Gravel In The Garden

I have no idea what type of stone this antique English millstone was carved from, but I can attest to the fact that our skid steer could barely lift it. I averted my eyes when I saw the front tires of our loader leave the ground. Stone is incredibly dense, and heavy. If this millstone is granite, you can be sure that the carving process for this solid mass of stone was lengthy and exhausting. Stone is a treasured material in the landscape, as it is a natural material that takes just about forever to degrade. Its surfaces age beautifully. Crushed stone, including crushed granite, is a material much easier to handle and place, and is commonly known as gravel. These small shards of stone have endless applications in the garden, not the least of which involve the base and the top layer for a driveway. A giant granite millstone takes a machine and many people to move. Crushed granite can be dumped and  shoveled around wherever you need a hard surface. We have been shoveling.

Our decomposed granite display space and driveway is 24 years old. It has been subject to all manner of insults over the years, not the least of which is a near daily dose of heavy trucks going in and out. Add to that dirt spills from countless container plantings. Our graveled spaces were due for replacement.  How so? Decomposed granite comes with fines. As in granite dust. Those fines help to interlock the very small shards of granite, and harden up the surface.  But over the years, the foot and vehicular traffic drive the small granite pieces down, and bring up the soil and fines from underneath. Our gravel had become a dust fest on dry days, and a mud fest on wet ones.  It was time to replace it. As in dig out the old soil and sand contaminated gravel, and replace it with new stone.

The linden trees adjacent to the building are 24 years old. There would be roots to respect. Buried under our degraded gravel were the electrical lines for the lighting in the trees. This meant that all of the old gravel had to be loosened and dug out by hand, one pick axe and flat shovel full at a time. This was a big job, requiring both of my crews. The photograph above clearly illustrates the new gravel, some 4 inches deep, on the right, and the degraded gravel driveway on the left due for excavation and some new stone.

Our original driveway, circa 1995, was concrete. We removed all of that, save a two track of concrete to the rear. We eventually removed all of the rest of that concrete, and replaced it with a large scale crushed granite. Those large stones proved difficult to navigate, even in sneakers. They made leveling a pot on a pedestal time consuming. Big rocks are not so easy to navigate or manipulate. Little rock is much more forgiving. Our next go around, we switched to decomposed granite, 3/8ths of an inch and down with fines.  This gravel looked like sand when it went down. This miniature gravel with fines put up with our traffic for a good many years. As usual, the more moderate decision – an in between sized crushed stone –  would have been better choice.  Not too large, and not too small. The 3/8 inch and down granite gravel eventually succumbed to our traffic. I am happy to say, we are getting our chance at installing a granite gravel of moderate size this week.

I have known for a long time that our gravel needed to be taken up, and replaced. Late last week a decision was made to go ahead. We are in between jobs. The weather has cooled off. It was time to jump on this project. I am so pleased with the first signs of the results. Though it has taken lots of work to remove every object from the surface to be redone, putting it all back together has been a pleasure. Luckily, we have a home for that dirt laden gravel at our landscape yard. So we excavate and stockpile the old gravel out front, unload and install the new gravel, pick up the old and dump it at our yard-on our way for the next load of fresh gravel. How do we know when it is level? It is our best guess. Based on many years of experience engineering flat spaces. We’ll know we are close to dead on when the driveway drains properly. The mini gravel had become so compacted that water sat on top.  It took hours to trickle water the trees. It is worth it to breach that compacted layer, so water readily gets to the tree roots.

Everything in the landscape needs refreshing. Perennials need dividing. Shrubs need pruning. Soil needs a routine shot of compost. The work of the landscape is never really done. A landscape or garden is either going backward, or going forward. There is no neutral in a garden.  Fortunately a job of this magnitude only comes around once in a blue moon, but the transformation is satisfying.

I would guess we have a week left for the finish.  We excavate down to the original base layer. On this side of the drive, the lion’s share of the gravel exchange is done by machine.  But all of the spreading and grading is done by hand.

The center portion of the driveway will be done last. It is hard to spot in this picture, but the crown of the drive is too high. That crown never gets driven over. Water now drains towards the front door. In a very heavy and fast paced rain, water goes under the door and inside. A new permeable gravel driveway will correct that problem.

The new gravel at the shop has a fresh and pleasing texture. It is too big to be tracked inside. It will take a while to interlock and compact, but the crushed granite will eventually provide a stable walking and placement surface. Thinking some gravel will do for a drive, terrace or walkway?  My advice is to evaluate the size of the stone that would be appropriate for your project.

