Migratory roof
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Roof for National Bee Hive
also known as an 'outer cover'
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This is shown upside down to show the inner rim. It is also
shown with no ventilation.
There are many variations to this basic form:-
Dimensions... The overall depth can be anything from
75 mm to 300 mm and many different arrangements have been
used for ventilating the space that occurs above a crown board when
the roof is in position on top of a hive. Generally the parts that
form the skirt are of 18 mm or 19 mm thickness, but
12 mm plywood can also be used. The size of the roof should be
such that there is adequate clearance between the inner faces of the
skirt and the outer faces of the hive boxes (9 mm to 13 mm
all round is adequate). The roofs that I made at APEX were
514 mm square overall and were nominally 150 mm or
255 mm deep.
The depth of the skirt will depend on your prevailing
weather. The deeper versions being much heavier and less likely to be
blown off by wind.
The corner joints may be comb jointed (and often are), but
the form of joint illustrated is less likely to allow in water for
decay.
The glue that I have used in the past was a waterproof grade
of PVA, if I were ever to make any more of this type of roof I would
try the 'no nails' type of building adhesive. I have used nails and
screws myself and find screws produce a more robust finished item.
I usually paint the woodwork with exterior grade gloss paint
which I do before the metal top skin is added.
The sheet metal protective cover is spangled galvanised and
has a thin sheet of expanded polystyrene foam (styrofoam) between it
and the plywood top skin. This helps to stop transmission of heat when
full sunlight falls on the metal top.
The inner rim is usually in the range of 30 mm to
40 mm.
One of the most common ventilation methods is shown in the
sectional sketch at right. The section has been taken through one of
the pair of 22 mm holes that can be in all four sides or just in
two opposing ones. The outer apertures are usually masked with small
pieces of '8' mesh to stop access by robber bees and wasps.
Most designs of roof are suitable for both top and bottom
bee space use. There is a
design that I developed
for top bee space use that can be adapted to normal British Standards
by adding a rim. One feature of this design is that it does away with
the need for a separate
Crown Board.
Originated... 17, 26 May 2002
