A house built on OTR tires in Canada

An example of energy efficient home from used tires. Image source: westerntirerecyclers.com

An example of energy efficient home from used tires in U.S. Image source: westerntirerecyclers.com

Peter Schroedter has been in the OTR business in Manitoba, Canada, for a long time. He told Tyre and Rubber Recycling that Manitoba had some challenging issues to deal with, not the least of which was a stock of ELT OTR tyres.

There was a problem with housing in Manitoba, the soil was a heavy clay and it was prone to absorbing water, which froze in the winter and then dried out in the summer. The constant expansion and contraction was a real problem and houses suffering from the subsidence Dr. Shokry Rashwan of Red River College explains the benefits of tyre backfill or wall deformation was a real issue across the Province.

Of course, basements are an essential part of the housing stock in much of North America, and that is true in Manitoba as it is in Texas. But if you build your basement in a clay ground you have some special problems in Manitoba. There is the aforementioned behavior of the clay itself, but all that frozen water creates an insulation issue; those basements get cold in winter – which is fine for storing fruit and veg but not so great if you want to use the basement for anything else.

Around about now readers will be thinking that buying that second home in Manitoba is maybe not a great idea. But we are not done yet. The geography in much of Manitoba means that it is a source of Radon gas, and the gas permeated foundations and vents into basements where it can collect if not vented to the atmosphere. Radon is known to cause cancer.

Now, whilst not claiming to cure cancer, Peter Schroedter and his partners at Red River College, headed up by Dr. Shokry Rashwan have come up with a potential use for OTR tyre shred that may ameliorate all three of this issues.

The norm when building a house in Manitoba is to excavate the plot and lay a layer of gravel 9 or other material under the concrete basement floor. This is suitably protected from damp, and includes groundwater sump and pump, plus a radon vent. The walls are built up to ground level, again suitably protected from damp. And the void around those walls is backfilled with gravel or perhaps even spoil from excavation. Though most builders remove the spoil from the site and ship in gravel as a backfill.

So, Schroedter hit on the idea of using tyre shred as the under floor base and backfill.

Of course, the road to get anywhere near trying this out has been blocked by more permits and paperwork that can be imagined. Tests were needed. Results were required. Hence, the Red River College involvement.

The project built a house to experiment on the use of tyre shred. They actually built a house of two halves. Between the two halves was a central dividing wall that dropped some three feet below the lowest point of the sub floor level so that there was a clear division and no seepage between two halves of the house. One side was built with a gravel sub-base and backfill, the other with tyre shred. Identical sumps, pumps, vents were fitted in both sides of the house and they waited for the results.

It was good news. The tyre half of the house was shown to have better insulation properties. It also drained rainwater quicker than on gravel, by a quite considerable volume, around 30 times more water was pumped out of the sump on the tyre side than there was on the gravel side, so the tyre backfill was drier, and there was less liability to the waterlogged backfill freezing in winter. So it was warmer, though to be fair warmth in a Manitoba winter will be a relative measurement in this experiment.

What surprised the researches, said Rashwan, was the fact that the Radon levels in the tyre sub-base half of the building were considerably lower than in the gravel sub-base. So, at this point the tyres were three up on the gravel. It was also important that the heave or subsidence was measured, after all, it isn’t much use in the building warmer and drier and less susceptible to radon if it is still falls down.

The college laced some hundred or so sensors on the floors and in the walls of the building to measure the movement. Here, early results have also shown that the tyre backfill and sub-base have reduced the heave and subsidence in the building, though the tests are ongoing.

Schroedter is very positive about this project. He said, “I’ve got a lot out of this business over the years. I am looking to retire and I would like to give something back to the community and the industry. I think this project has a huge potential in areas that share a similar geography to Manitoba. It has long been known that a layer of tyre crumb and help ameliorate the impact of ground vibration, but this takes things a step further, it allows us to build homes that will not fail, due to unavoidable climate and soil issues. I really believe that this is one solution of tyre disposal that has a relatively low cast and a remarkably high positive outcome”.

Article source: Tyre and Rubber Recycling

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