The things required are only the basics and radios as well as other items should also be taken along, however, the first step to building an emergency shelter is to hire a contractor. This is because it is best to build shelters underground and going underground means a lot of digging.
Once the required area has been dug up you may begin laying the foundation and the walls. Make sure to use concrete as it is the most solid of all the mainstream building materials. Remember the story of the three little pigs? Exactly, the same concept here. Nothing like concrete or bricks and mortar.
Installing an air ventilation system with a filter and a supply of running water, from an underground well or stream is also advised. This can be connected to the main house as well.
Once the structure has been built you may begin stocking it. Space is at a premium here so make sure that every inch of it is utilised to the maximum. Food and water are the most important. Followed by other survival gear. Finally add some basic comforts such as a bed or an mp3 player.
When all of these are built and everything is set up, it would be wise to install some kind of security system so that it remains secure in case of a security issue. In either case, stock up on some weapons and ammunition as well. However, be sure to keep these things under lock and key and do not allow other access to your things.