Recently I posted this project that we completed in Haworth, New Jersey for a client utilizing “thermal Bluestone Pavers” to create an outdoor patio living area. Although that was only three days ago, since then I’ve received four (4) phone calls relative to thermal bluestone pavers. Each inquiry pertained to a different aspect of these pavers such as sizes, thickness, etc.; so I’ve compiled a basic synopsis about them.

Pennsylvania Bluestone is dense, strong, fine-grained sandstone quarried only in the northeastern tier of Pennsylvania, parts of northern New Jersey and the southern tier of New York. It is an excellent material for decks and patios as it resists cracking and won’t discolor.  It easily can be separated into slabs of varying sizes, making it suitable for other architectural details such as steps, walls, entrance walkways, building facades, interior floors, and fireplaces.

Bluestone has a distinctive hard-yet-soft quality that makes it very appealing. Its texture is rough enough to provide traction in the rain, yet it’s smooth and soft enough to lie upon and bask in the sun.

What colors and textures are available?

Due to different clays and mineral deposits carried by groundwater during the stone’s formation, Pennsylvania Bluestone can vary from its predominantly silvery blue color to any combination of brown, tan, rust, green, and lilac. Full Range color encompasses all shades. For a more even effect, Select Blue or Blue-Blue includes variations of the silvery blue color only.

There are two choices of texture: natural cleft or sawn thermal.  A natural cleft surface is created when blocks of bluestone are sawn out of the ground and split on visible seams. The surface has a natural texture and is non-gauged, which means the thickness is approximate. Curly rippled texture is a variation on natural cleft.

What are some design considerations when planning a deck or patio?

The first thing to consider is location: is your deck or patio raised or at ground level, attached to the house or set farther away in a more natural setting?

If the patio is at ground level, you have the option of having it set in sand. Sand-set stone has the advantage of being permeable, but can also allow shifting which may cause it to become uneven over the years. Therefore it is HIGHLY recommended that this sand/fine stone base be heavily and evenly compacted to prevent this shifting. An installation of a minimum 4in. x 4in. treated timber retaining wall is recommended to maintain the integrity of the patio.

Another option, although more expensive, is the construction of perhaps a 2 ½ ft high retaining wall around the perimeter of the patio with entrances and even benches built into this retaining wall. Whether matching or contrasting colors and textures are utilized, this would result in a FANTASTIC appearance and be a stunning and functional outdoor living area.

What sizes do bluestone pavers come in?

Natural clef pattern and irregular flagstone are available in two major thicknesses: 1” and 1 ½”.  Because the thickness of these products results from natural separation along fault lines, the thickness is neither consistent nor exact.  The thickness of one piece will vary across the length and breadth of the piece.  If the thickness is generally between ½” and 1 ¼”, the flagstone is considered 1” flagstone. If the thickness is over 1 ¼”, it is generally considered 1 ½”.   When flagstone is particularly thin, i.e., ½” or less, it is separated out at ½” flagstone.  Some quarries will separate flagstone that is 3” or over into “heavy” flagstone.  The extra thin and extra thick material are frequently included in 1” and 1 ½” categories.

For dry setting application, you will need 1 ½” material.  This thickness is required to provide enough strength to handle minor shifts in the base and setting bed caused by geological and weather conditions.  The wet setting application, you will want 1” material. This thickness has less variation within and between pieces making it easier to compensate for those differences in the mortar base.

Thermal flagstone is cut to a nearly exact thickness, usually 1” or 1 ½”.  For dry setting, use 1 ½”.  For wet setting, either thickness is acceptable as there is no variation in thickness to be absorbed in the mortar bed.

How do you clean and maintain bluestone?

One of the great things about Pennsylvania Bluestone is that it does not need to be sealed, and it can be cleaned easily with a soft scrub brush and water. Vinegar or lemon diluted in water can be used for tougher stains. Bluestone can and often is power washed.

HOWEVER: A word of CAUTION…

NEVER power wash bluestone on the strongest setting when using a concentrated spray pattern. Doing so will often result in swirling lines visible on the stone, albeit though it is clean. NO amount of scrubbing will remove these swirls. The remedy is to power wash the stones again only this time with a low setting. And even this takes time, sometimes twice to remove your previous miscues.

almost PERFECT Landscaping offers pennsylvania bluestone paver installation and design and build services for both residential and commercial properties within the Bergen County, New Jersey area. If you need some help, hit us up on the contact page or phone (201) 389-6979.