Any stone that is dry-set has the potential to shift over time. Square and rectangular cut bluestone is not prone to horizontal movement because the edges are cut square and vertically flat, and the joints are small, uniform, and filled with stonedust or sand, all of which prevents the stones from moving side to side. They can and will, however, move vertically (heaving) if the base isn't prepared properly.

Irregular bluestone (also called broken bluestone) does not have the neat and clean cut edges that the former has. The edges are, in fact, broken, with no discernable face to trap the stone dust or sand between it and the adjacent stone. Also, as the nature of the stone is both irregular and broken, joints between the stones will be large and irregular. This condition will allow for horizontal movement of the stones due to the pressures of pedestrian traffic and weather.

Now, all of this does not mean that broken bluestone can't used in a dry-set fashion. It simply means that there will be no guarantee that they'll stay where they're put as time and seasons go by.

So, treebeard, since you are knowledgeable about this, here's a related question. What exactly makes a good base for bluestone or granite pavers? I was taught to go below the frost line but the masons are telling me that is not necessary. This is for my front walk and I don't want the stones going anywhere, up or down or sideways.

And what is the best material? I like granite but how thick and how big--width and length and depth?

And is mortar better than dry-laid? I want a permanent walkway that will last at least as long as I do!

thanks treebeard ... when you say the irregular might move horizontal over what period of time - don't want to be resetting every year?
I really like the irregular, not crazy about the square,
my other choice is concrete tumbled pavers (although I like the look of bluestone better), but i am afraid i might get efflourence since it's so shady - any thoughts?

A couple of years ago I dry laid a small path of flat bluestone that was dug out of the beds. That was in about 2" of sand, and hasn't shifted at all. While I was in the process of doing it, we had our front porch redone and the mason recommended stone dust instead of sand. So the next piece was stone dust. I just finished it this spring, so can't comment on it's longevity.

We bought the house with a dry-laid brick walkway to the back door. For various reasons, it's been taken up and reset at least once by us. It's not a difficult job at all, as long as I remember to wear work gloves.

Something to keep in mind, is that the broken stones tend to be smaller, so there are more edges to catch snow shovel edges and things like that. My walkways are in the middle of the garden, and not meant to be maintained during the winter.

The idea of going 'below the frostline' is really something that has more to do with the construction of habitable space...like a building of home. It's really quite amazing how much power can be put forth by water in the freeze-thaw cycle. Foundations that don't extend below the local frostline can, indeed, be heaved by the freezing of groundwater. And then, as the water thaws, whatever has been lifted will settle back, but not always to the same place it was originally. And it really only takes a little bit of vertical movement on a foundation to crack the concrete, the sheetrock walls, the ceilings, etc. It doesn't take much at all. And, as anyone who has been faced with it knows, the costs of repairs to such heaving can be outrageous.

Walkways and patios aren't looked upon with the same serious concern as the house, even though costs of repairs after heaving can be hefty. After all, it's only a walkway, right? Well, perhaps not if it's 'your' walk, and 'your' money.

Normally, bed preparation for a walkway doesn't exceed 12" or so. Dry set walkways should be founded upon material that is free-draining, which really just means that water won't just sit there...it will drain 'through' the material and keep going...to where ever it's going. The dryer the material in the winter, the less likely it will be to heave. Around here, we use a range of materials for the base beneath a dry-set design. Gravel (around here that a native mix of sand and small stone), and crusher-run (crushed stone that contains both fine and coarse aggregate all being angular, which compact better) are the most common materials. They're both free-draining and they can both be compacted very tightly. Sand is sometimes used by some folks, but as the tiny particles of stone that make up sand are mostly rounded in form, they tend to not compact as will as the others (in a sense it can be like trying to compact ball bearings). And there's crushed stone, which has a variety of sizes (usually 1/2" to 3/4" or larger) but no finer particles. It can be compacted well enough, and it's free-draining. But as it has only larger particles, finer material placed on top will eventually filter down into it, allowing the surface to drop.

I like crusher-run myself. A vibratory plate compactor (the size of a lawn mower) can compact it quite well.

For mortar set stonework, bluestone or granite, a cast-in-place concrete base is best. If I were doing it, I'd place some standard concrete reinforcing wire right at mid-depth in that slab to keep it from moving when it cracks, and it will crack. On top of that slab, the mortar setting bed can be installed, and then the stones set in the bed.

