Concrete Bottom Boards for Beehives

New Zealand Journal of Agriculture, Volume 98, Issue 3, 16 March 1959, Page 291

Concrete Bottom Boards for Beehives

By

I. W. FORSTER.

Apiary Instructor, Department of Agriculture, Oamaru

MAINTENANCE and replacement of wooden bottom boards involve beekeepers in considerable recurring expense, as they are inevitably exposed to dampness and attack by rodents, though modern preservatives have done much to reduce the effect of rot in timber. Concrete has been used from time to time, but few beekeepers have used it on a large scale. In this article the author describes a concrete bottom board which is giving such satisfaction that several beekeepers have adopted if as standard equipment.

THOUGH the bottom board is a simple, uncomplicated piece of equipment, it occupies an important and difficult position and must measure up to certain definite requirements. It must be able to support the weight of the hive with a full honey crop, which may total several hundred pounds. As this weight is precariously tiered and often top-heavy, the bottom board must not tip or sag. Its collapse at a critical time can wreck a hive which, in falling, may in turn “skittle” a whole row of hives. Because the bottom board is so constructed as to provide the hive entrance, any distortion may interfere with the free passage of bees as well as affect the ventilation of the hive. Particulars of the bottom board which is the subject of this article are as follows. pWg Of the same length and width as a standard wooden bottom board, the concrete bottom is about 1 in. thick. The convenience of being able to mould concrete easily to angles, curves, and graduations should be exploited to the full. The edges of the rim should be slightly rounded and the inner edge sloped to the floor at an obtuse angle, thus avoiding abrupt corners. The rim itself should be 1 in. high in the front, diminishing to J in. at the back. This gives the floor a slope down to the entrance to shed water and to facilitate the removal of debris by the bees, while the hive itself can stand dead level. Moulds A concrete bottom board must come from the mould even and true, as it cannot be trimmed or corrected later; therefore moulds must be of a solid construction that , will not give or warp. Wood can be used, but the continual wetting and drying inseparable from the moulding of concrete tends to cause some distortion of wooden moulds. If moulds are made from wood, they are best line with flat iron to protect the

wood from the effects of the wet concrete. The most satisfactory moulds are of iron, which can be readily cast by a foundry if the beekeeper provides the required pattern. Though they are more expensive, iron’moulds will turn out high-quality bottom boards for an indefinite period. The additional cost can be offset by several beekeepers bearing the expense, either on a share basis or by paying a hire fee to the owner. Composition of Aggregate To keep the weight to a minimum and to give greater warmth it is desirable that as much porous material as possible be used without unduly weakening the finished product. Though pumice may be suitable, coke breeze has been used with success and a satisfactory ratio to other ingredients arrived at by trial and error.

A suitable aggregate consists of 2 parts of coke breeze, 1 part of sand, and 1 part of cement. A piece of ordinary fowl netting extending the width and length of the bottom board is usually. sufficient reinforcement. Some beekeepers give additional strength by setting a piece of No. 8 wire down in the groove of the mould, running along the back and both sides. It is this groove, forming the raised rim of the bottom board that is most likely to be damaged. Though this extra reinforcement is obviously an advantage, actually many hundreds of concrete bottom boards with only wire netting for reinforcement have been in use for some years with no sign of deterioration. Making the Boards The concrete must be mixed wet enough to give a smooth surface against the mould. The coke breeze

will tend to rise and roughen that surface which will eventually be the underside of the bottom board. This roughness . roughness has no apparent ill effect m , , •<, .fl, ~ , , practice, but if it is trowelled down a , , ’ , , , short time after the concrete has been poured, the breeze will stay down and ' a smooth surface will result.

Newspaper can be used to line the moulds and thus facilitate the removal of the finished bottom boards. Such t • j , .c n j lining needs to be carefully done, as any wrinkling of the paper gives a rough surface to the upper side of the bottom board. When paper lining is used the boards may be removed from the moulds in 24 hours; otherwise, 2or 3 days must elapse before this can be done in safety. Concrete boards should be left for some months to dry thoroughly before use.

Cost In all concrete work thp availabUlty /?, aU concrete w ° rk tke availability of the material largely determines the , T r j • + cost. Under average circumstances . # , . , , , , , cost of material per board would probably be- ’ s d Wire netting for reinforce-

ment . . . . . . . . 3 Cement (12 boards from a b g at 13g 1 , o , , ”.’ ” . Sand and coke breeze (98 boards from x d at £1) 2 .t 1 gt. Some expense will be incurred for moulds, but this is not recurring. Labour must be allowed for, but this would not equal that required to assemble wooden boards and apply preservative.

Disadvantages

A change from the conventional wood naturally engenders some criticism and certain often-quoted disadvantages in concrete bottom boards do need examination.

Inability of Concrete to Take Nails

Some beekeepers object to concrete bottom boards because they cannot be nailed or stapled to the bottom box when this is necessary for shifting hives or to keep stock from sliding the hive across the bottom board. This is certainly a drawback where it is necessary to nail into the bottom board. However, the use of bottom shifting screens provides a very satisfactory way of shifting hives and allowing the bottom boards to be carried separately.

If top screening is used, the lid is then available to stand the hive in. If conditions are such that no screening is required, the hives can be stood in spare lids, on a sack, or straight on to the flat deck of a truck. While in the apiary hives are not usually nailed even to wooden bottom boards, and they do not seem to slide any more readily on concrete. Weight Concrete bottom boards, because of their extra weight, do increase the work of transporting hives. This weight factor is one that cannot be completely overcome, but it has been reduced to a minimum in the bottom board described here by using the maximum proportion of coke breeze consistent with the required strength. This concrete board weighs 26 lb. compared with 6 lb. for the lightest counterpart in wood. However, space is usually a more important consideration than weight when apiaries are being moved, and in this respect concrete does not suffer in comparison with wood. Warmth Factor It is considered by some that as concrete is colder than wood, it could be injurious to bees, but concrete boards as described here have been in use for many years in conditions colder than average with no apparent ill effects. The use of a porous material like coke breeze makes a warmer board than if straight sand or gravel was used. Advantages Advantages of concrete bottom boards are: 1. Their great strength. 2. They are everlasting, with no maintenance costs. 3. They will not burn. Beekeepers using concrete bottom boards find that they have much more freedom to control grass growth by fire. 4. They will resist attack by rodents. 5. They have no crevices to harbour disease and can easily be sterilised by scorching.