mitered, and glued to the door using more of the Loctite Power Grab adhesive. This leaves about 1/16" of exposed particleboard showing at the back of the door - if this bothers you, you could paint, or use iron-on melamine edging on the edges of the doors before applying the trim. I haven't done it yet, but I think I will caulk my edges with white painter's caulk and see how that looks.

The last remaining area for trim is the exposed edge of particleboard under the crown molding. I haven't done it yet, but I think I will use iron-on melamine edging for that.

Caulk the nail holes in the crown molding and you are done!!