As to the best stone...it's a toss-up and really has more to do with your taste than the strength of the stone. Both bluestone and granite are noteworhty in their ability to endure New England winters. Bluestone will be found most often in a 1 1/2" thickness, although thicker is available (for extra cost). I've found the standard thickness to be quite adequate. But note that bluestone, while cut to exacting sizes for length and width, will not be entirely uniform in thickness, so if you're picking it yourself, I'd tend to stay on the thicker side, at least 1 1/2 inches. Same with granite. The length and width of the individual stones will depend on 2 things...your design, and the strength of the installer. The bigger the stone, the heavier and harder to handle. If set correctly, the size should not be a concern for movement. The largest regularly available size in bluestone is 30"x30". I'm guessing that granite is about the same. Sizes change in 6" increments. Your 'pattern' will determine size.

AS to whether mortar is better than dry-set, it really depends on quality of installation. I've seen mortared installations come apart quite readily when the slab and setting beds weren't constructed properly. And I've seen some that will last forever. Same with dry-set. If the base is set on uncompacted soils that are very wet, it doesn't matter what you do on top. It will come apart. I've also seen dry-set installations that will last a very long time.

Dry-set installations can see weeds growing in the joints, as weeds will grow anywhere. They will also need periodic addition of joint materials as the weather and foot traffic can move them. Concrete installations may be more costly.

The 'look' is what you should determine first. Then find a competent contractor to work.

Regarding the movement of irregular bluestone, it could be a year or two, or a week or two before you see movement. As with the information above, bed preparation and compaction will be the keys.Making sure that the stones are completely bedded without air pockets beneath them is also important. Going with a thicker and heavier stone will also help to prevent the stones from moving due to foot traffic. Thickness at the edge is a good thing to look for in a stone, too. The more the edge maintains the thickness of the stone the better.

As for tumbled pavers, I can't say, for I've never used the...and probably won't. They're just not my style.

Wow, treebeard, that is a lot of extremely useful information. You should write it up for a garden magazine...like PPP. For my walk, I want no movement and as little ongoing maintenance as possible...I'm already swamped. And I love our native granite. Granite is forever.

The key, which you mentioned, is finding the right contractor. There's the rub. I've seen 100-year-old jobs that are still perfect--and recent ones falling apart. Finding the right craftsman is the hardest part of the job. Thanks again for all the good advice.

Great post, treebeard!

I've laid DIY brick and bluestone pathways and patios, using sand or what we call stone dust as a base, with sand between the joints.

Installing a border of some kind helps to keep the paving material from moving laterally in dry-laid paths. I've used steel edging, bricks laid on their sides, and cedar 2 x 4s, and am about to try some heavy-duty plastic edging for a semi-circular path.

My paths require some maintenance, at minimum an annual application of sand swept into the cracks. They've held up really well over the 15 years I've been building them, and it's really satisfying work. If I don't have a pallet of bricks somewhere in my yard, I feel like something's missing!

so irregular bluestone can be dry laid ... now i guess i need to find someone who can do this with good results ...
what should I ask the mason about his process to have a good feeling he knows what he is doing with regard to dry-laid irregular bluestone.

Thank you! Perfect timing! I haven't visited this site for awhile, but my husband's childhood home is being torn down by the Rhode Island airport corporation. They paid a handsome sum to his parents. They were ready to go into a senior center anyway. But the one thing I had my husband do, was tear up the bluestone walkway, which was dry set, going up to the front of the house. It hadn't had anything done to it for over 50 years! Now I admit it wasn't used all that much, as everyone came in the side door by the garage. I was planning on using the stone as a path in my garden. It will not be walked on that much. All this information is very helpful as I plan on doing this myself. Luckily it isn't a very long path.

Just be careful, hostaz6a, I started small too. You can get hooked on this kind of work, and before you know it, you too may have the perpetual pallet of stone or brick and a half yard of sand or crushed stone someplace in your yard.

This has been an extremely timely thread for me, too. We're still trying to put together a garage project and as it will be detached a proper pathway to it will be key. We have to deal with snow removal and use a snowblower, so the surface must be relatively uniform and it must drain freely.

I agree with the others, treebeard, your's was an excellent, informative post. Thanks!

Could you comment on edging that will create a pleasing arc, keep grass from invading a dry laid pathway, and provide an easily mowable edge?

I like the heavy steel edging that almost disappears when in place. I'm about to try some heavy-duty platic that should also be invisible, I bought it because I couldn't find the heavy steel and I thought it would be easier to use - I can't cut the steel. Can't comment on the plastic yet, because we keep postponing the curved part of the walk.

Even with the steel, which is set just at the level of the tops of the bricks, some grass finds its way over into the path. It's eaasy to pull it, using an old kitchen knife; I do this every year or two.

Help! I just got 2 quotes for wet laid irregular bluestone ... One was almost the double the other. The more expensive quote was from someone very crafty ... however I can't figure how there could be such a difference. I don't mind paying a little extra for craftsmanship. Howvever I am thinking are there different ways to prepare the underlying surface. The more expensive guy said he would lay cement with metal and then lay the bluestone. Is this standard or oare there other ways (less costly) to wet lay?

