Look at how dark the wood is in this picture. Honey bees cover everything in their hive with propolis (aka bee glue) Propolis is plant rosin (tree sap). Just as it protects plants when a limb is cut off from bacteria and fungus the bees use it to prevent fungus and bacteria from hurting their hive.
Again look at how dark the inside of the wall is. This new colony did not have time to cover the interior of their new home with propolis. If you look real close you can see some of the white marks where wax moths larva had built their cocoons into the Sheetrock on the right and left side.