The BCB Top Bar Hive design receives some modifications!
Building the first 2 BCB horizontal Top Bar Hives was a real journey of discovery which I thoroughly enjoyed, since finishing those hives I have made refinements to the original design. This process of evolution partly came about during the initial construction, but was also stimulated by seeing the hives in use and talking to other bee keepers.
The areas I wanted to improve upon were: the roof, roof covering, feeder and the access at the base of the hive.
The roof had ended up being very heavy and needed hinging to the hive body to make it easily opened by one person, this worked well but took extra time in the building process to fit the hinges and stays, it also meant that the whole hive needed 2 people to move it even when empty. If the roof were lighter and could be completely removed then the hive could be broken down into its component parts for transporting.
As well as making the sections of timber used to construct the roof lighter I also introduced a curve to increase the strength even though the timber thickness had been reduced to 8mm. The inside of the roof has a 1” thick ceiling of cork to provide effective insulation. These changes worked well and the roof can now easily be removed by one person.
On the Mk1 design we had opted to use galvanised steel covering for the roof as is commonly done with National hives. In the Mk2 I wanted to make the covering lighter and to give it a more natural appearance. This was achieved by fixing a canvas covering coated in varnish to make it weather tight and durable – a technique that had been widely used on the decks of boats.
I made 2 ‘frame feeders’ for the Mark1 hives, the bees in one of the hives disappeared over the space of a few hours leaving no brood behind, when we investigated and cleaned out the hive we found that the feeder was partly filled with dead bees all soaked with sugar solution feed.
We are still unsure what happened but wanted to remove the risk of it re-occurring. The most practical solution was to use a readily available plastic entrance feeder mounted through a follower board.
We introduced this modification to all the hives and they have been working very well through 2012.
A Varroa mesh floor is commonly used as part of the integrated management and monitoring of the now endemic Varroa mite this has been an essential part of our design from the beginning. In the Mk1 a ‘letter box’ slot opening was cut into the bottom of the hive through which the monitoring board could be removed, this was fine but didn’t allow for running the hive with an open mesh floor to increase ventilation.
The Mk2 has a removable base that can be used as a monitoring board for mite drop count but can also be partially or completely removed. The base is held in place with oak wedges and can be left on the supports to allow partial ventilation.
I built 3 of the Mk2 hives 2 for BCB to run and one to run myself, I am very pleased that 4 out of the 5 TBH’s that I have built to date are currently occupied by healthy colonies.
This year there are several new projects in the pipe line – I have been researching and developing the design for 2 versions of a Catenary Top Bar Hive (with a curved body replicating the shape of comb in a wild colony). I hope to have 2 of these to try out this year. Recently I have been working with Elinor on the design of an indoor natural observation TBH for an education project that BCB are going to be involved in setting up this year…..more of that later.
By Mike Southern: Bungay Community Bees