The trend for use of natural materials in both new build and refurbishment projects is here to stay. In fact, it’s gathering pace.

In many refurbishment projects natural materials reflect the materiality of the original building and in heritage environments they provide a like-for-like reference that stays true to the period and design of the building. Meanwhile, in the new build sector, natural materials provide an impression of quality and in many cases form part of a biophilic design focus that brings the natural, outdoor world into the indoor space.

The problem for both architects and end users is that natural materials, by their nature, are never off-the-shelf perfect. Mother nature does not have an ISO-compliant quality assurance process for delivering consistent uniformity or traceable batch numbers. Natural flaws and variations are part of the beauty of natural wood and stone but there still needs to be an assurance that the material will look right and perform well. That’s why Chisholm & Winch takes a meticulous approach to working with the client, the architect and the supply chain to ensure that all natural materials used on site match both the design intent and the client’s expectations of quality and aesthetics.

Clear Parameters for Variation

The key to ensuring the natural materials installed meet the architect’s specification and the client’s requirements is to manage expectations. While clients are usually realistic about the inevitable variations in natural materials, however, one client’s version of acceptable variation may be too much of a stretch for another. Moreover, as commercial matters are usually finalised following acceptance of the bid, cost parameters are quite rigid by the time stone selection occurs, so there is little wriggle room to adjust the quality or price of materials.

It is not for the contractor to decide what should or should not be sufficiently consistent. Instead, it is part of the contractor’s responsibility to manage the procurement process in a way that engineers subjectivity out of the decision making by setting clear and measurable parameters. Often the stone type has been specified by a region and a geological type, coupled with an NBS specification that contains subjective statements such as ‘free from vents, cracks and fissures’ or ‘white background with contrasting monochrome veining’ and perceptions of what this means in reality can vary dramatically between stakeholders involved in the project

Let’s take Carrara Marble as an example. This high-quality and premium-priced material can define the look of an interior but, if there is too much variation or too many natural flaws, it may not pass muster, regardless of the calibre of the installation. If the client is not happy with the finish, replacing the ‘substandard’ materials can be a costly business and incur delays for procurement and shipping of replacements, along with removal and reinstallation.

To ensure this situation is avoided, the Chisholm & Winch team takes the architect’s specification and visits the supplier to view the material and select samples. At this point it can be immensely helpful to have a clear understanding of the particular idiosyncrasies the designer values so that this can be aligned to the best possible match within the available budget. If the supplier cannot match the required quality or aesthetic within the budget, the contractor needs to find out why. The answer is often that a particular tone is not coming through the works and, if this is the case, no amount of rejigging the budget will secure. The only option is to adjust expectations and be as pragmatic as possible.

The sample choices from a supplier visit provide a range of variation and flaws and these can then be discussed with the client and/or architect to agree the acceptable range of inconsistency permitted for the project. Once the range has been set with the client’s choice of two samples, we can negotiate a price and lead time with the supplier, with a clear understanding that only materials that fall within the range of the two chosen samples will be accepted for quality purposes. It is then the responsibility of our site team to check the materials that arrive on site against the samples to verify the materials are on spec.

This may seem time-consuming to some contractors but, at Chisholm & Winch, a right first time approach to delivering projects on site is embedded in our culture and this procurement process for natural materials minimises waste, cost and delays while underpinning quality.

Detailed Material Selection for Every Detail

We take the same detailed approach to selecting timber and veneers, actively managing the supply chain to bring clarity to the specification and consistency to quality assurance.

And it’s not only for natural materials that we take such an attention to detail approach. Establishing an agreed sample for materials ensures that the finish is on point across all elements of the interior fit-out, reducing the potential for snagging issues and contributing to on time, on budget handover. Every client should be able to expect this as part of a 360 degree approach to quality assurance.