View Full Version : here we go again!

06-23-2002, 10:38 PM

A few weeks ago I had posted about a job involving a concrete pool patio that needed to be overlayed with pavers. Well, about a day after I finished that job, I got another call.

Guess what. This time, its 3 patios that are already poured concrete that the people want done in pavers.

I was just at the job today, and got a good look at the job. It consists of 3 main patios, 1 large area about 2000 sq feet, and two smaller ones about 600 sq feet ea. All are already ROUGH finished concrete.

The homeowner was going to use natural flag stone in concrete, but now that the project is coming into its final stages and the budget is starting to be a concern, they are thinking pavers to cut some costs.

Not sure what exactly to do yet on this one. The concrete was poured rough because it was initially planned to be covered with the wet layed flag. Very bumpy, so I'm gonna have to screed something over it to smooth it out.

My first question is how much dust would you think you could put under the pavers/on top of the concrete? I may have to bring it up a bit to meet the door sill (almost 3 inches) and trying to predict any problems with having that much dust sitting on concrete/under the pavers.

Next is drainage. For two of the patios, I can drill holes into the footing, fill with small pea gravel, then cover with fabric and hopefully get drainage out of it. The big problem is the third patio............its elevated above the 2nd one coming out of the second story......not sure what to do with this one yet.

I talked with the builder today, and he thought we should maybe bring a mason in to pour a level base of concrete over the rough base already to both bring them up to grade and to give a smooth surface to maybe just bond the pavers directly too. I said if we do that, we might as well just wet lay them into that layer. However, for some reason, they don't want to do that.

If your out there Paul, I remember a while back you posted about a parking garage where you were going to overlay concrete with pavers.

You mentioned screeding sand to a thickness of 3/8 and then compacting to 1/4 inch.......one question, how do you screed sand that thin? and how do you compact it?

Any input greatly appreciated. Will try and get some pics up in a few days. Big time problem here too, as the people want it done NOW (as always) A very, very high end home, so I want to be on the ball here.


06-24-2002, 06:14 AM

How did the other one turn out?

These high end people often get freaked out near the end of construction. If you give them a good explanation why it needs to be done a certain way, they come around. Even the really dominant personalities adjust to sensibility. If it needs to be wet laid, why compromise your standards or risk having problems to penny pinch for someone that will still have money for a lawyer when you are through?
I'd tell them that you can not justify Mickey Mousing something just to make a buck. They will respect you and ask themselves the same question. They will do it right if pushed and they will respect you for it.
You will not make high end your usual customer base (assuming you want to do that) unless you only do it right and be very bold in telling them that you only do it right.

06-24-2002, 12:34 PM
Why not rip up all that concrete.??? Thats what i'd do.. i tell them listen... i don't like puttin pavers over concrete, there is gonna be too much prep work in getting this bumpy concrete how we need it to lay pavers, it may make sense just to rip it all up.... I'd rather get a dumpster and rip up all this concrete, and put my own base down and do the pavers the way i like to do them, i'd tell the homeowner, or is riping up that concrete too much work for u?... (for me it wouldnt be because i got the equip.) dont know what to tell you... it sounds like a nice paver job none the less....

06-24-2002, 09:05 PM

talked to unilok today (that is the paver being used). They said that drilling holes, covering with fabric, and using up to 2" of dust will work and that it won't void the warranty on their products.

what was interesting was what they had to say about adhering bricks to concrete or even wet-laying their products............I just want to say that these people are brain washed beyond belief.

I mentioned that I may wet lay the bricks. They said NO. I said why not? They said because the concrete will crack and that the bricks will then crack. I said ok, so if a mason contractor wet lays flag stone on top of the concrete, they are going to crack too, and that isn't it odd that people have been installing stone this way for hundreds of years. They said nothing, but then repeated the fact that laying the pavers wet will void the pavers warranty, and for that matter, adhering the pavers to concrete will also void the warranty.....I then asked if it was ok to adhere their pavers to their concrete blocks.......they of course said yes..........I said, 'aren't the blocks concrete though, and doesn't that void the warranty'............they got very snooty at this point......lol.

