Hidden bookshelf door – Building a hidden library is easier if the wall to be used is unusually thick. However, in most cases, it is a usual 2 by 4 wall. If this wall has a room behind it, the bookshelf should be hidden in that room too. For example, if the library is 12 inches deep and protrudes into the room that shares the wall you will have to build something in that room as well. Cut an access hole in the wall where the desired hidden shelving will be built. It is better if it fits between two of the existing wooden posts. Cut two pieces of 2 by 4 to 84 inches in length. Secure one to an existing bolt on the left side of the access hole. And the other on the right side with the drywall screws.
Measure the distance from the top of the 84-inch 2 by 4 to the bottom of the existing top plate hidden bookshelf door. Subtract 3 inches and cut as many pieces as there are stiles that are going to removed. For example, if there are four studs between the two with the 84 inches 2 by 4. Then, cut four pieces to replace the studs plus two more. Place the short pieces between the two pieces cut at the end. Secure with the drywall screws. Next, remove the existing bolts from the wall and place the integrated assembly in the previous step on the 84-inch 2 by 4 and attach them to the posts on each side of it and also through the top on the plate top of the wall.
Cut two pieces of material 1 by 12-inches to 84 inches. These are the ends of the shelf. Place the ends on one of the 84 inches 2 by 4 and measure the distance between the ends and the 84-inch 2 by 4 on the other end. Next, cut as many shelves as desired for the shelving hidden to that length. Place the two ends of a work table and mark them for the hidden bookshelf door shelves. Place the square on the marks and draw lines across the width of the ends. Apply the wood glue to the ends of the shelves and secure the shelves to the ends with 1¼ inch plaster screws. Position the shelf on its front and measure the width and height. Cut a piece of plywood a quarter of an inch to those measurements.