Replies

1. 
   Eric_McRory | Apr 05, 2000 06:27am | #10

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   I have a similar situation in which I would like to cover up an old patio which is a black top on one side and concrete on the other. I've considered laying slate or sandstone pavers over the existing surface in a bed of mortor (rather than sand). Is this a bad idea to use the mortar bed rather than sand? It seems like the stone would move if laid in sand. Also, grouted joints don't grow weeds like sanded joints would. Please advise if you have input. Thankyou!

1. 
   Jim_Ronkainen | Apr 05, 2000 11:29pm | #11

   *I put in ~1500 square feet of pavers in upstate NY for my garage apron and sidewalk. The most important thing you can do to ensure a good and lasting job is preparing the base for the pavers properly. Make sure the base can drain and is adequate to support the loads you'll be putting on it. My garage apron had 12" of compacted crusher run stone and corrugated drain pipe under it plus a geotextile fabric under the stone. The sidewalk had ~6" of compacted stone under it. A 1" layer of sand went on top of the stone and then the pavers. After I laid the pavers, I put a little more sand on top of the pavers and compacted everything through a sheet of plywood.My guess is the prep I used for the sidewalk should work well for your patio.A word of caution - the roughness of the pavers will wear on your fingers. My finger tips were so smooth after that job that I had trouble picking up sheets of paper. Maybe I should have robbed a bank or something .......Good luck!

2. 
   Guest_ | Apr 06, 2000 12:34am | #12

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   If you want to do avers, you need to put down a good base. Sand will not do the job. For a patio you first need to lay down a fabric to prevent soil/rock migration. I use road fabric, buy it by the roll in 12' widths. Landscape fabric is OK. Then you need 4" minimum of 3/4" minus compacted well, 6" is better. Actually the thicker the better. Make sure the patio and subsurface drain well. Use a plate compactor on the 3/4" minus. When compacted the surface should be as firm as concrete. Cover your work if it looks like rain. I love working with pavers. They come in all shapes and colors and you can produce creative effects by mixing them. Our local manufacturer will even run custom colors if the order is large enough. Cutting pavers is tough, you need a diamond blade and a wet saw. Available at most rentals. Make sure you use a good edging material specific for pavers. 2x4 or 2x6's on edge will just heave out. You probably will need to resand annually. But then you will never have to worry about cracking.

1. 
   Guest_ | Apr 06, 2000 02:28am | #13

   *Climate is fairly dry, northern with extreme temps ranging from summer +35C to winter -45C. Average winter is about -15C or so. Soil is well drained.Thanks for the input. Scott, do you have any experience with something laid on top of a slab? The biggest reason I am sort of hinky about that is fearing the slab moving. Since I am trying to retire I don't mind a couple years of annual maintenance untl things settle down. But after that I don't want to work when I don't want to work.But putting something in like you mention herb sure looks good and is the way I was thinking; but it does require sanding and weeding every year.Maybe I need to change my mind?

3. 
   Bearmon_ | Apr 06, 2000 04:29pm | #14

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   FredB, you've received some good advice here about proper base, etc. I've been putting pavers in the ground for 15 years or more, and this year will do over 20,000 sq.ft. In a northern climate, a gravel base is essential. 3" of sand might work in Atlanta, but not up here. Follow advice given by Jim & herb above for base depth. Do thin layers and tamp like crazy with a plate compactor. Set final grade w/ a transit to achieve pitch.

   Contrary to common belief, the gravel underneath is not for drainage. It is to provide a firm base. The sand swept in the joints will harden after getting wet and then baked by the sun a few times. If you have a low spot in the paver surface, the water will just sit there. Drainage is achieved by pitching the surface. 1/8" per foot min., away from the house, of course.

   Wood borders are to be avoided, unless at least two courses of 6x6 spiked together. We once used a single 4x6 on edge for a border w 1/2" rebar driven through at opposite angles. It lifted the first winter, allowing sand to migrate under the 4x6, creating a nice trip hazard. The bricks were low and the wood was high. Fixed it for free, next winter it did the same thing. Tore it out and won't try it again. Lost a job a few years ago because I refused to do a 2x edge. Couldn't convince them it wouldn't work.