Not for nothing, but this really is a racket. Let me ask one question.........Are paver installation guidelines set-up to ensure proper installation, or are they set up to protect paver manufacturers?

I think you know my answer now, but would like to hear a few responses.


06-24-2002, 10:13 PM
I've been following this thread but was reluctant to post because I had received the same warnings from Unilock that Steve last posted. I've lost a couple jobs because of their warnings, but have also seen the product laid over concrete.

What I did in one case was to glue the perimeter bricks in place and dry lay the center, then glue the sides on as well. I told the customer that I couldn't warranty that part of the job as it was against Unilock policy and they were OK with that. To date, 2 years later, the only problem has been one of the glued perimeter bricks has come loose, I just re-glued it. I'm curious how you'll make out, I have a job that I had declined in the past I might reconsider. Sure makes for easy prep work!

06-25-2002, 05:58 PM
Yet another twist..........

Now the builder of the house is saying that he wants the pavers around the pool (another part of the project) to be set on concrete because he doesn't want them settling.

This is getting interesting. Quite honestly, I don't see it as being that bad of a idea because as we all now, new pools are areas prone to settling. The only twist here is that the pool was sprayed in.......therefore, they did no backfilling, just dug the hole, shaped it, and sprayed in the gunite. So technically, there shouldn't be any settling, but I guess if you think about it, a concrete slab would be a insurance policy.

Everyday its something new!

I think what I am really looking for in this post is someone to tell me that they have seen, or they have actually had an experiance where pavers were on top of concrete and they failed miserably. I have yet to hear any stories, and as Pelican so politely mentioned, he has had good experiences. So lets put all this manufacturer 'approved' thought processes aside, and tell me what 'really' happens when pavers are on top of concrete, not what 'in theory' happens.


06-29-2002, 10:30 PM
Steve sorry for the delay, we used 3/8" ground rods as screed rails. Compaction was done after the bricks are laid.

As far as pavers set on concrete you shouldn't have any problem. But I don't like to set pavers in "mud". I would look at using a good epoxy glue for the edges, they have some very good ones now that allow you to set brick even if there is water around or on the surface.

I recall a few years ago paver manufactors where allowing you to cut bricks down to install over stoops we have cut them as thin as 1/2" thick to prevent trip hazzards.

06-30-2002, 02:16 PM

I kind of figured you meant that you compacted the pavers and not the dust first, but wasn't sure. Thanks.

I still have tech guides describing how to 'veneer' pavers onto concrete by cutting them down in width to meet final grade. I have guide that shows 'approved' methods for redoing concrete stoops/steps on front of houses where they use adhsive on all of the blocks.

I don't like the idea of wet laying either........mainly because I don't do it and I don't make any money then!

What brand epoxy do you use. I used a brand that came in a regular style caulking tube that had a handle you pumped about thirty times to mix it and then just poped it out and use the build in nozzle in a regular caulking gun.......it worked good but time was critical.......lost a lot of epoxy as it was hardened in the bottom 3rd before I could use it.

How much time do the guns that mix it with the 'spiral' nozzles give you? Can you save unused epoxy in those tubes? I've used small guns, but they were very small tubes, and those you could just snap off the disposable nozzles, and then put a new one on when you wanted to use the rest.

Were gonna have to epoxy the stones around the border, so I'd like to get the epoxy and gun soon so I'm read to go.


06-30-2002, 05:02 PM
Steve, the glue I use is Liquid Nails Heavy Duty Construction Adhesive, I've had very good luck with it. My oldest jobs are 5 years and still holding. I've gone back to a job or two to make changes where the original job had to be dismantled and where I've used glue, the concrete pulls apart rather than the glue failing. It does seem to be moisture sensitive though, it doesn't bond real well to wet areas.

I don't doubt that epoxy might be stronger, but it's much more tempermental as you've stated.

