Measure for the "Bee Space" in Your Beehive
Adhering to a measurement called the bee space lets you build hives that allow for the easy removal and inspection of combs and the simple separation and manipulation of the hive boxes. The bee space is simply the crawl space that bees need to pass easily between two structures (3/8 inch is the ideal space).
When the space between two surfaces in the hive is the right size (bee space), the bees will respect the space and leave it free as their passageway. But if the space between any two surfaces in a hive is much less than 3/8 inch (for example, less than 1/4 inch), the bees will quickly seal the gap with sticky propolis (a resin-like substance the bees manufacture to seal cracks and gaps in the hive).
And if the space is much larger than 3/8 inch (for example, more than 1/2 inch), the bees will fill the space with extra wax comb. Either way, violating the bee space results in a colony that you can't easily inspect and manipulate because the bees have effectively glued everything together!
You want to adhere to this bee-space concept as you build your hives (in other words, the gaps between surfaces are never more or less than 3/8 inch).
Two types of bee space exist. The 3/8 inch bee space your colony uses to move between hive bodies can be designated either at the top or bottom of each hive body:
Top bee space means the passageways between hive bodies have been designated above the frames.
Bottom bee space means the passageways between hive bodies have been designated below the frames.
Although beekeepers endlessly debate whether top or bottom bee space is better, you can't mix top space and bottom space equipment in the same hive. Top bar configuration is standard in the United States and many other countries around the world. It's even gaining favor in the UK (where bottom bee space has been traditional).
If you decide to purchase equipment from a beekeeping supply store to use with the hives you build (such as frames, hive-top feeders, and so on), be sure to confirm with the vendor that the products you're buying are compatible with top bee space.