Conventional safes work well as a way of securing your valuables, private documents, identification, or firearms within the home. Floor safes, however, add an extra level of security that normal safes cannot offer. Because they are in the floor, a floor safe is very easily hidden, and even a thief, who checks "all the usual places", such as in cupboards and wardrobes, and behind paintings, will be hard pressed to locate a floor safe, even if looking for it. Floor safes add a decent amount of fire protection too, so that even if the whole building burns down, you have a good chance of recovering the contents of your floor safe.
Hidden floor safes do require a degree of maintenance, preparation, and some precautions to be made for installation. Floor safes are normally set in a concrete floor - any other building material would make the safe somewhat ineffective - and so require some preparation. This means either retaining a cavity in your concrete slab at the time it is poured or having one excavated later. While the first option is much more preferable and ultimately cheaper it is obviously not always an option available to you. If you have a cavity made at the time of construction you will probably wish to go with a square or rectangular shaped safe. While these tend to be more expensive they are also come in much bigger sizes. If you are having a hole excavated then it is cheaper to have a circular hole drilled and fortunately, there are many safes available for just this purpose.
It is possible to buy good Major, Allied, Browning, CMI, and Sentry floor safes in this configuration to name just a few. The prices for installing floor safes varies too greatly to put a number on it here, as the cost of having the hole cut, purchasing the safe, installation, concealment, and bolting safes to the floor all vary per the location, conditions and situation at hand.
Good floor safes are designed to be fire resistant and may be rated to withstand extreme temperatures for a specified period of time without the internal temperature rising beyond about 350 degrees Fahrenheit, which means it doubles as a fire safe. Even if it is not specifically rated as being a fire safe the way floor safes are used gives them a natural advantage in fires, since they are only exposed to heat on one face - the door. This is typically the thickest side anyway and because being below ground level itself, they will never be directly heated by flames, only by radiant heat.
Any good floor safe will have a water-proof or at least water resistant, seal which is important in any situation especially during a fire. Nevertheless, it is worth your time and effort to store the contents of a floor safe in a sealed airtight bag just in case. Some floor safes will have a typical hinged lid which can be unsuitable if there is a significant gap between floor level and the top door of the safe. Some antique floor safes tended to suffer from this problem. More recently safe designers have come up with doors that can be removed completely, lifting out once unlocked. The absence of a hinge does not necessarily weaken the security of the safe, as one might think and, in some cases, the required design and engineering actually helps to make the safe more secure.