07-01-2002, 08:23 PM
We use a couple of different epoxies, one is a double tube that needs a special gun and replacment tips (tips cost a buck apiece) but the glue is good for all day or the next month. One other we use is a two part mix that can be troweled on with a notched trowel ( we use 3/8" or 1/4") set up time is 4 hours once troweled on but can "heat up" if too much is mixed at one time.

As far as brand names that I will have a hard time with, I call my local construction supply house for the best one for the type of job we are doing.

The real trick with pavers that you have to remember is to glue the joining brick together, near the end of the brick about 1/2" in. This allows sand to be swept into the joints and stay there, no wash out this way.

07-07-2002, 12:50 AM
I've been thinking about this thread a lot, and just realized something:

Unilock provides plans for BBQs and pillars built with their product where they instruct you to glue the blocks together. They also instruct us to glue the coping on the Pisa II. Why is it any different to glue the bricks to concrete? Granted, the poured concrete isn't compressed like the bricks, but how can this process harm the Unilock product and what is the reason for voiding the warranty?

Things that make you go Hmmmmm....

07-07-2002, 11:06 AM
I'm currently doing a job that involves a short wall 10 1/2" thick. The snafu is that it's exposed on both sides and has to have split faces showing each side. I'm using Techo-Bloc Mini-Creta which I'm sawing into units rpoughly 4 and 6 inches deep and alternating sizes by course to get some sort of tie together. Using adhesive everywhere blocks touch and filled the bottom courses with aerosol foam to try to keep water from getting in there and freezing. I'm not sure the adhesive will stand up to extreme freeze pressures if water sets in the part that is below grade. Other than being slow it seems to be going together OK. I did pour a thin footing so I didn't have to fight so much with the small blocks to get that first course set true.

07-07-2002, 04:51 PM

EPHenry now has a double sided wall - (Coventry wall) I believe.

It has been requested a lot around here and is now available.

Also, this company gives very low cost ICPI courses in the winter months. You can get certified in pavers, steps, walls, etc. They also give demonstrations for installing over concrete and/or asphalt.


07-07-2002, 07:03 PM
There's no doubt that uni-lok is going to not say its alright to glue their product.......if they did, they would be shooting themselves in the foot.

What I don't get is this............all these retaining walls are 'flexible systems', or in other words they move. Manufactures all suggest glueing cap stones to the top..........If you ask me, glueing anything to a 'flexible' wall is much more prone to crack due to movements in the ground than gluing pavers to a 8" steel reinforced pad of concrete.

Not for nothing, but I've never really bought into this ICPI thing for one simple reason.......it has nothing to do with the way you do your work........

Anyone can go take a ICPI class and get certified. All you need is a check to pay for it and your in........

I know way to many guys that are ICPI ceritified who do **** work. Not to say I don't believe in the underlying idea of ICPI, I just believe it really is no way to say one contractor is better than another because of the certification..


07-07-2002, 07:21 PM
One thing you have to remember about gluing pavers or wall cap, the manufactures recommend a flexible glue! No they do not recomend epoxy, most are going to recommend their brand of glue. Before the adhesives they market now the only thing used and recommended on walls was butyl rubber tape, a messy very non-secure system.

We use epoxy, because it holds better than any other glue under very demanding conditions.

07-07-2002, 08:50 PM
I'm sure you're all aware of Unilock's cartridge type glue, I mentioned the Liquid Nails earlier because I find it to look the same, smell the same, (no, I haven't tasted it) as what Unilock sells at 1/3 the cost.

If you ask me, glueing anything to a 'flexible' wall is much more prone to crack due to movements in the ground than gluing pavers to a 8" steel reinforced pad of concrete.

I agree 100%.

Gluing each brick must be extremely time consuming though, and costly as far as the glue is concerned. Have you come up with a way to speed the process?

07-07-2002, 09:32 PM
I noticed a few mentions of "why is it ok to glue to concrete wallstone but not concrete?" referring to Unilock.

Poured concrete is not the same as concrete pavers or concrete wallstone. They are manufactured under extreme pressure with low moisture content.

I don't see how wet laying them should void the warranty. The poured concrete may crack, but the pavers will be able to take the stress no problem.

