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I was just curious to what other people use for bases for patios & walks. I use stone dust for everything, I tried reclaimed concrete a few times, but to much junk mixed in with it. Thanks for the info
What you should be using is crushed stones (3/4" stone down to fines). This is the proper base material by industry specifications (ICPI, AASHTO, NCMA...). This base material when installed properly will resist any movement due to freeze thaw, will resist rutting on driveways and will hold up forever. Interesting note this is the same base that many states specify for use under paved roads ( although they use substantially thicker applications ). This material compacts well (able to achieve 95% of modified proctor density and has an ASTM specification). This mean that everytime you purchase base material you know that you are getting consistent quality ( if you doubt the quality ask to see the sieve analysis, any reputable quarry will have this available).<br>Typical base thickness for a patio or walkway is 4", compacted in 2" lifts using a vibratory plate compactor (at least 5,000 lbs force).<br>Why you shouldn't use stone dust! Stone dust does not have any specification so you have no way of knowing if your base is consistent between loads or on different jobs. If you provide a warranty of your work (minimum of five years for pavers) you had better know that your base is done properly and with consistent materials. In addition to this stonedust also contains a high percentage of very fine material which holds on to moisture much like a high clay content soil. This will cause shifting and "pumping" on many applications. For more information on this subject please go to www.icpi.org or www.belgardhardscapes.com (view the installation guide that is available)<br>If you are wondering why you should listen to me it is because I train companies on the proper installation of pavers and how to improve their efficiency. I have trained dozens of companies to become both better and more efficient. I am also ICPI certified in the sales and marketing of Interlocking Concrete Pavers.
EDL<br>Chris DEFINITELY knows what he's talking about. If you use the proper base materials and install methods you can do a quality job with very few call-backs for problems and make good $$.<br>If you're wondering why that technical stuff is so important, its because putting in the base properly is 70% of the job and the most critical part of the install. It doesn't matter how pretty the surface is if the base fails and you can't make money on the day you have to go back and re-install that patio for an unhappy customer.<p>----------<br>Lanelle<br>
EDL - This is a bit of a 'nuts and bolts' explanation on the differences in the stone you use and the stone reccommended to you. I did a job in New York state about 10 years ago, and being unfamiliar with the territory (I grew up in Michigan, operate a hardscape/softscape business in Wisconsin), I used what was reccommended to me, which was stone dust. If you hold stone dust in your hand and look at it, it isn't very angular. It's more like big black grains of sand. In Metro Detroit (Michigan) (at least this was true about seven years ago) foundry or 'slag' sand was the overwhelming choice. It's more angular, holds together well, but it's clearly not a good choice now, or at best a risky one. Foundry sands have levels of Cadmium and Lead in them. These two elements cause all kinds of biological problems, but only when their levels are too high. So how can you be sure? You have to contact the foundry the slag comes from every few months and get their test results to be sure the slag is safe. Way too much hassle, especially for something that could harm the children of your customers. In Wisconsin we have huge quantities of limestone. That's what my company uses. This stone is very angular. The reason you want angularity is because the individual stones lock together better and resist movement better than non-angular stones do (ever walk on a beach? The grains are very round, or non-angular. The sand squishes right out under your feet, doesn't it? Same thing with stone dust, over time. And don't get me started on the use of sand over that stone base). Check your local quarries for what they supply for road base. It'll be called something like crusher run, or 3/4- (pronounced three-quarter minus). Depending on what part of the country you live in (I'm guessing East Coast), the base thickness will vary - if you live in Texas, an inch will likely do, for pedestrian traffic. In my neck of the woods, AASHTO specs 4" of stone, but I use 6", for two reasons: 1) better prepared base, and 2) customers will be impressed. In talking this issue over with a few civil engineers (you could do the same where you live), anything over 4", for PEDESTRIAN traffic, isn't necessary. For work I install, of that 6", about 4-5" is 3/4-, the rest is limestone screenings (from about 1/4 down to dust). If you have more questions (and don't live in Wisconsin, i.e. competition of mine), let me know. I started paving with brick in 1985, and have laid a few square feet.
