The History of Concrete and Our House Foundation ?

The History of Concrete and Our House Foundation ?

The post below was sent as an issue of my newsletter, Ready for Rain.

Rocks, Sand, Lime, and Water

Living on an island is a constant reminder that almost everything here had to be brought to the island in some form and usually on a boat. The vast majority of the houses, for example, were made from materials from the mainland. Steel beams, lumber, and appliances all arrived here on ferries and barges. It’s kind of incredible.

Thankfully one of the heaviest and most used materials is made right on the island: concrete. And lately, we have seen our share of concrete trucks and pumps as the foundation of our house has finally taken shape. Starting the construction process, I knew very little about it and now, I think concrete is fascinating.

On the podcast 99% Invisible, a guest appeared recently, named Vance Beiser, who had written a book about one of the main ingredients in concrete: sand. The book is called The World in a Grain and he shared a few of its stories in the show.

Concrete goes back to Roman times, or perhaps before. People somehow figured out that heating limestone creates lime, which could be mixed with water to create cement that hardened like rock. When mixed with gravel and sand, it formed concrete. This discovery meant Romans could build structures like aqueducts and multistory buildings. Today, these are still the basic ingredients of concrete.

But then, the Roman Empire fell and concrete seemed to be forgotten. The invention was lost for the next 1,500 years. What brought it roaring back was the great San Francisco fire.

Ernest Ransome, in the mid-1800s, figured out that you could add rebar to concrete to create a very strong and fireproof building material. He built a few buildings around San Francisco with reinforced concrete, but the idea never caught on. Then, the city burned to the ground in 1851 and guess what was left standing? Ransome’s concrete buildings. From that point on, concrete became the building material of the future.

Here on Orcas Island, we have no shortage of gravel and I’ve heard that our concrete company has its own source of sand. What must come from the mainland is lime, which is ironic, as lime has played a significant role in the history of the San Juan Islands.

After the San Francisco fire sparked more demand for concrete, limestone was discovered in the San Juan Islands and local entrepreneurs went to work. Fortuitously, the limestone was often found near the shore, which made it easy to load the processed lime onto boats for shipment to the mainland.

Like today, the process of creating lime and cement is energy-intensive and involves heating limestone up to 2000(f). To do this, they built lime kilns fueled with wood that burned 24 hours a day. For a while, the San Juan Islands were the biggest producer of lime in the state.

A refurbished lime kiln. Photo: WA State Parks
A refurbished lime kiln. Photo: WA State Parks

But there was a problem. If lime comes into contact with water, it becomes highly combustible and can cause fires. And once lime combusts, it can’t be put out with water. Like a grease fire, it must be smothered. This meant every boat leaving the islands full of lime was taking a risk and some didn’t make the journey. It didn’t take long for mainland customers to find safer and more affordable sources of lime.

Today, for our house, concrete is an essential part of the foundation and one we’ve tried to minimize. Our original plan was to have an unfinished basement with concrete walls. Being on a slope meant that, in places, that wall was over 15 feet high. That design required a LOT of concrete.

The original plan: concrete walls
The original plan: concrete walls

When we redesigned the house to be more affordable, one of our goals was to reduce the concrete significantly and the idea of a basement was the first to go. Instead of concrete walls, we would support the house on steel posts. These posts would rest on concrete footings but require only a fraction of the amount. Thanks to the redesign, we cut our use of concrete by about half. So yay for that.

The new design - posts instead of concrete walls

With all the forms in place and inspected, we could finally pour concrete and watching it all happen felt like the house was finally taking shape. A giant truck arrived on the property that pumped concrete through a tube that a team maneuvered around the property to fill each form. The pump truck stayed in place as a succession of concrete trucks kept it full. Rocks, sand, water, and cement. 

pump truck

The work happened in two phases. First, the footings were poured to create the house’s foundation. This is the where concrete touches the ground.

house’s foundation

Then, more forms were applied to create the stem walls. These are the short walls and posts, built on top of the footings, that the house actually rests upon.

footings 1

footings 2

footings 3

footings 4

The day the team pried-away the wooden boxes to reveal perfectly formed concrete walls was like Christmas. The stem walls were all at exactly the same height. More than ever before, the house was out of the ground. I could stand on a concrete wall, look out at the view and experience it at 272 feet above sea level, the elevation at which we’ll live.

concrete walls 1

concrete walls 2

Walking around the property, I continued to marvel at the size of the concrete footings, which would soon be attached to steel posts and frames. This house isn’t going anywhere.

concrete walls

In the midst of all the big, heavy and messy work, I noticed a small detail. Kelly’s concrete team took the time to add little bevels to the edges of the footings. While 95% of the concrete will be buried, the top 5% will be visible and the bevels make them look more finished.

concrete walls 4

This is the kind of small detail that matters and makes me appreciate working with professionals. I didn’t ask for that feature or expect it. But now, that concrete is more beautiful to me than I expected.

We’re entering a phase of the project where craftsmanship and attention to detail will be more obvious and important. In my experience, the houses that look and feel the best have an undefinable quality about them. Sure, they may have a great layout and beautiful finishes. They may have a nice location. But the subtle quality that makes the difference comes down to working with builders who take pride in their work.

YouTube Highlight: Flying Over the Project

Flyover of the Project and Water View