Limestone Wall and Arch
Limestone Wall and Arch
My grandfather was a baker in Cincinnati, Ohio in the very early 1900s. He and my grandmother owned and operated a neighborhood bakery in Clifton Heights, just 400 feet from where I was born. Once he retired, he decided to build an eight-unit apartment building just down the street from the bakery. He named it Valley View because it had a commanding view of the Mill Creek Valley. I never got to meet him as he was sent to Heaven fifteen years before I was born.
There are quite a few photos of him in the family photo albums of him standing next to limestone walls, arches, and a stone fountain he built with his own hands in the apartment building gardens. They were gorgeous and keep in mind there were no YouTube videos to watch, probably no great DIY books at the local library, or home improvement shows to watch on cable TV. Somehow, somewhere my grandfather gleaned the information to build stone walls and arches on his own. You can do it to with his inspiration and a little help from me.
Almost all stone is suitable as a building material for outdoor walls, arches, and fountains. After all, the rock most likely has withstood thousands of years of exposure before it was quarried or hand-picked from a road cut or stream bed. My grandfather used pieces of fossiliferous limestone that is abundant in Cincinnati, Ohio. Limestone is an excellent material to use. There are thousands of buildings all over the USA that use fine-grained limestone for their facades. It’s extremely durable.
Do Limestone Walls and Arches Need Footings?
Whenever you build with limestone outdoors, it’s wise to install a sturdy foundation or footing. This is true no matter what stone you use. If you live where the soil freezes, be sure the bottom of this footing is below the local frost level. The footing helps spread the load of what you’re building on the soil below. I prefer my footings to be at poured concrete at least 8 inches thick with 5/8-inch-diameter steel bars in it every 2 feet on center to ensure the footing doesn’t fall apart or bend. The footing should be no less than 2 feet wider than the wall or arch structure you’re going to build. You can discover more about how to build a footing here.
If you’re building a retaining wall that’s 4 feet high or shorter, you’ll rarely get into trouble. The issue with retaining walls is the tipping force increases at a greater rate the higher the wall goes. Any wall over 6-feet tall should be designed by a structural engineer that has a deep history of producing plans for retaining walls. You can discover the different types of retaining walls you can build out of limestone here.
How Do I Start Building With Limestone?
Laying limestone can be challenging and I suggest you build a small test structure first to get the hang of it. Be sure the stone is clean and dust-free so the Portland cement mortar will adhere well. Most stones you work with are slightly tougher to work with than brick. Brick has suction and when you lay brick, the brick absorbs the water in the mortar quite fast. This allows the mortar to get stiff within minutes.
This doesn’t always happen with stone so you often have to make the mortar mix a little drier. When working with limestone like my grandfather used, you can rest assured his mortar mix resembled mashed potatoes, not applesauce.
What Type of Mortar is Best for Limestone?
I recommend you use a strong mortar that’s one part Portland cement, three parts medium or coarse sand, and 1/2 part hydrated lime. The hydrated lime will make the mortar a little more sticky and it greatly enhances the strength of the mortar over time. All three ingredients are quite inexpensive.
If you have the time and want extra adhesion between the mortar mix and the stone, you can coat the top of each stone with cement paint just before applying the mortar mix. Most people won’t have the patience to do this. Cement paint is just a mixture of Portland cement and clear water. You blend the two so it’s the consistency of regular latex paint.
Are Limestone Arches Hard to Build?
Stone arches are not that hard to build. The Internet is littered with videos and photographs of the arch form you need to build using plywood or oriented strand board. The arch form needs to be as wide as the stones that are being used to create the arch.
What Prevents the Arch From Collapsing?
The walls that the arch sits upon need to be substantial. You can get clues, guidance, and inspiration once again from photographs of arches that are as plentiful on the Internet as opinions about current events. You need to realize that gravity is pulling on the arch and wanting to spread the vertical walls below it apart. Robust walls will resist Mother Nature’s desire to bring the walls to the ground for many many decades.
To give you an idea of how big to make the walls, you should look at the stone archway that graces the entrance to Avon Fields Golf Course in Cincinnati, Ohio. (Refer to the photo at the top of this column.) There you’ll discover a limestone decorative structure that has an arched opening that’s about 3 feet wide. The walls on either side of this opening you can walk through are just a little bit over 3 feet wide as well. This stone arch has been in place for almost 100 years with minimal maintenance and still looks magnificent.
Before you start your project, I urge you to look at hundreds of photographs of stone walls, arches, etc. to get an idea of what’s possible. Pay close attention to how the mason cut and fit the stones in the arch. I know you can do this and think of the company you’ll be in!