First some definitions from my area:<br>3/4" Crushed stone - trap rock crushed to 3/4" size, no fines.<p>3/4" Processed stone - trap rock crushed to 3/4" including fines.<p>Stone Dust - the fines as mentioned above.<p>Stone Sand - the fines from crushed stone that is softer than trap rock.<p>What we call stone dust here in CT is the same as the fines you would have in 3/4" processed stone (as opposed to 3/4" clean). The stone is called trap rock, and seems to work fine since it is hard and drains well. Depending upon the excavation we use a base of compacted crushed stone, then processed stone with the final layer of stone dust put on top (about 2" and compacted. This is similar to road base in my judgement, and the stone dust we stock is very consistent. We use it because its recommended to us by paver distributors. Some contractors screed a layer of mason's sand on top of the processed base to level out the surface, but that inevitably walks (or squishes out). Does the stone dust that we are using sound ok or should I be working right on top of the processed stone. The material called stone sand is soft to the touch, and would level well, but not compact. Does it sound like we are using the right material or should I be using the processed stone minus the last 2" of stone dust? Am I correct to assume that since the stone dust compacts well that it is OK? Sorry to be so long winded. <p>----------<br>Phil Grande - Soundview Landscape Supply - http://members.aol.com/slsnursery<br>Ivy League Landscaping - http://members.aol.com/scagrider
We use a graded stone call CA-6 state inspected 3/4"- a limestone that gives us stable base. Most problems with any type of base is what is under the stone ie: soil types and its drainage. Most of you have seen a road failure, well it's the same thing. soil testing is the best way to determine if the soil will carry the load or if you can't use a fabric underlayment at least 2' past your layout. Masons sand will not work under pavers, it's to fine you need a coarse angular sand,this is what locks the pavers together. Stone dust will deteriorate over time and fail. Reclaimed concrete will work if it has enough fines. most times it's not graded and cleaned right. The most important rule find out where your material is comming from and if you think it's bad don't use it, they can and do send out bad loads, just reject the material and get another load. Tampers are not all made the same ( know I have about 5 that I have sold in the last year and have tried about 5 more that just don't hit hard enough.) We have moved to rollers mounted on our skid steers and just bought a 9 ton vibratory, this thing can really make base. As to questions on base here is haw we do it: 6" base 3/4- stone compacted in 2" or less lifts, check base with straight edge fill any voids,remove any high spots then recompact, screed out 1" coarse sand, trowel out any marks and edges install pavers.
The coarse angular sand that Paul referred to is called 'concrete sand' in our area. And he's absolutely right. Stone dust will break down over time. <br>The soil test is important. In our area we have very heavy clay, so we expect to have to use a geo-textile (not landscape fabric or filter cloth) between the soil and the base. This gives us the assurance that the base can't sink into the wet clay during a rainy season.
Hey Paul - <p>What is your typical paving project size? The equipment you're using sounds huge to me relative to the residential (pedestrian traffic) projects we do, and relative to the base depth you use. Are you doing mainly commercial projects? And, I don't like using any sand in the base - I build up the base w/ 3/4"- (lifts of about 3", and for the top inch or so I set screed rails, screed and compact 3-5X. Final screed is not compacted. I think my way is probably much slower, but I like the long term results better (than using sand). Your thoughts?
Some are as small as 500 sq.ft to our largest of 22,000 sq. ft. <br>Your missing the point the sand is what actually locks the pavers together, by passing the plate tamper over the loose sand you force the paver down into the sand and sand into the joints. All you should do then is sweep sand into the top 1/2" of paver. Our jobs are Parks and Forest Preserves. The large equipment reduces time on the job controling labor and improving costs. After twenty years of being kicked in the pants, iron is CHEAP, labor is expensive used only once and sometimes hard to keep. The easier you make it for your men the faster they will produce,the more money you will make. If you have a chance vist my web page, it needs updating but shows the type of work that we do.<p>----------<br>paul<br>
I agree re: labor vs iron. I'm also certain that finding good labor there is as tough as it is here. The reason I asked about the big equipment is because I was trying to picture using a vibratory roller attachment on a skidloader in the tight confines of my typical residential backyard, and residential patio prep area, and it seems like for a small job like that (300-700 sqft), you'd have trouble in tight turns, and since most of it would be tight turns, it would just create a big headache.<p>As for the sand, while I use it to sweep in over the top, then compact (x2) for interlock, I usually have two reasons not to use it in the base for every one reason given for using it (try me ). Like I said, I think my way takes longer, so if that makes me less competitive, so be it. But I would argue for quite awhile about a difference in efficacy between the two methods. By the way, I checked out your website - beautiful stone walls! For that riverbank project, did you have to temporarily reroute/damn off any water? It looks like a project that came with many sleepless nights, but a certain portfolio boost.