Calculating the cost of natural stone for a project can be very problematic; many factors effect the final cost and understanding them will help you manage your project budget and the expectations of your client. Many people have the misconception that the cost of supplying and installing stone is all calculated in the same manner, this is not the case. There are many factors to be considered from the type of material, the quality required, and the size of slabs.
Below is an indication of how the cost for natural stone is calculated.
The general reason for the higher initial cost of natural stone is when a material is rare or more difficult to quarry; a good example of this is Calacatta Oro and Carrara Bianco, both marbles quarried in similar regions, however the Calacatta Oro is in less supply and because of the position of the quarry is more difficult to extract; this raises the initial cost of the material. Both of these materials have varying qualities within the production and the higher cleaner quality with a whiter background is also more expensive because there is less of it available.
All types of materials have different qualities, this is identified at the time of production and depends on what proportion of the block of raw material is made up of first quality, standard quality or commercial quality. As a rule of thumb the higher the quality of material the more expensive it, this is because a block is made up of approximately 20% first quality, 30% standard quality and the remainder is commercial quality. When this material is made into slabs and tiles the price will reflect the quality. Sometimes a quality will be reflected in a consistent background colour as in Carrara Bianco ‘C’ and other times in the beauty of the veining as in Calacatta Oro.
When producing cut to size pieces, a continuous supply of similar quality material is needed. The quantity of slabs required depends on the sizes of the pieces to be cut, larger pieces will generally require a whole slab to produce one piece, where as many smaller pieces can be also be cut from one whole slab. The large pieces will have a higher percentage of wastage which is then added to the cost of the production. This will increase the overall price of the job. For this reason the initial slab material price cannot be used as a definite final m2 price for your job.
This type of work can become very costly, as there is generally a high degree of wastage when producing the cut to size pieces. The finished effect can be stunning and nothing can quite match the beauty of two book matched slabs as a feature wall. The selection of book matched slabs can sometimes be time consuming as the natural characteristics of the slabs can not be predicted and to source the right material to give the look required often needs a lot of patience. The final cost for the exact slabs required maybe higher than a standard slab because the more beautiful slabs have a higher value.