Painting a stairwell wall requires the use of a special ladder with extendable legs. There are many kinds of stairwell designs, and so planning the painting process prior to painting is required. The heights of the ladders used will depend upon the height of the stairwell. If the stairwell has a window, then painting around it will need to be taken into consideration. If the wall has a handrail, then this will need to be masked off. A mini roller can be used to paint between the wall and the rail.
Run a piece of masking tape down the edge of the stairs on the wall side. Keep the tape line straight along the risers and the treads. Run tape along the edges of the stair landing, if you have one. Leave the outer edge of the tape loose.
Unroll 12 inch masking paper along the length of the stairs and tuck it beneath the outer edge of the masking tape. Press the masking tape down to hold the paper in place.
Set up the A-frame ladder at the top of the stairwell.
Pour paint into a hand-held paint holder. Place the brush inside the holder and hang the mini roller off the side of the holder.
Climb the A-frame ladder and cut in the wall from the ceiling corner of the stairwell to the point in the ceiling corner directly above the first stair in the staircase. Paint as far as you can reach and then get down off the ladder and cut in the wall corner and above the floor or baseboard. Cutting is when you paint a straight line of paint around the wall's perimeter edges.
Set up the extension ladder on the higher steps of the staircase. Turn the ladder so that the rungs are parallel to the wall. Adjust the leg of the ladder over the lower step until both feet of the ladder rest firmly on the stairs. One leg will be short and the other will be long to make up the height difference between the steps. Lock the adjustable sliding leg of the ladder in place. Lean the ladder into the wall.
Climb the ladder and continue cutting in the corner of the wall and ceiling. Move the ladder downward until you reach the bottom of the stairs and the entire upper ceiling corner has been cut in. If the stairwell has two sets of stairs separated by a stair landing, use the A-frame ladder on the landing to cut in the wall adjoining corner.
Take down the ladders.
Go to the top of the staircase and cut in the wall edge along the steps. Paint a straight line with the brush across the wall above the stair treads and down along the stair risers until reaching the bottom of the stairwell. The border around the wall should be 3-4 inches wide from the corners out onto the wall. Feather this paint border with the mini roller to eliminate all brush marks.
Pour paint into a 5-gallon bucket and hang a paint roller screen from the inner lip of the bucket.
Slip the roller nap over the spindle of the paint roller frame and screw the extension pole into the frame's handle.
Dip the roller into the paint in the bucket up and down until the nap fibres are loaded with paint.
Go to the top of the stairwell and paint the wall in up and down zigzag strokes with the roller. Apply even pressure on the wall surface to avoid creating roller lines. Extend the extension pole to paint the higher areas of the stairwell wall. Roll the paint into the previously painted border from top to bottom until the wall has been completely painted.
Remove the masking tape and paper an hour after painting. Clean the painting tools.
Clean up any splattered paint as soon as it's noticed, using a wet wash cloth.
Ask someone to hold the extension and the A-frame ladder while working on it. Follow the manufacturer's instructions when using the extension ladder to avoid damage or injury. Do not lean a ladder against a window if the wall has a window in it.