Proportion is for free!

Or: How can project costs be reduced??

At CRAN? 2022 in Chicago, many interesting presentations in the closing podium discussion resulted in exactly this question. A question that designers and architects are confronted with almost every day! From the answers of all speakers, I found that the statement: Proportion is for free! attracted the most attention.

With this sentence in mind, it is worth taking a closer look at natural stone as a building material. Even when using natural stone as an optically dominating material for facades, floors, walls, stairs or furniture, the proportions are cost-determining. If natural stone is not used in standard sizes the project will starts with specific raw slabs. Special attention should now be paid to the stone. When choosing proportions that are too large or too disproportional for the slabs, the proportions become cost driving factors. In my projects, I experience the trend towards stone slabs that are as large as possible and thus appear homogeneous. Sizes of more than 200 x 120 centimeters for wall cladding are today considered a normal request.

Natural laws apply to natural stone in particular, which limit the quarrying of large-sized blocks. The two most important factors are the crack formation and the layer height.?

Over millions of years, tectonic movements and stress conditions have led to the fact that virtually every natural stone has a three-dimensional crack formation. Experts also refer to this as fissure structure or fissuring. This crack structure sets clear limits to the quarrying of stone blocks.?

Driven by the demand for large stone slabs, various techniques have been established in recent years to "heal" cracks in the stone.?

In principle, modern adhesives under vacuum and thermally adjusted reaction times are used to fill the cracks permanently. Depending on the stone and the process, the filled cracks even become part of the optical stone characteristic.??

The second limiting factor for natural stone is the layer height. The genesis of various types of stone was determined by a deposition layer by layer. The height was created by the whims of nature millions of years ago and is therefore an unchangeable parameter.?

Typical quarry wall -shown 3-dimensional cracks

When using natural stone, it is worth taking a look at the selected stone itself before making the tile backsplash or determining the layout of the joints.?

What should be paid attention to?

A look at the available raw slab sizes is the most economically interesting factor. But beware. There is always the lucky chance that a particularly large block can be quarried. This is all too often used as a marketing reference. In practice, these blocks are not only limited, but they also have a higher price!

Therefore, the focus should be on the average sizes of the stone slabs. And the direction of a possible veining! With this knowledge a quick check of your own planning is possible, when you ask yourself the question: how many pieces in my requested size can be cut out of the raw slab. This real usable area is also called yield. The rest is waste. If you put both numbers in relation to each other, the yield should always be greater than 60% or higher.??

Onyx - with nature given height

How to really optimize the design in terms of the stone?

The cutting of natural stone is done on large machines. Modern machines recognize the raw slab fully automatically, place the cut-to-size stone in it, and then carry out the cutting completely. On less automated machines, after the first directional cut, either the support table or the tool head is rotated and moved by the skilled worker to perform the cut in the second direction. Once a raw stone slab has been placed for cutting, it is discharged from the stock. It is not logistically or financially worthwhile to return sections. This means that, as a rule, the unused areas / sections are disposed of. In other words: simply no longer used for cutting. However, since the costs for quarrying, cutting the slab from the block, transport, surface treatment, etc. are included in these cut-off areas, the stone producer must include this portion in the costs of the cut-to-size area. In other words, the smaller the yield, the higher the cost share from waste. And it is precisely here that optimized planning can often achieve significant cost reductions in the project.?

Let's take a quick look at the waste pieces: Of course, there is always the desire to use the leftovers for another project or the production of smaller parts. However, this is often not possible due to economic, logistical, and organizational aspects. There are smaller companies that specialize in the utilization of leftovers. These are usually out of the question for a larger customized project, as they only produce small-format standard products such as 30x30 centimeter tiles.????

Optimization by the designers and architects therefore means finding a joint pattern that visually meets the design requirements and at the same time leads to the highest possible utilization of the stone slabs.??

Visualization of a project slab with the overlay of the cut-to-size used area. Optical its seems good but the real yield is at 62%!

Where is the yield visible?

In modern production processes, the capacity utilization / yield is automatically output for the block manufacturer. However, this is often not visible to the designers and architects. Also, the return of the information is simply too late for an active planning adjustment.?

In order for designers and architects to pay attention to the yield at an early stage, planning tools are required that link the stone slabs to be used in the project directly with the planning. This is exactly one of the key points of the DDL platform. By linking plans, stone slabs, designers/architects and fabricators, cost-optimizing variants can be created in parallel, in addition to focusing on the design. The time required in relation to the savings is minimal. In addition, this effort can be invoiced to the client as an extra service.

Can a homogeneous laying pattern be created in a controlled manner?

Yes, digital dry layouts can be used to create a homogeneous laying pattern without spending a lot of time. This data is then transferred to production, where it is used directly for work preparation. In addition, during production and installation, the exact implementation can also be checked and documented with minimal time expenditure. The digitization of stone slabs has become an industrial standard. The DDL planning tool is also available to all designers and architects as well as stone manufacturers and installers.

What is the smartest way to design natural stone?

Building on the architect's design idea, it is necessary to contact the considered stone installers and producers. Within the contact persons the optimization is then done based on the plans and real project requirements.?

The project experience shows that a mock-up area (plan extract from the project with a size of 20 to 50 sqm) is sufficient to identify and optimize the critical sizes. For this purpose, the mock-up surface is created in 2 or 3 variants with different joint patterns suitable for the project. The varied joint pattern should always meet the visual requirements of the design.

Through a digital 1:1 sampling over the considered companies and stone slabs, the desired appearance/homogeneity as well as the yield becomes visible. The offers per variant - based on the project reports belonging to the variants - will reflect this in their amount of costs.?

A Mock-Up section from projects plans shows not only the overall appearance of stone in real, the corresponding slab report also shows the yield

Summary:

Optimizing the proportions in the project can save up to 40% of the procurement costs in real terms, depending on the natural stone. A natural stone that is often too expensive based on the first offer should not be written off immediately and replaced by a compromise. The design goal, i.e., the material - was selected with experience and design focus. Therefore, as a first attempt, the chosen dimensions in the project should be adapted to the natural stone.?

Proportion is for free!?

Do you want to optimize your project? Feel free to contact me.