Random Cut Stone Flagstone Walk & Patio Patterns
Author: J. Jerrald Hayes; Published: May 15, 2009; Category: Masonry; Tags: None; No Comments
Given the variety of masonry products and materials the designs for masonry projects and in particular patios and walkways can seem to have almost endless possibilities. Working with flagstone alone the stone can be laid out in fitted irregular layouts like we did with the decking in our Hewlett Koi Pond project (photos 13, 14, 15, & 16) or using cut stone you can have an ordered geometric layout or one that is "random".
The trouble is in planning and designing Random Cut Flagstone Patios and Walkway people and even some professional masons are often stumped as to how to create a layout has a random look that that doesn’t generate a lot of wasted stone cutoffs. To accomplish that we use layout pattern that on a small scale looks random but on a larger macro scale repeats itself.
The trick is to produce a scale drawing of your project that defines the desired size and shape you want and to then lay scale drawing of the flagging pattern layout you find most pleasing to your taste (i.e. do you want your pattern to be predominantly small medium or large cut stones) over the top of your layout and piece the pattern templates together like a puzzle. To give a straight edge to the border of your layout when using patters such as these you use cuts from the stones on opposite side of the patterns to fill in the voids.
This plan (click for a larger view) illustrates how we used one of the patterns to layout a driveway entrance walkway with a quarter turn cut out of it to fit around and accent a nearby tree
The patio layout patterns illustrated below are based on module size of 100 sf each while the flagstone walkway patterns are 3′ and 4′ wide in 12′ long modules.
Typically in the Westchester & Fairfield county areas on masonry projects we see a lot of homes with walks and patios done in Pennsylvania Flagstone which comes from quarries in Pennsylvania and the southern New York tier and depending upon the quarry and even the lot or palette we see a full range of color encompassing blue, green, brown, lilac, rust, and gunmetal. The natural cleft ( the flagstone is cleaved it along its bedding plane) gives the surface of the stone subtle natural variations which adds to it character and we recommend a trip to visit one of our stone suppliers to see the colors and variations yourself.
In addition to the Pennsylvania Flagstone we also see Vermont Slate (which can have even more dramatic pronounced color variations) and gauged thermal cut bluestone stone which is stone with four sawn edges, a sawn back, and a thermal (flamed) top face. The bluestone exhibits some variation it is valued for its blue to gray color range.
Random Cut Flagstone Patio Patterns
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Random Cut Flagstone Walkway Patterns
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Setting the Stones
A flagstone patio or walkway can be laid wet in a bed of concrete or dry in a bed of sand or stone dust with the stone dust installation being our preferred method for most projects.
While laying the stones in wet concrete is an excellent method for a more permanent, maintenance free and "formal" looking patio it comes at a cost. In order to do it correctly so that the slab doesn’t crack due to frost heaving it’s a more involved process requiring a deeper excavation in which you build forms for a 4-inch thick concrete slab which has a grid of one-half inch steel reinforcing bars placed on two foot centers in it. The mason then comes back and lays the stones on top of the hardened slab typically in a 3/4 bed of mortar. While with a mortar bed you can use thinner stones (1" thick vs 1-1/2") and therefore less expensive stones the whole process uses more materials and more labor to install and therefore costs more than a dry stone dust installation.
We more often than not prefer to lay our flagstone dry in a bed of stone dust both because we think it has a more natural look to it and because if the ground underneath it does shift and move due to frost heaves in the winter or some other reason unlike concrete which can fracture and crack the dry laid bed has some flexibility and if for some reason it is damaged it is very easily repaired.
Regardless of whether we are laying a regular random pattern, a geometric, or a patio or walkway done with irregular flagging our dry laid method is basically the same. In poorly draining soil we’ll lay a sub bed of up to 6" of well compacted 3/4" trap rock (gravel) to promote drainage. On top of the trap rock layer we then put down a permeable membrane of landscape fabric over which we then put a 4" layer of stone dust. The landscape fabric filter membrane keeps the stone dust from infiltrating the trap rock layer while still allowing water to pass through and it also help prevent the roots of weeds from growing up or down through it too.
We prefer stone dust to sand for our bedding layer because stonedust compacts far beter than sand does. While some masons will argue that sand drains water away better than stone dust the difference between the two if any is tiny in that regard and the stability that compacted stone dust gives you is outstanding but making sure the base is well compacted regardless of the material selected is key.
Finishing the Installation
After laying the stones (in a dry laid stone dust installation) we fill the joints between the stones with stone dust that we then work down and pack into the joints with a tuck pointing trowel Tuck Pointing Trowel
