Click the image above for a larger view.

Biltmore Forest Stonework: Before and After

This pair of images show how this stonework project evolved. The boulders were already in place, but ineffective at slowing erosion on the bank above. Mulch and leaves were constantly washing into the driveway. We decided for aesthetic and cost-savings reasons to leave the largest boulders and build our retaining walls to meet them. Smaller boulders were removed to make way for the retaining walls.

Stonework Project Getting Started

This image shows the calm before the storm. There’s about 9,000 pounds of stone there, (more than we need, but there are other projects planned we will use the excess for.) This is a drystone wall. Note the black geo-textile drainage fabric laid over the exposed bank. This fabric allows water to pass through, but captures silt and other fine particles that would wash through the wall. Drystone retaining walls are more beautiful and more durable than a mortared wall installed in the same situation. In effect, the whole wall is a drain, allowing rainwater runoff to pass through. Hydrostatic pressure never builds up. Hydrostatic pressure is a powerful force and is responsible for pushing over so many of the older, mortared retaining walls that we see around Asheville.

This image shows us making progress on the lower wall. The string line is level across, though the wall shrinks and grows as the driveway rises and falls.

Stonework Project Details

We used a metamorphic stone called gneiss, quarried in Fletcher, North Carolina. It’s a native stone and looks just right used for landscaping walls like this one. All of the stone is laid in its bedded plane, meaning the stones are set laying the same way they were formed. Face bedding (standing up) a stone like this can result in major problems, as water can work its way into the stone and cause layers to delaminate and peel away.

In the background you can see a rough old wall, a jumble of stones really, that will someday soon be replaced with a wall like this one.

Colorful Cobblestones

The cobblestones are very diverse; I’ve found at least three distinct types of granite. They have all weathered differently and some are quite smooth from years of use as roads. Since there was a limited supply, I split most of them in half lengthwise. This effectively doubled my stone supply and added colors to the palette. While the top might be a granite grey, or green with algae, the bottom may be brown or orange, depending on the type of soil it has been sitting in for the last few decades. Once split, the inside of the stone also became a usable surface, always much brighter and sparkly than the weathered outside. A couple of the stones actually have old paint on them, from their days as roadways. As a result the cobblestone patio is quite colorful.

Cutting Cobblestones

I have tried every different way I know to cut stone and have found the most efficient and neatest way to split the cobbles is using a type of chisel called a hand tracer. I scribe a line all the way around and around the cobble until it splits in two. The grain of granite is ideal for this type of technique; it’s very hard, dense stone, but it responds predictably to the chisel’s persuasion. The local metamorphic stones are less cooperative. I start out lightly, making sure the line is fairly straight and well established before I really lay into the stone. Once I get going, I can hear the stone starting to split, and I ease up, paying more attention to the places where it still sounds solid. A sharp chisel is a huge asset and I have been bringing the hand tracer home every night for a run over the bench grinder.

Cutting A Stone Circle

I used the hand tracer to remove large chunks of the center stone, a circle cut from a another salvaged piece of granite. I didn’t have a compass large enough to draw a circle on the stone, so I made one with roofing felt, a nail and some soapstone. I traced the circle on a piece of roofing felt and then laid that template over the stone.

Once I had the basic shape of the circle cut, I switched to my smaller, sharper chisels, which give me more control, to hone a more accurate shape. Though the patio needs one more ring to be completed, I dropped the circle stone in the center on Friday afternoon, to check the fit. The whole cobblestone patio makes me think of a flower.

Dry Stone Paths & Steps

This dry stone pathway connects the homeowner’s driveway with their favorite hangout spot, on their back deck. A single slab of sandstone provides an easy step up to the deck. The regular shape of the slab lends an air of formality to the entrance, sometimes used by guests. This serves as a counterpoint to the more natural looking stones that make up the adjacent steps, walls, water feature and bench.

The bench is found at the bottom of the water feature. It is very organic, a natural slab with a patina of lichen. The area is fairly shady and so I am hopeful that the lichen will survive. Two rugged boulders were topped and anchored in concrete to provide the bench supports.

Water Feature Before and After

This pair of images shows how we transformed this unused space. The drystone retaining wall at the bottom raised the overall grade. This allowed us to hide drainage pipes running from the house’s many downspouts. We used heavy duty solid white PVC pipe to extend the drain pipes. Though more expensive, these pipes have never failed me. Everytime I have dug up a black corrugated drain pipe it is either collapsed, perforated or clogged. Or all three. Next spring, once the plants have been chosen and given time to establish themselves, this will be a lovely view.
Click on the image above for a larger view of the water view and overall design.