Treebeard, if you can stand it, one more question. I would like to install a granite front walk. It must be able to withstand shoveling in the winter and, as it is in full shade, nothing really melts til spring. It has to be smooth and safe to walk on, as it is the main entrance to my house. And I want it to last as close to forever as I can get, even if I have to pay more now.

Which is better? Granite blocks the size of Belgian blocks or bricks? Or larger pieces of granite? How thick is best? Function is critical; then looks. Thanks for the help.

Ginny,

If you're looking for a relatively 'smooth' walking surface, I'd stay away from the Belgian block (cobble) type pavers. The surface of the 'block' style is usually quite irregular. Granite pavers are also sold in sizes similar to bluestone, so the same kind of pattern can be achieved. The surface of these larger pavers is 'flamed' or 'thermal', and makes for a comfortable walking surface. The Stoneyard in Littleton is a good place to start looking for what's available, if you're not too far away from there (they have a website...)

Most of our granite or bluestone paved areas are on the east, west, or north sides of the house...none are on the wide-open-to-the-sun south side...(duh...), but we haven't experienced anything out of the ordinary with them regarding breakage, heaving, or difficulty keeping clear of snow and ice.

As with any 'smooth' pavers, one must keep in mind that the relative safety of the walking surface does depend in part on the slope of the surface. Too much slope and there will be little one can do to keep it safe all the time in rain, snow, or ice.

As for thickness, most granite pavers (other than the cobble-belgian block style) are available in 1" or 2" nominal thickness. Note that the 'nominal' in granite is a little closer to 'actual' than bluestone as the granite pieces are actually 'cut' not 'split'. I tend to stay with the thicker pieces in both granite and bluestone, but much of that depends on whether you're doing the work yourself, or hiring the strong-backed brawny outdoorsmen landscapers who toss that stuff around like it's nothing. There is some weight to the stones...just like bluestone, maybe a tad more.

A walkway paved with either bluestone or granite can be shoveled in the winter quite easily, but one must remember that it's virtually impossible to get each and every block set perfectly level with its neighbor. While these slight variations in the surface height will not impede the pedestrian or make for a dangerous walkway (unless they're really poorly set) they can prevent the snow shovel from being used in a 'plow-like' fashion. As I've found on my own granite and bluestone walks, a slight height variation between the stones will stop the shovel cold and suddenly if you're pushing it along. But as long as one understands that and accepts it, and 'shovels' rather than 'plows' it's a very durable and safe walking surface. I tend not to use rock salt on them in the winter, but when we have those infrequent 'icing' storms where it can't be avoided, I'll use deicers (as one gets a the hardware or big-box store in the large tub).

Chelone,

Regarding 'edging', I'm sorry that I can't comment knowledgably (did I spell that right?) on the subject...if you're talking about the standard steel or plastic edging that is available on the market. I tend not to use them. If I edge a walkway or paved surface at all, I tend to stay with the same material used to pave the surface of the walk. With bluestone, unless we're in the mood to do a lot of cutting, we allow the edge to be the edge of the pattern. Sometimes this is planned to be straight, sometimes just the random edge of the stones as they progress towards the other end...irregular and looking for all the world like it wasn't completed. Once the gardens or lawn that the edge meets is grown in, the resulting 'line' can be quite pleasing. If we simply use the base and joint filling stone dust right out to the edge, we will be faced with regular maintenance to keep the edge and joints grass and weed free. We make that decision knowing what we're doing. Other times, we'll set the outer most pavers in a thick mortar bed that extends deeper into the sub-base course than the dust we use to set the bulk of the walkway. By its nature, the mortar will push up into the joints as the pavers are set, but not so much that the dust can't be used to cover it at the edges. But that's us and how we work. Others we know swear by the steel or plastic edging and use it frequently. When using it in with a paving pattern that has curves and is not all that straight, parallel, and perpendicular, it can make for a lot of cutting of whatever material is being used for paving...even when using the modular concrete blocks.

Hope that helps a little.

Here is a link that might be useful: The Stoneyard -Granite Pavers

Great help, Treebeard, and a great link. I have already emailed them. All I need now is a mason...The wonderful man who did our masonry, a true artist in stone and right from Sicily, retired and moved to Florida, and this is more than I can take on. Thank you very much for all the help!

