When is a Stone Not a Stone? When it’s a Mold!


One word: One, Simple, Word.

Until 50 years ago, everyone knew what you were talking about when you said your project has stone on it. It was a simple concept with no other question to ask. Today, this is not the case. When someone says they want to put stone on a project it should bring a range of questions that were never even considered in the past: Is it real or manufactured, full bed or natural thin veneer…

Today I’ll cover the first question – Is it real or fake and for that matter, why should you care. For a lot of people, that’s that’s what really matters, “why should I really care?” It’s a fair question. In the end what you want, need, and purchase is really about what is important to you.


When purchasing something, I feel it is important that the purchaser knows what they are getting. Manufactured stone is a product that is widely used, is nationally, regionally, and locally marketed, and often has the lines of truth blurred as to what it actually is. In its truest form, manufactured stone is Portland cement, maybe some fly ash so they can promote it as a green product, lightweight aggregate (gravel), and some form of coloring pigment. The basic premise is taking real stones, set them into a mold made from either rubber or plastic, and using these molds to pour the concrete into “stone” shapes. This short YouTube video gives you an understanding of the basic process. BTW – enjoy the music:)!

Here’s the areas that you should consider when selecting any stone product – total product quality, the environment, the look, and pricing.


When it comes to long-term integrity, natural stone has this one hands down. If a piece of manufactured stone is chipped it looses its pigmented color. You can also see the little pieces of aggregate and concrete. Like the picture below shows, anywhere the stone is chipped, the base of the stone is exposed. Look as well at the pieces in the middle. The center is a spot where it pulled away from the mold, and the other piece you can see air pockets where the concrete didn’t fully settle in the mold.

Then there’s natural stone. If you chip a piece of natural stone, all you see is more natural stone. Simple. No molds required, no mixing minerals and aggregates together to make concrete into something more than it really is.

A few years back I was on a sales call with a dealer in Utah. There’s a huge amount of manufactured stone in this market – residential and commercial projects almost seem out of place if they don’t have some on the building. What I found amazing though were the issues they were dealing with. Some of the developments in high end areas like Park City mandated that nothing but natural stone could be used. When I asked the salesperson about this, he stated it was because there have been so many issues with freeze and thaw that was breaking up manufactured stone. Coincidentally, the architectural firm we visited had manufactured stone on it. The sills were the typical 18 inch sills you often see made by manufactured stone companies. The sill was literally decomposing right on the building. I’m sort of a masonry nut, so I examined the installation. From what I could see there wasn’t anything sub-par on the installation. It was installed below cedar siding, and it was caulked properly, flashing in place as well. Everything looked fine – except the stone. The face of the manufactured sill was just about gone – I was literally able to take my finger and flake off pieces of the sill. It was a sad thing to see. Being a gentleman, I made sure not to bring this topic up to the architect.

Why would this happen? There are tests and standards that need to be followed, so consider a few things. First, manufactured stone testing requires the stone has at least a PSI (pounds per square inch) of 1,800. What this means is the stone will not break until there is almost a ton of pressure put on one square inch of the stone. Sure sounds impressive. Now, take into consideration natural stone standards. Indiana Limestone, which is often considered a soft stone, has a compression rate of 4,000 PSI – double the manufactured stone’s minimum requirements.

Next there’s water absorption. This is the probably the most critical for for areas that have a lot of freezing and thawing. Parts of the country where it gets warm during the day and freezes at night have a big concern with this. What happens when water freezes? It expands. So, if there is water in something that freezes, that water will expand. (Somewhat related – some old quarrying techniques used water to break large blocks of stone in the quarry. They would pour water into drill holes in winter and then cover the hole. When the water froze, it would crack the stone along the drill lines. Should give you a pretty good idea how powerful ice is). So if something has water in it and freezes and thaws over and over, it is going to affect the integrity of that material. The maximum allowable water absorption for manufactured stone is 22 percent. Again – Indiana Limestone – a softer stone – is at 7.5 percent.

Now let’s look at the average stone Buechel Stone has. For instance, our Chilton Stone has a compresive strength of 38,000 – 50,000 PSI (yes, the number of zeros is correct). The water absorption is 0.08 percent (again, correct).

What product do you think will have the greatest durability?

Manufactured Stone:            1,800 PSI      22.00 percent water absorption
Indiana Limestone:                4,000 PSI        7.50 percent water absorption
Buechel Stone – Chiton      38,000 PSI        0.08 percent water absorption


Another consideration is for those of you who get into the environmental aspect. First, there’s embodied energy (the sum of all the energy required to produce goods or services, considered as if that energy was incorporated or ’embodied’ in the product itself). The amount of energy required to make concrete, is much higher than that of natural stone. Personally, I feel this should be a bigger consideration used in LEED building. Many  building materials have a higher amount of embodied energy and the fact that distance from a manufacturing facility to the job-site often trumps this consideration seems wrong to me, but I will cover that idea another time.

Also, natural stone is completely used with no landfill growth. Stone that doesn’t fit product specifications are crushed into road aggregate, so no product is wasted.



Look at the two samples below.

Here are two options that are very similar in overall appearance  The picture on the left is a manufactured stone, the one on the right is a natural stone. One thing to consider is the picture on the left is dry-stacked (no mortar joint) and the right has a mortar joint, so it’s not a perfect comparison  Manufactured stones almost always have a more matte finish to them, where natural stone is typically more vibrant. Part of this comes from the way the colors naturally move within the stone. Whenever a manufactured stone tries to create this movement in color it comes off a little wrong. A good example of this color movements is the piece of natural stone in the upper left corner.


For many people, it all comes down to this item. Pricing is something discussed in almost every project. If you are comparing pricing for natural stone to a low end manufactured stone, it’s just not going to fall in line and there’s not much likeliness natural stone can compete. Now if you’re considering one of the high-end manufactured stones, you might be surprised how much the costs are starting to come in line with that of natural stone. Depending on the stones you are looking at, sometimes natural options can be less expensive.

When you are budgeting for your project, you many want to think about your project’s total budget. So you picked out a stone and you find out it’s a little more expensive than what was budgeted. This doesn’t have to be the end of the discussion. So often, masonry is the first place where cuts or sacrifices are made, and this often surprises me. Of course I’m going to be a bit bias on this, but think about the image you are trying to portray with your building/home/landscaping. The look of the project directly affects what people think of the quality of the building, the uniqueness design, and you as an individual. It’s also one area that will most likely outlast any other selection you make for your project. Appliances die out (seems quicker and quicker these days), flooring gets changed, furniture and office spaces get updated. Very rarely do you see someone ripping off masonry and starting over. It’s likely going to be with you for the rest of the building’s life, so why sell yourself short when you have to look at it every day? If you consider the long-term implications, you’d pick natural stone every time.

So remember, natural stone is not a commodity product. It’s as unique and individual as the people that use it and purchase it. When you make a selection and review your options, make sure to get all the facts about the products you are getting. If you are educated and make a selection for manufactured stone, that’s OK as long as you know what you are purchasing. Often, people make a selection and don’t even realize they picked out something that is actually painted concrete, not a natural stone.



Mike Buechel
V.P. of Operations and Marketing