Although there are times that laying pavers on top of cement is the only way it can be done, in this case it isn't the only way. They could remove the cement and do it the right way. They should remove the cement and do it the right way. The only reason they don't want to is because it makes all the money that went into the cement a mistake. But it would be a bigger mistake to lay the paver on the cement when it could be done right.

Why do we install so many pavers to begin with? Because cement will crack and shift. So glueing pavers on top of cement is just going to make it harder to fix when the cement does crack and shift. But then it may be 10 years from now and the current owners may not even live there any longer, so who cares.

I have to go along with AGLA on this one. Tell them that the concrete gets removed and the pavers get layed correctly, or you won't do it. It would be hard for me to walk away from a job that size, but I would walk. If it doesn't turn out good, or the homeowner just "doesn't like" it, guess whos fault it will be. And if it went to a lawsuit, guess which side Unilock would be standing on.

If you ask me, glueing anything to a 'flexible' wall is much more prone to crack due to movements in the ground than gluing pavers to a 8" steel reinforced pad of concrete. The pavers aren't gonna crack, so that isn't a concern. And as far as the "flexible" wall goes. The glue is flexible as well....
Now if you were to cement the caps on... then you're gonna get some cracks.

07-07-2002, 10:56 PM
Now if you were to cement the caps on... then you're gonna get some cracks.
This is how Unilock specifies the coping is to be attached to the Pisa II, per their training seminars and literature.

07-07-2002, 11:55 PM
With cement? I don't think so.

This is from their website: "Coping units are used to finish off the top of the wall. They are glued in place with Unilock® Adhesive."

07-08-2002, 01:59 AM
Steveair, if the only way to do this job is to leave the concrete in, then do this. Use a 8 CM paver as a border and a 6 CM as your field it should give you enough room to screed out a base under the the smaller pavers and allow you to glue down the border pavers.

Looking over the responses here I see not many have done bridge decks, or road installations. Setting pavers over concrete or other road base material is done offen on bigger jobs where heavy traffic is to be expected, or used as a wear strip. As a replaceable surface paver have a longer life than most surfaces and can easily be repaired by unskilled labor.

I see no real problems with setting pavers on concrete especially a patio that that will see little heavy traffic. Factors such as proper pitch and drainage can be handled with out too much trouble, you might have to use a coping from a wall unit or even a solid wall unit to adjust the height of the patio and use sand of stone dust to make it work.

As far as cracks showing up in the product that can be prevented by using a fabric under the sand or dust and gluing it down, this will support the paver if small cracks appear in the near future.

All in all this is a very doable that should make you some money and add to your skills.

07-08-2002, 09:17 AM
Steveair, if the only way to do this job is to leave the concrete in, then do this.It isn't the only way. This isn't a bridge deck. A bridge deck WOULD be one of those times that it isn't an option. If you put them over concrete in this yard simply because the homeowner or builder "doesn't want" to remove it, why even bother ever removing concrete.

"No problem, will just put them right on top of your old cracking driveway, it'll save you some money." :rolleyes:

07-08-2002, 04:26 PM
If cost is a factor then it might be the only way, tear out might bring the cost closer to natural stone that was planned for in the first place. The concrete is in good condition why take it out? An old driveway is a completly different story along with an old patio that seen it's better days.

Why do we install pavers on a gravel base anyway?? Because it's cheaper! Just like I know we all test our base so we've achived 95% compaction along with soil tests, so we know that it won't move for 100 years. LOL

We are contractors, people ask us to come up with ideas that will fix an imperfect world. Engineers can tell us how to do a job under perfect conditions, but we have to deal with what builders, homeowners and Landscape Architects give us.

If you think its wrong to install pavers on a bridge deck, or a heavly traveled town square, maybe I should give back all that money I've made doing it.

07-08-2002, 06:42 PM

I got some pics the other day and posted them here:


I think this should help clarify this whole matter a little bit.

Plain and simple, I'm not walking away from this job. The pavers are going on top of concrete. If you say you wouldn't do it, that's fine, because I sure will!

