Laurence Edwards explains how condensation on beehive roofs kills colonies in winter. Water drips onto the bee cluster and cools it dangerously. The fix is simple: add insulation board between the roof and sidewalls to stop the moisture.
This will kill your bees over winter. If your roof is less insulated than the sidewalls of your beehive, all of the condensation forms on the underside of the roof and drips directly onto the cluster of bees. This will cool the cluster down and make it really hard work for them during winter. Luckily, it's a very easy fix. Take a piece of insulation board, cut it to size, pop it into the gap, and your bees will thank you come the spring. If you don't fix it, it will kill them.
