Installing baseboard / skirting board: How to cut and install skirting boards / baseboards for a perfect internal corner. Where baseboards meet at an inside / internal corner, a coped joint is used.
To find out how to make a coped joint, please watch the video. A coped internal corner is by far the best method to finish off your project. Initially you might find cutting a coped joint a little tricky, but with a little practice you will become a pro in no time. The end result is far superior to the method of just cutting a 45 degree angle (which some people tend to favour) on either end of your two pieces of baseboard. Cutting two 45 degree angles may be marginally quicker but the end result is an inferior finish. The two reasons for this is that the majority of internal corners are not a true 90 degrees which means that your two 45 degree cuts are not going to join together neatly. Secondly, when you nail your baseboards to the wall, it tends to pull the joint apart. In both cases the joint will need to be filled with filler which nearly always cracks over time leaving a poor finish.
Another renovation, remodeling tip from Uncle Knackers