1. the incorrect quantity of material being ordered
2. duplicate orders being placed
3. material of the wrong specification or size being ordered
4. the material supplied was of an inferior quality and couldn’t be used
Of course sometimes the surplus material is a result of the client changing drawings after the material has been procured, in which case the client should be charged for these, and they should be handed over to them.
Other causes of wastage are as a result of:
1. Material breakages due to it being damaged during transport, offloading, handling, or using the incorrect installation procedures. Sometimes some of the damage can be avoided by changing the way the material is packaged, handled or transported. For instance if material is palletised by the supplier – which could be at an additional cost – not only can the material be offloaded and handled more easily, thus reducing costs, but there will also be fewer breakages.
2. Contamination of materials which is a particular problem with concrete aggregates, or road building materials, which become contaminated when they’re mixed with other materials, or with the ground they’re dumped on. Sometimes trucks aren’t cleaned properly between products, resulting in the next product being contaminated. Occasionally goods aren’t handled correctly at the supplier and become contaminated there.
3. Products being applied incorrectly because:
a. they aren’t prepared or mixed correctly which results in the work having to be redone
b. the product may be applied too thickly – for instance concrete slabs may be formed and poured too thickly, paint and epoxy coatings applied too thickly, or joints formed too wide requiring additional sealant material
4. More product is mixed than can be used, resulting in the unused product having to be discarded.
5. Incorrect storage, which may result in materials being damaged by water, dust or heat.
6. Keeping materials beyond their shelf life which results in the material having to be discarded.
7. Poor housekeeping on a project may result in materials being mislaid or damaged by being walked or driven over.
8. Materials are supplied in standard lengths or sizes which usually have to be trimmed to fit where they’re required. Often the offcuts can’t be used elsewhere. Sometimes it's possible to order products in a different length or size which may reduce the amount of offcuts and wastage.
9. Poor quality work has to be redone.
10. Completed work isn't protected and is damaged by follow on trades, or the weather, resulting in it having to be replaced.
The additional costs to the project are not only the direct cost of the additional materials but also includes:
1. offloading, handling and storing them
2. the cost to dispose of the additional, broken or contaminated material which includes:
a. handling and loading
c. dump fees
With a little extra care a large portion of this wastage can be reduced or eliminated, especially if some thought is exercised when the construction materials are ordered. Every dollar saved in reducing material wastage is an extra dollar of profit.