Treebeard,

Thanks so much for your time and consideration. It was very helpful! The path to the proposed garage will be curved and likely 5' wide, lawn on one side and a planting on the opposite. I am now better informed as to the realities and constraints the various paving options provide.

thanks for the advice mich ....
we are getting close to a decision here ... we
are now considering either wet laid irregular bluestone
or wet laid brick pavers (although my fear here is the clay
brick possibly cracking). We like the look of brick pavers dry laid, but are fearful of the the maintenance (weeds) and possible movement, since this is a front walkway which will be used quite often. On the other hand we have heard that blustone can be slippery when wet? Any thoughts?

Any surface can be slippery when wet. Some are, of course, more so than others. Bluestone, granite, and even concrete can be slippery, as can the brick, but the brick, like broom swept concrete, has a slightly rougher surface that will provide some additional traction. But, as I said above, if the surface is steep enough, nothing will prevent it from being slippery.

As for the brick, any brick that is made specifically as a 'paver' should not be as susceptible to cracking as old recycled building brick that many use.

Weeds in the joints of a dry set installation are, and always will be, a fact of life. Vigilance to make sure that they don't become too well established is the key. And yes, it does require some effort on the part of the owner to maintain, but then again, there really isn't anything in life worth having that doesn't require some regular attention.

The maintenance on a brick or bluestone walkway is something you can do yourself, assuming that you're reasonably able-bodied. Compare that to the potential repairs on a walk that is set in mortar or concrete. When those require work, which they sometimes do, it means calling a bricklayer. Almost inevitably, he'll want to rip up the whole thing and start over!

Not to dissuade you, because wet-laid walks are also beautiful and durable; just another point to consider.

I had about 900 sq ft of bluestone walkways and patios laid last summer. I had made it clear that i wanted it handicapped accessible as i have wheelchair bound friend. So, the gaps between the stones are too large for the wheelchair - they are filled with sand (and weeds).
What kind of grout can i install in the gaps and should i use any kind of sealant/ enhancer/ cleaner before i do so?
I learned the hard way installing slate without a sealant before grouting indoors... Help anyone? did i mention the 900 sq ft?
I also want to make stepping stones directly in the earth with concrete and lay the scrap stone on top.. any ideas there too?
Thanks to anyone who can give me direction!

Hi Treebeard,
We are getting close to starting on a walkway. We have decided to go with square bluestone wet laid with a slight curve (like a half moon shape). we are talking about 260-285 square feet (about 46x4 and then about 8 1/2-10x8 1/2-10 front entrance) . One stone mason said it would take him about 7 days to rip old concrete walkway, prepare and lay the new walkway. The other said 2 days total. I asked the 2nd about the prep and he said a "rough" concrete base then the bluestone laid in concrete. I asked about drainage and pitch and both said don't worry we'll take care of it... is there anything special to be aware of here? I asked about cracking and any use of expansion joints. The 2nd guy mentioned he could cut with the saw tiny "expansion joints" every 8 feet. Will this help? I have seen the 2nd guy's bluestone walkway work and I like it. I just don't know how the 1st guy could spend 7-8 days and the other 2 days(BTW the 7-8 days guy is about 40% more costly). The 1st guy has a very good meticulous reputation in the area and we have seen his stone work .. although still like the look of the 2nd guy's walkway. We don't want to have problems down the road with any "corners" being cut? What is the recommended prep and installation process? and what is the recommended way to deal with "expansion" and/or prevent cracking? and drainage? and size if joints between the stones? Thanks.

Hi. I am looking to have an irregular blue stone pathway from front door to driveway. There is a slight downward slope. several estimates. One says only concrete setting, another says set stone in mortar and fill joints with stone dust and another says dry set is fine. I have another large walk on the side of my house tant they all agree dry set is fine stone dust between joints Help!

Hello. I do quite a bit of landscaping with installation and design of gardens, walkways, patios and stairs. We are in zone 5 and use broken bluestone or as it is known in this area standing bluestone, in a prepped base removing sub- surface stone and using 3/8 natural stone and dry lay the material. We use it very sucessfully as walkways, patios and stairs. Prior to the actual install, there is detailed attention to drainage and runoff from the houses roof or slope, where the water will run and how much is shed etc. In addition we can score and fit the stone to have a nice tight fit. To finish the project many clients wish to have a polymeric sand in the joints and spaces and it gives it a lovely finished appearance. It does not shift, buckle or heave. With the wonderful texture and vein colour, broken bluestone is a fabulous addition to the hardscape cache.

Hi me again, on the walkway we do not use stonedust as it does not drain, if you want it to drain throug. Of course there should be a slight pitch that is maintained while you are installing using your level. The stone dust will with heavy water from rain or drainage, run out of the cracks. Give the polymeric a try. It comes in a few colours to compliment your project. Install it carefully, following the instructions. Ask you local dealer for the heavier grade. It is only a bit more in cost and the wearability is worth every cent.