What is a Weatherboard?
A weatherboard protects the bottom of an exterior door from getting saturated by rain, and also stops rain from coming in underneath the door.
uPVC doors generally come with a weatherboard already fitted, or it may not be necessary because of the way the door and frame fit together.
Wooden doors seldom come with a weatherboard already fitted though, so it’s worth putting one on yourself.
You should be able to purchase a piece of weatherboard from your local builders’ or timber merchant – make sure you get proper door weatherboard, as it is shaped specially for the job – you can’t just use any old piece of wood!
A hardwood weatherboard will last a lot longer than softwood, but if your door is made of pine there’s not much point in fitting a hardwood weatherboard that will last longer than the door!
How to Fit a Weatherboard
Firstly, with the door closed (assuming your door opens inwards, as almost all external doors do), measure the distance between the door frame stops on the outside.
Cut a small piece off one end of the weatherboard, cutting at an angle so that the front of the weatherboard is narrower than the back. Then cut your length of weatherboard to fit the door opening width you just measured, again cutting at a slight angle. These angles ensure that the weatherboard won’t catch on the door frame as you open and close the door.
Stain or prime and undercoat the back and underneath of the board, so that it will match your door – you can do the front later when it’s fixed on.
With the door still closed, position the weatherboard against the door – it needs to be as far down as possible but not touching the sill.
Draw a line across the top of the board onto the door, so that you can find the position again later. Mark on the weatherboard where you want the screws to go, and drill and countersink holes for them – three holes are enough for a standard-sized door.
Position the weatherboard against the door again, lining it up against the line you drew earlier. Screw the board into place, and use wood filler to fill the screwholes.
Try opening the door and make sure that the weatherboard doesn't catch against the doorframe anywhere. If it does, use a plane or sandpaper on the part that catches until it doesn't touch any more.
Use filler or sealant to fill any gaps along the length of the board, so that rain can’t get down between the door and the weatherboard.
Now you can stain or paint the front of the weatherboard to match the rest of the door.