The most common problem with curtain rods is their attachment to the wall. In older homes, where perhaps dozens of people have hung brackets near the windows, the plaster may be completely destroyed. In newer homes, the homeowner is likely to hit voids behind the plasterboard and this makes securing heavier curtains or window treatments difficult. One way to overcome these issues is to install a bracket board across the top of the window. This will allow you to attach your brackets directly into wood.
Mark the wall where you want to install your curtain brackets. This will be above the window, but the width may vary depending on how you want your curtains to hang. Measure the width of the window or window trim plus the distance to each side to the location of the marks.
Cut a 2.5 by 7.5 cm (1 by 3 inch) board to this length. Move a stud finder across the top of the window and mark the location of the studs. Align the bottom of the board with the top of the window opening or trim. Center the board so that it overhangs each side equally, and make a mark to make the board easy to align later.
Apply a serpentine bead of builder's adhesive to the back of the board. Align the board to the alignment marks you made earlier. Screw the board into the wall studs and recess the screw heads.
Apply paintable caulk around the sides of the board and fill the screw holes with wood fill. Allow the glue to dry for 24 hours. Sand off any residue around the screw holes and prime and paint the boards to match your wall or trim. After the paint has dried, install your curtain rod brackets directly into your new wood. The rods and curtains should disguise the board.
Use curtain scarves or swags or a cornice-type valance to disguise your mounting board completely. This will give you secure curtains against even vigorous children or animals that climb.