How To Install A Flagstone Path In A Lawn

Hardscape, How-To's · Written by Roger

152 Comments

flagstone.instl_in-lawn1aThe look of natural flagstone set in grass can be beautiful if done correctly and used in the right situation.

The turf in-between the stones softens the overall look of the path which can help distinguish it from other primary walkways.  At the same time this technique can subtly  connect different “points” in the landscape and direct the eye and traffic.

From a practical standpoint the stone path gives everybody a clean, solid surface to walk on in the event the grass is wet and/or soft.

The process of installing a path like this will vary slightly depending on circumstances such as the condition of the existing lawn.   Or, perhaps there is no lawn to begin with and you want to achieve this look.

The following installation will show the fundamentals.  If you have questions on a particular circumstance you may be dealing with, leave a “comment” and I’ll help you out.

Flagstone selection

Flagstone path stone selection

Flagstone Quality And Layout Are Important

Choose a type of flagstone that is dense and solid.  Stay away from slates and other types that flake, fragment and deteriorate over time.

You want the majority of pieces to be larger in size and no less than 1.5″ thick.  The idea here is that greater size and weight give stability – this is key.

Purchase and layout a good selection of flagstone so you have pieces to choose from.  Notice how plywood is used to protect the paver driveway.

Flagstone path layout

Flagstone path layout

Before you begin the actual site work and preparation, arrange the stones on top of the existing lawn how you would ultimately like them to look.

In this picture to the right the stones are set and ready to be installed.  The homeowner requested that the space between the stones be kept close.  Compare this to the first photo at the top.  This is a different project where spacing was made wider.  Keep in mind the spacing must be wide enough to support the living grass.  Arrange the flagstones no closer than 1.5 – 2.0″ apart.

Remove existing lawn

Remove existing lawn

Preparation And Installation Of Flagstone

The next step after arranging the flagstones is to prepare the base for installation.

Step one, removing the existing lawn, was fairly easy on this job.  The grass happened to be recently planted sod and was not yet deeply rooted.

Working in sections, move 3 – 4 stones at a time off to the side.  The sod can then be peeled back and the stones replaced to their set positions.

Realize, of course, that if you had a well established lawn, removing it would most likely involve some other strategy.  Again, which tactic you use to remove the grass depends on the circumstances.

Base preparation and flagstone setting

Base preparation and flagstone setting

With the flagstones now sitting on bare ground, you are ready to prepare the base on which you’ll set the stones.

Trace the outline of the stone on the ground with a pointed tool of some sort – a trowel works fine.  Using a spade dig down 5 – 6″ within the outlined area.

In this excavated space install 3 – 4″ of crushed gravel.  We like to use gravel no larger than 1/4″ diameter.  It’s small enough to “move & level” with a trowel, compacts well and drains nicely too.

Now sometimes it gets difficult during this base preparation to preserve the narrower strips of earth between stones.  The key is to preserve or replace soil in these narrow strips so they can support grass. If it becomes too difficult to preserve these narrow strips of soil and they combine with the gravel base, take care to ultimately fill these voids with as much soil as possible.  For grass to survive in that narrow space, it must have a deep root system in soil.

Flagstone can be cut if necessary

Flagstone can be cut if necessary

A flagstone path in a lawn is meant to be informal.  Although you can see line design and pattern, there is still irregular shapes in the stone.  The pattern, which unifies the path, is achieved by relating the shape of each stone to one another.

Sometimes, no matter how much stone you have to pick from, you simply can’t find a good match.  This is the time to create the shape yourself by cutting the stone.

In the picture above we’ve arranged the path to widen at the top of a stairway.  Unable to find a stone to fit the situation, we overlapped one stone over another.

Flagstone cut and installed

Flagstone cut and installed

Before making the cut we first mark a line on the bottom stone.  This line mirrors the shape of the stone above with a 2″ space.

The cut is actually made with a diamond blade.  Although diamond blades can be fitted on different types of power saws, here a 2 stroke cut-off saw was used.

After the cut is made the fresh-cut edge is “distressed” with a mason’s hammer to make it look more natural.

This last picture also shows a string-line set up.  The string is set at an equal height from the “finish grade” at each end of the walk.  You can check the uniformity of height and pitch of your walk by referencing this line at any point.  Realize, however, that there are times when your walk’s finished height may have to follow a particular grade contour that is critical for drainage.  Again, this is a particular circumstance you’ll have to identify on your site and adjust to accordingly.

The basic tools for actually setting the flagstones are a mason’s trowel and rubber mallet. The trowel lets you move and adjust the gravel base while the rubber mallet lets you tap the surface of the stones to set them firmly.  As mentioned, the string line is helpful to check your walk’s height and pitch.  A tape measure is used constantly.  And last but not least, a bubble-level is important to check each stone.  Also, by bridging the level from one stone to the next you can check the “height / pitch” relationship of one stone to the other.

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    152 Responses to “How To Install A Flagstone Path In A Lawn”

    1. Matthew Says:

      Hello roger
      I’ve read through all of your comments and they’ve really helped. I’m doing a flagstone walkway for the first time here in San Antonio tx. My question is is there a way that you figure out how much material for the base to purchase? I don’t want to buy too little and would hate to get too much. Other than that I think I’ve got it. Thank you

    2. Roger Says:

      Matthew,
      To calculate the amount of material you will need to cover an area you need to know 2 things: 1) the square footage of the area, and 2) the depth of the planned material.

      To calculate the square footage of a square or rectangle simply multiply the length X width. For other shapes use one of these formulas.

      Once you have the square footage of the area, and know the depth of the material you plan to use, look up the amount you’ll need on this chart. The chart is applicable for any material you plan to use.

      If you’re not excavating the entire walkway area, but rather just under each individual flagstone, you can figure slightly less base material.

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