   Also would never consider going over a slab or blacktop. I wouldn't trust it not to move. If it moves, cracks or whatever, it will telegragh through to the pavers. Do it right, do it once.

   We try to get as much sand in the joints before we tamp the bricks as possible, then sweep more in after. Sometimes it needs a little more sand after the first winter, usually that takes care of it. As I mentioned in a different thread, you don't need to baby the pavers by putting wood down to tamp.

   Nothing comes up through all that tamped gravel, but airborne seed can land in the cracks and germinate. Pull 'em when you see 'em, and it is no big deal.

4. 
   Guest_ | Apr 06, 2000 04:29pm | #15

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   If I understand the discussion here -- pavers over a concrete slab in cold climate (we can get into below 0 f temps in winter, with large temperature differentials during the day) will, no matter what, heave?

   We have an as-yet-unfinished front porch. The existing base is 6-inch thick concrete slab. We were going to lay Endicott pavers over the slab, with mortar. So this will heave? Would some sort of expansion joints prevent heaving?

   Tina

1. 
   Guest_ | Apr 06, 2000 07:19pm | #16

   *Sanding is no big deal, maybe an hour or two a year. Yes you can get weeds sprouting up in the sand. Roundup or weed pulling takes care of this and it is a minor problem. Bearmon gave you some good advice on using a transit to make sure you have good drainage. After setting the drainage, I level the surface with a staight 2x6. Then add the sand. I use plastic 1" pipe to set the depth of the sand, and use a 2x6 placed on top of the pipe for leveling. Use dry sand. Setting pavers is labor intensive. They are heavy, a pallet of brick shaped pavers (108 sq feet) will weigh about 2600#.They have rough edges, so buy some good work gloves. Once in they are forgiving of mistakes. If you screw up, just pry up the offending pavers, two old screwdrivers will work, add or remove material and reset the pavers. And with a good base pavers are vitually indestructable. I had a back hoe loaded with retaining wall blocks run up and down one of my driveways without cracking or displacing one paver. Good luck on whatever decision you make.

1. 
   Guest_ | Apr 06, 2000 07:24pm | #17

   *The only thing I have done on a porch with pavers was to cover over a spaulded concrete surface with pavers. I bonded the outside perimeter pavers ( brick shaped ) and placed the inside pavers. I finished off by sanding between the pavers. It worked.

1. 
   Guest_ | Apr 07, 2000 08:04am | #19

   *The thing that's nice about the gravel-and-sand base is that if there is frost heave, it is unlikely to leave any lasting damage, and the pavers may well just settle back in the thaw. If not, lift them up, scrape a little sand, sprinkle it elsewhere, and put the pavers back. Mortar will crack.Ours were extra-thick -- 3"+ -- and incredibly strong. The truck had to leave the cubes in front of the house, and I moved them around back with a wheelbarrow. I figured out after a while there was no reason to be careful with them -- even rudely dumping the load on the ground never broke any of them. Try that with bricks.We used "landscape fabric" (the 12' wide unrippable tough stuff), 6-8" of 21A gravel (a mix of gravel and stone dust) wet compacted hard as a basketball court, with a 1" bedding layer of sand. No problems. Settings the stones was really fast.The surface drainage is good, and it also does absorb water like a dry well -- just very slowly. Still beats the rate our clay soild takes water.

5. 
   Guest_ | Apr 07, 2000 08:04am | #18

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   I am replacing a deck on my house. Traditionally I would just design and construct a wood deck even though it is nearly at ground level. No big deal here. BUT, I wonder if laying a concrete slab covered with something like pavers or brick would work too. I don't like a plain concrete slab because it is too drab and lacks class. After all this is Fine Homebuilding. None of the local cement guys is interested in doing a decorative slab so it is up to me to finish.

   My idea is to do this once and then not having to touch it ever. With wood I will have to maintain it and probably replace it in my lifetime. Since I'm getting lazier with age I would like to avoid that.

