Any wall not built on a solid surface must have a firm and level foundation. Standard wall foundations consist of a layer of concrete on a bed of hardcore, but if the ground is particularly firm, you can get away with just a thick bed of concrete.
Whenever you are planning on doing major work on the walls of your house, you need to know if they are load-bearing or not before you start. Load-bearing walls are holding up your house, and even slight alterations to their structure can cause big problems.
Whenever you are working wood with a chisel, it is essential that you keep the blade as sharp as possible. This will not only make your job easier, but will almost always result in a better finish to whatever you are paring.
Performing minor repairs and maintenance to your roof is very possible, but you need to work safely and if possible work with a helper. Using the correct tools and equipment is an important part of working safely.