Coming soon: more pictures of the water feature itself.

The Slippery Rock Gazette has published a story about “The Hiker” Memorial Mosaic in their print and on-line editions. Check it out!

This is a conceptual sketch of Salmon Falls, a mosaic water feature I’d like to build someday. Water sheets down into a recessed pool at the bottom, allowing people to approach and touch the stone. The stone will be a mixture of textures, rough quarried surfaces as well as honed and highly polished finishes. I imagine the salmon themselves to be sculpted in such a way that they are raised from the flat plane of the wall.

Really, this would work just as well as a dry mosaic, without the added element of water, which would reduce installation costs, maintenance costs and allow more interaction.

A couple of years ago I made a similar koi mosaic that lays flat as a patio.

I am frequently asked to remedy concrete walkways. Sometimes these concrete paths are old and broken down, in other cases, they just aren’t the look the homeowner desires. In most situations, the existing walkway, broken down or not, needs to be removed. This can be expensive and bad for the environment, if a good use can’t be found for the broken concrete. Whenever possible, I try to leave the concrete where it lays and place my stone over it. Dry laid flagstone is stronger and more durable than mortared paving, and it doesn’t matter how messed up the concrete is underneath it. (Mortared flagstone should only be applied to solid slab in good condition.) Laying drystone flagstone over ugly concrete saves money, and avoids filling the landfill with concrete waste. There are two main issues that can come up when taking this approach that we’ll explore below: clearance and drainage.

BEFORE: This little used path wrapped around the back of a lovely Asheville home. The homeowners wanted to pretty it up and maintain access to their backyard.

AFTER: A loose stone pathway winds its way through a field of pea gravel. Instead of removing all the concrete, I placed my flagstone over the top. Stucco became a quick fix for this ugly wall. You might see that it’s being pushed over by the bank behind it. Someday we’ll replace it with drystone!

Dealing With Drainage & Your Stone Pathway

Drystone paths and patios allow water to run over them and percolate through. This prevents pooling and reduces slick spots on the walking surface. It’s important that the top surface of the stone pathway be able to slope gently away from houses, foundations or other areas sensitive to moisture build-up or erosion. It’s equally important that the substrate below the flagstone is also pitched in the proper direction, as some moisture will pass through. This means, when I go over a concrete walkway with stone, I have to be sure the slab is draining in the right direction. This is easily assessed with a level and tape measure. A host of solutions can be considered if the drainage situation isn’t ideal.

Clearance Issues For Flagstone & Steps

Clearance issues are usually the deal breaker for whether a dry stone surface can be laid over concrete. The height of existing thresholds, curbs or steps must be taken into account at all points along the flagstone surface. The risks being that one could create weird little steps, make a trip hazard, or block a door so that it no longer opens! As it happens, so much settling occurs in Asheville homes, old and new, that I can often find the clearance I need, sometimes by replacing awkward and uneven steps with stone stairs that are uniform and solid.

In the image above, the large stone slab that acts as a step was the key to getting the clearance needed to build the path that circled the house. Previously there had been an awkward three inch rise- too tall for a threshold, but not tall enough to be a step. This stone step, at six inches tall, is a real step, consistent with those at the street and that lead into the house.

BEFORE: A broken down set of uneven concrete steps lead to the street. There’s a fourth step hidden in the shadow of the telephone pole. The top step is coming apart and is off center with the steps below it.

AFTER: I had to tear out the bottom three steps, but that was the only concrete removed for the whole project. (Reclaimed by a friend who needs clean fill for another project.) I set the steps further back from the road and gave them a consistent rise over run. I rebuilt the wall, opening the main entryway and making it more welcoming. The steps are now aligned with the path. The steps and wall repairs are mortared; everything else is laid dry.

The homeowners are both craftspeople- he’s a woodworker and she’s a potter. As we stuccoed this old block wall, we embedded ceramic tiles made by the potter. This is a picture of my favorite, a relief print made from a gravestone carving she found at Riverside Cemetery.

Contact Hammerhead Stoneworks for all you patio and fire pit design and construction needs.

Corey Mason of Clyde Oak, a design, build landscape company in Raleigh North Carolina, featured me and my work on his blog. Thanks Corey!