   Good idea? Problems? Alternatives?

1. 
   Guest_ | Apr 04, 2000 02:00am | #1

   *Hi FredBWhy not eliminate the concrete slab idea and intall the pavers or bricks over a bed of compacted sand?Build a border of wood railway ties or form a concrete curb around the perimeter if you require a build up and fill in the area with the product of your choice.Cheaper and will lasts just as long.Chat later,Gabe

1. 
   Guest_ | Apr 04, 2000 05:10am | #2

   *The homeowner, my wife, says no. She wants to convert the deck that is nearly at ground level to something fancier than a slab. But, she has rejected pavers in sand. The customer rules.So, now I need to come up with something else that looks good, will withstand freezing and will last.

1. 
   Guest_ | Apr 04, 2000 05:30am | #3

   *Your main consideration is to get the deck to the elevation you want and then make it look attractive.Besides the RR ties with backfill mentioned, the other best option is a poured slab. You can go with stamped concrete finish of multihued colors--approx. $6/SF if done by other--red brick over slab, or some type of paver or stone over the slab. Another option is to pour the slab, let it cure, then acid wash with various colors for a transparent, pearlessence sheen to the otherwise drab slab. Look in the archives for more information.

1. 
   Guest_ | Apr 04, 2000 06:18pm | #4

   *Why reject pavers on sand if pavers on concrete is acceptable? It seems like they would look the same when finished (Gabe suggests a way to raise it, if that is desired, from grade).One big reason why not to put pavers over concrete is frost heave (if you live in a frost prone area). In Michigan, if you put pavers over concrete you'll get the whole job to do over again in about 10 years (the post office in Ann Arbor had to totally re-do their entire landscaping due to this). The purpose of the sand is to drain. The concrete will drain but more slowly, presumably too slowly.

2. 
   Guest_ | Apr 04, 2000 06:30pm | #5

   *Am I missing something here? Pavers on a slab = ok; Pavers on sand = no? If she doesn't like the look of pavers it doesn't matter what's underneath, right? Or does she want them set with motar joints in between?How about this. You're a contractor, so money's no object right? How about a slab with bluestone, flagstone or slate tile on top? Just an idea.You can get her mind off the deck idea when you tell her about all the critters that'll be lining up to make the space underneath their new home. The first time you have to pull up deck boards to fish out a bloated dead opposum you'll be ordering up that 15 yard dumpster to haul the rest of the deck off!Need more info to advise you any further, such as preferences and concrete finishing skill level. Colored surface hardeners can be mixed and troweled in for various affects. Rent a walk-behind saw to cut patterns in the surface and it can look like an expensive tile job when you're through.Eric

3. 
   Guest_ | Apr 04, 2000 10:19pm | #6

   *Thanks guys. She has decided to follow my advise so it will probably end up being pavers in sand. It wasn't the look of pavers she objected to. It was the idea she had gotten from somewhere that anything in sand was an inferior installation vs installing over concrete. You may know how it is: Even Jesus wasn't listened to in his home town.

4. 
   Bearmon_ | Apr 05, 2000 12:09am | #7

   *FredB, what climate are you in?

5. 
   Guest_ | Apr 05, 2000 03:33am | #8

   *Well, hush my mouth. You boys mention something I never considered--frost heaving. Out here, we don't think about it much. I'll try to remember this for next time.

6. 
   Guest_ | Apr 05, 2000 03:45am | #9

   *Hey bearmon, fancy meeting you here.FredB- I don't know how to post a link yet, but check out the thread "It's paver time". Alot of good input about how to lay the pavers, but do it in gravel not sand. You will be happier.If you are going to set the pavers on a slab, then do it with a pretty dry mud. Something that will hold it shape when you squeeze it in you hand. Then tamp level like you would with sand. Dip you pavers in a cement juice. Just water and cement, real runny. Set the pavers on the still wet concrete and tap till level. Grout with cement and sand mortar. This will crack and heave. If you want lifespan, go with the gravel bed.Scott