This gravel driveway has a base layer of 21AA crushed limestone, and a 3″ top layer of the same medium crushed granite we are using at the shop. The drive is a firm surface that shows no evidence of vehicular traffic, yet is is permeable to rain.

gravel driveway

exposed aggregate concrete drive with graveled edges

For those who would rather not deal with the maintenance of gravel, an exposed aggregate concrete surface provides the look of without the maintenance required of a paving material that moves. Aggregate concrete is a several part process that requires a highly skilled installation.

This driveway was beautifully done, and should provide many years of maintenance free service.

gravel terrace with exposed aggregate detail

decomposed granite terrace contained by aluminum edger strip

flagstone walkway with decomposed granite joints

concrete paver squares set in decomposed granite

limestone pavers with medium crushed granite

dramatic, the difference. Interested further in rock sizes?  The link below has pictures and descriptions.

stone and gravel sizes

 

A New Gravel Driveway

landscape under construction (8)I admire people who buy old homes, and sign up for all that it will take to renovate them. That is a huge commitment in every regard. An undertaking such as this demands lots of time and even more patience. I cannot imagine the expense. This gorgeous English Tudor style home is 95 years old. Very old homes like this one are remarkably sturdy and well built. I own a house built in 1930, and I can attest to how rock solid it is. I can barely drill a hole in my steel mesh reinforced plaster to hang a picture. That plaster and brick set over concrete block walls means that my house is incredibly quiet and structurally sound. This home features a virtually indestructible brick fired from a clay body featuring a big mineral content – manufactured with the idea of longevity and service in mind.  A good bit of the trim is hand carved limestone, all of which is excellent condition. The new roof is slate; slate roofs last just about forever. But great age exacts a toll on the working parts of an old house. Every house is a small city. It needs electricity, heat, air conditioning, weather tight windows, plumbing – this is a short and not comprehensive list. What got updated here is just about everything, and took a year and a half to accomplish. A kitchen and bathrooms that worked well in 1920 were reworked from the ground up. The interior renovation of this house is finished, and is finished beautifully.

a new driveway (1)My client’s interior designers introduced me to them and their property.  Eventually they would turn their efforts towards the landscape. Last year’s landscape efforts were concentrated on a pool, terracing, a spa, and an astonishing pergola built and installed by the Branch Studio. Screening trees, and a large collection of small spring flowering bulbs got planted late in the fall. This year, we hope to plant the front, side, and rear yard landscape. The property had been neglected for decades. The gravel driveway, all but invisible under a thatch of compost and weeds, was lined in concrete curbing that went 24 inches below grade.  A number of trees grew up, and spent decades thriving. Many of those trees were now were in serious decline.  Disease and fierce weather had taken their toll. The roots had grown over the curb, reducing the width of the drive to just over 8 feet.  A new driveway design and installation would need be the first part of the installation of the landscape.

a new driveway (13)Once the front yard landscape was agreed upon, there was a lot of work to do. Once the dying and diseased trees came down, the stumps were loaded into a 30 yard dumpster – almost 12 tons worth. That is a staggering number, and it explains why so many large machines are parked in the front yard. Taking apart an old landscape and driveway is a shocking experience, but bare dirt that is asking to be regraded is a big breath of fresh air. It is never an easy thing to abandon what was, and go on.

a new driveway (12)Once the drive curbs and the trees were removed, the ground had to be graded.  In this case, there was quite a bit of what I call balancing to do.  The land which was high on one side was lowered, and the low side needed to come up.  From the street, the land would look balanced, left to right.

a new driveway (4)The grade of the driveway would determine the final grade of all of the land surrounding it. A large motor court some 56′ feet wide by 32′ deep would be a dominant feature of the landscape. This would permit off street parking for clients who entertain regularly. But most importantly, a gravel drive and motor court seems appropriate for a house of this age and architecture. It interests me that many very old homes with motor courts were built before the advent of motor traffic. It can be a beautiful feature in and of itself. The accompanying landscape would in a simple way feature the house and gravel court.

a new driveway (2)In many respects a gravel drive is simpler and somewhat less expensive to install than concrete, asphalt, or stone.  One of the biggest expenses is the cost of the edging. The gravel must be contained.  A hard boundary is what keeps the gravel in place.  Gravel that has crept away from its intended location can look great in a very informal setting. It would look messy and untended in a house of this architectural formality.

