One of the most common mistakes can be considered the lack of materials that will inevitably go on cuts and waste (what is called a technological margin). But they are always there, and their number depends on the roofing materials used and the complexity of the roofs. For example, if you put a metal tile, and the roof is complicated, you can throw up to half the material in the form of scraps. Either due to ignorance and errors, or especially in order to reduce the total cost, some companies try not to take into account this amount of material. And then their estimates are cheaper than other. But at the final stages of the roof installation, the above situation is obtained. In this case, you will have to contact this company again for the purchase of missing materials, again paying for delivery, and your final expenses begin to exceed the price of the economy class kitchen and for services from other companies that initially came out more expensive.
But sometimes even the purchase of missing building materials may be difficult: they may not be in the warehouse, and then you will have to wait for some time, or as a client you can already be uninteresting for such a company that does not want to engage in small volumes. In this case, searches can stretch for a long time. In this case, we advise you to verify the real areas and the number of roofing materials, which is present in the calculation, they should not match.