Recycled Clay Roof Tiles

Timeless Beauty of Clay Roof Tiles

Over the past few weeks, we’ve looked at several different examples of slate roofs and materials used at turrets. Here in Washington DC, the vast majority of roofs are made and built with flat roofing materials. Flat roofing materials are very specific, and not often or commonly found in the sleepy, sprawling suburbs in the counties that surround Washington, DC.

The vast majority of flat roofs, particularly on residential buildings use what is considered a commercial product.  In most other places in the world, these products only flat roofing systems, are just mostly used on commercial buildings. However DC is different and concentrated right here in and in a the few old cities on the east coast of the United states, commercial roofing systems are used on thousands of residential buildings.

Although, the vast majority of Washington DC is built with flat roof buildings, it’s not the only material used, throughout the city. Once in awhile, particularly at historic rowhome mansard roots, clay tile roofing will be used. Clay tile roofing looks very specifically unique and beautiful. Recently, we got a chance to look at a salvage collection of clay tile roofing that is planned for future reuse. The materials are set aside, yet to be culled and sorted. You can see these materials in the picture below.  (You may notice there are examples of concrete tile also mixed in together with the clay roof materials, and we’ll talk more about that in this coming week.)

Recycled Clay Roof Tiles

And although the majority of these materials are made with clay and we generally refer to this type of roofing as having a clay base materials, there happens to be a handful of examples of concrete or cement based roofing tiles set into the stockpile of this salvage operation.  For this type of roofing, other materials can also be used such as relatively thin metals that are made to resemble or look like the authentic earthen materials. Roofing tiles made with authentic clay substrate materials are generally fired, like a brick or ceramic tile, in a kiln at very high temperatures.  This type of roofing is often referred to as Mission tile or Barrel tile.

these materials are made with clay

These tiles work together in an interlocking, sequentially concentric type of way where each alternating tile is set in a convex and concave type layout from side to side. It might not be obvious from the outset, but although these tiles are particularly long-lasting and create a very dependable type roof system, they also require a significant amount of additional roof framing.

They’re simply very heavy and need to have a robust framing support system installed underneath of the roofing materials themselves. Typical asphalt shingle roofs, in contrast, can often be built on top of a simple sheathing set on a wood rafter or truss system set at intervals for spacing of 16 in or more. In some cases 19+” spacing can be used to support a plywood oriented strand board type sheathing which then supports the shingles.

This type of substrate framing system is very lightweight and doesn’t use a lot of materials which makes it less expensive, overall. By comparison a framing system for clay tile roofing materials, like this, must be much more significantly robust. The framing has to support a much heavier load and in some cases additional framing materials need to be set at intervals that match the center width of alternating rows of tile to support the concave layout.

The picture below shows the roof tiles just set on the ground to mimic or represent the type of spacing and layout in the configuration that would be installed on the actual rooftop. Here, you get a sense of material coverage. In a salvage operation like this, it’s important to understand how each different type of material will be calculated to quantify as it fulfills application in the field.

Those calculations are important so that it can be verified that materials are available insufficient quantity to cover the amount needed for the particular job. In salvage operations like this, the materials that are available are generally unique, in that, if the amount available or on hand does not cover the amount of space needed for the application or project, the entirety of the particular material might be unusable.

In other words, if there is not enough material to cover the entirety of a portion of a project for the entirety of a project, the material might need to be substituted or changed altogether because you can’t necessarily fill in or use a alternative type of material to finish the job as it won’t visually match.

the roof tiles just set on the ground to mimic

With this type of historic handmade material, we are calculating that the coverage area, based on extrapolation from the mock-up layouts shown here, is approximately 200 tile pieces per roofing square. That means that roughly two pieces are required to cover each square foot of the roofing surface. In a 500 ft roof, 1000 using pieces would be needed, for example.

historic handmade material

When people talk about recycled and upcycled materials, the different words can actually kind of mean the same thing but sometimes the same words can actually mean different things. Of course this sounds complicated and confusing, but we will give some examples here.

When people talk about recycled materials. Sometimes they’re literally talking about taking the materials and breaking them up into their root components and then recasting those materials or remelting them into new materials. Sometimes they’re also talking about something a little bit more like upcycling but just reusing old materials in a new application. Sometimes materials can be removed and then reused in the same application. Many construction specifications are written to require only new materials to be used in their building or renovation projects.

That isn’t always the “greenest” approach, though. Sometimes it actually makes sense to take a long-life high-durability product and reuse it in a new application. When you look closely at these pictures here, you can see that several of the salvaged roofing tiles actually have cracks and or splits and other types of damage. These products can last for many decades, but they do not withstand the test of time perfectly and they must be culled and carefully checked in salvage and reuse applications.  (Culling is basically like filtering.)

At the start of the article series, we really were talking about the use and firing and production of clay tile. Clay tile comes straight from earthen materials. However many of these tiles here are actually made of concrete. They actually came off of the same roof and we’re not certain that they were all brand new at the time of installation on that previous building.

these tiles here are actually made of concrete

For some of these are tiles, this could be their third chance at a new life.  That’s a lot of salvaging and reuse.  The picture below shows one of the concrete roof tiles which must be culled and filtered and removed from the pile as it is already broken and can no longer be reused.

the concrete roof tiles

We recommend every building owner in DC who values the longevity of their roof (and their investments) and building use a contractor who values the simple and important principles of proper roof construction like Dupont Roofing DC. Learn more about our company and the proper techniques of working with roofing on historic buildings in Washington DC here on our blog at DupontRoofingDC.com, and you can call us at (202) 840-8698 and email us at dupontroofingdc@gmail.com.  We are happy to help and at least talk through options.

On Key

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