Paul, were basically following the advice you just gave with the thinnner in the middle, thicker on the edge idea. A mason is mortaring sandstoe coping around the perimeter of each patio and setting the grade high enough to allow a paver and some dust underneath.

By the way, I love the pool at this place....I can't wait to see the thing when were finished.


07-08-2002, 06:47 PM
If cost is a factor then it might be the only way, ... The cost to remove it isn't gonna be that much. It's not like removing a bridge.:rolleyes: And besides, how much additional cost will there be in glue, labor (it's gonna take longer) etc. That makes removing it even less expensive.

Not to mention that you are on a website viewed by thousands of people saying that it's ok to install pavers the wrong way. :eek: Just do what they ask for and take the money huh?

Why do we install pavers on a gravel base anyway?? Because it's cheaper! Wow, I thought it was 'cause that's how professionals do it.

07-08-2002, 06:51 PM

I will say it is kind of like removing a bridge at this point.......look at the pics and you'll see.

I don't think its anyone's fault for jumping to judgements here. I think without seeing the job, its hard to really understand. After seeing it, the answer should be clearer.


07-08-2002, 07:20 PM
People have been mortaring stone into place for thousnads of year. Pavers are set on gravel base because it's cheaper, you use less skilled labor than a union mason, no need for mixers and helpers, no waiting for cement to harden, so on the whole yes thats why we do it on gravel base.

As for people veiwing this post and saying that I'm telling them the wrong way, for the type of job described here I don't think so!

Maybe I should learn the right way, do you hold classes?

07-08-2002, 08:23 PM
Well I Have been reading about this paver job and want to know when these classes are going to be held?

07-08-2002, 09:59 PM
Originally posted by LAWNGODFATHER
Well I Have been reading about this paver job and want to know when these classes are going to be held?

Answer: Pennsauken NJ at the EXPO center in February 2003

goto www.EPHenry.com


07-08-2002, 10:11 PM
Steveair, I looked at the pictures, but the only cement I saw was the patio against the house. The one with a stone face. When it's all done, post some more pics. And let us all know if they ran out of money before paying you. It's hard to believe that the cost of natural stone would be more than a drop in the bucket in comparison to the house. Good luck, sincerely.


People have been mortaring stone into place for thousnads of year. People used to comunicate by writing on cave walls also. But we are in a new millenium. Things change. Did they use expansion joints a thousand years ago?

Maybe I should learn the right way, do you hold classes? It's funny you ask, as a matter of fact, I used to teach classes every Saturday morning at 10am for about 4 years at a landscape supply yard. I also personally know 100s of landscape contractors, I've been to their job sites and have seen their work. And the one thing that I have learned, is that only about 10% of them do quality work good enough for me to recommend to anyone. I'm not saying that only that 10% install correctly, but overall quality is not that good. I've seen completed jobs with chipped and/or defective pavers that never should have been taken off the pallet. I've seen herring bone, basket weave, etc, patterns that did not have straight lines. Do the customers complain? Not always, but they don't know any better. And the customers that do complain are viewed as being anal. Is it the contractors fault, yes. Even though it was probably done by some "less skilled" laborers that only care about the paycheck at the end of the week.

stepping off my soap box I am not trying to rip on anyone here. I didn't see the job till the pics were posted, and it's hard to determine the particulars from pictures. We all know that the "ideal" method would be to remove the concrete. And we all know that in a few cases that is not an option. This may be one of those cases. I don't think it is, but we all draw the line at different points. And there is only one person here that has all the facts and has seen the job in person. Can it be done, yes. Will it look outstanding, probably. Will it pass the test of time, only time will tell.

If it were me, I would charge the same as if I were removing the concrete, or darn close to it, to make up for all their poor planning that you now have to deal with.

08-08-2002, 08:58 PM
Hello all,

was able to get some of the patios done on the house during the past couple weeks and figured I'd post a few pics.



08-08-2002, 09:32 PM
Looks very good my freind.

Looks just like it would have from the start.

Keep up the good work steveair!!!:D

08-08-2002, 11:36 PM
Might not be a bridge deck but it sure looks nice! Great work Steve!