a new driveway (3)
Both the drive and motor court are edged in 1/4″ thick steel.  That steel edges is secured by steel stakes that are driven into the ground through steel loops welded to the back of the edging. The steel has to be this thick to withstand repeated vehicular traffic, and stay in place.

a new driveway (6)The gravel motor court will be bordered in concrete paver brick, three bricks deep.  The border will help to visually reduce the size of the gravel area. It will also recall the brick on the house. This brick will be dry laid between parallel bands of steel edging.  Concrete brick can better withstand compression weight of a vehicle. Pictured above is a base layer of compacted road gravel.  The finished crushed stone will be added at the very last, at the height you see indicated by the top of the steel edging.
a new driveway (5)A large new blue stone front walk will make beautifully clear the location of the front door. The house is not symmetrical in its footprint.  The walk which is large enough to feel like a terrace is a centering gesture. There is plenty of room for containers out away from the front door. This exterior entry way echoes the scale of the spacious foyer just inside.

a new driveway (9)An important element of designing any driveway is to check if it is driveable.  My clients drove it a number of times when the scheme was painted on the ground. One little but significant change was made to help anyone backing down the drive stay in the lane. A driveway that doesn’t work well always shows where that pinch point is. Curves and changes of direction need to be gradual and sweeping.

gravel drivewayThe drive at the back will be installed as concrete aggregate, rather than compacted gravel. This will make it easy to shovel a path from the detached garage to the back door. The forms are being set for this portion of the drive. An iron fence and gate appropriate to the architecture is to come soon.

a new gravel driveway (3)The bed lines near the gate to the back yard were specifically set to allow my clients to back out of the garage, and turn around.

a new gravel driveway (2)As of late yesterday, the finish gravel has been put down in the motor court. The concrete brick is due to come in today.

a new gravel driveway (1)At the last of the day, a pair of 25 foot multitrunked katsura trees were added to frame the view of the house from the road. The landscape will be underway shortly.

 

Decomposed Granite

gravelThere are some landscape materials I cannot get enough of.  Decomposed granite is a material comprised of pieces of granite 3/8ths of an inch across, and smaller.  The smaller pieces are known as “fines”.  The fines sift down in between the 3/8 inch pieces, and interlock the decomposed granite.  This makes for a surface that delivers that beautiful sound with every step that says garden, dead ahead.  Decomposed granite looks like sand when it is delivered.  I have taken plenty of panic stricken phone calls from clients.  But once it is laid down, graded, compacted and washed, it is a surface that won’t give no matter how high those heels are.  I have no love for asphalt as a surface; does it not seem like a symbol of all those places we have paved over without cause?  Concrete is a great material, as long as it is used with architecture that asks for it.  Concrete aggregate is beautiful for modern or contemporary landscapes-I hate to see it used by a client who really wanted gravel, but was too afraid.  My mentor and dear friend Al Goldner, told me once his only regret as a designer was that he was not bold enough; be bold!  

gravel1Decomposed granite, properly installed, makes for a driveway impervious to tire marks.  In this landscape, the driveway flowed seamlessly into paths for  a vegetable and cutting garden.

gravel2A driveway of decomposed granite requires an expert installation.  GP Enterprises does these drives for me.  They are so careful to install with a careful eye to grade and drainage.  They compact the granite with the same machinery that compacts asphalt. 

gravel42Decomposed granite makes a great mulch for comtemporary landscapes.  This landscape did not ask for mulch-that granite completed a thought. 

gravel5Decomposed granite can finish a formal planting, as well as a contemporary one.  It is clean, fresh, and crisp.  It is easy to make shapes, and moves; it does a great job of giving the eye a place to rest.

gravel7I have done many a terrace in decomposed granite.  It is a clean surface, not so demanding of attention as stone. This garden makes much of the pots and the furniture-the granite is a quietly beautiful  surface. It is the color of nature, a texture that celebrates all that is set on it. 

gravelbThis material is useful for more than driveways and paths.  Some plantings need a special space of their own.

gravel9Wherever people may be in a landscape, I wonder if this surface will play a part. The granite did a great job of featuring the stone from the 1920’s original to this garden. 

Some materials are so versatile, which makes decomposed granite  a major player in my palette of hard surfaces.  Great for driveways, friendly to plants-amazing how it can work in contemporary landscapes as well as vintage ones.