Building shelves into an alcove makes efficient use of the space for storage and display and also allows you to create inexpensive, strong structures that don't require brackets or special fixings to assemble. Fixing battens around the inside of the alcove, for the shelf to sit on, is the most efficient method for creating an aesthetically pleasing shelving unit that is suitable for storage, displaying ornaments, arranging DVDs and CDs, for mounting speakers and any other application that requires robust support.
Measure the sides and back of the alcove and cut lengths of 50-by-25mm batten to fit down the sides and across the back. When cutting the side battens, take into account the width of the back batten that will be present, reducing the length by 25mm.
Drill mounting holes at regular intervals around the battens using a wood drill bit that's slightly larger than your screws, allowing the screws to comfortably pass through the batten.
Hold the back batten against the back of the alcove and place the spirit level on top to ensure it is straight. Mark the screw positions in the wall using the bradawl, and remove the back batten.
Drill the holes marked in the back of the alcove using a suitable masonry drill bit for your screws and wall plugs. Push the wall plugs fully into the holes, offer up the back batten and screw it in place.
Cut a shelf to fit your alcove from the sheet of 18mm MDF or plywood. Position the shelf in the alcove so it's supported by the batten at the back while you hold the front. Place the spirit level on top of the shelf to ensure it is level in all directions and draw around the bottom of the shelf using the pencil to mark the sides of the alcove.
Position the side battens against the wall, aligning the top with the pencil marks. Mark the side battens' screw positions in the wall using the bradawl, remove the battens and drill and plug the wall. Screw the battens to the side of the alcove.
Sit the shelf on top of the battens. If required, you can screw the shelf to the battens from above, for extra strength and security. Repeat this process for any additional shelves you want to fix to the alcove.
Measuring the opening of the alcove as well as the back is advised, so you can cut the shelf appropriately if the walls aren't entirely straight.
If you're building several shelves, measure the height of the alcove before starting, and space the shelves accordingly.
Acquiring help form another person can be beneficial, particularly when holding the shelf and marking the wall.
The mounting hole intervals will vary depending on the size of your alcove but at a minimum each batten should have a hole near either end and one in the middle. The back batten is likely to be longer and should have additional mounting holes.
Be aware of all safety precautions when using power tools or sharp instruments.