Introduction: Concrete Octagonal Driveway Pavers
I had a problem.
I had this squalid little section of property on the far side of my driveway. Nothing would grow there, and the dirt was mounded up a foot above my driveway, so not only would it prevent drainage when it rained, the run-off would leave silt deposits in my driveway deep enough to plant corn in. This elevation difference also prevented me from parking anything there.
Pouring more concrete slab would've been costly, and simply scraping the plot level with the driveway and covering it with loose aggregate, like gravel, wouldn't have worked, as I have an inward slope on my property.
So I settled on the idea of doing one of those "waffle driveways" that I'd seen before in older neighborhoods - I could park stuff on it - it would be cheaper than slab - and it would, if not solve, then greatly ameliorate the drainage problem as well.
As it turns out, the commercially available "waffle driveway" pavers weren't all that cheap after all - if I had used them, it would've cost me around $800 to get the coverage I needed.
I didn't need much more convincing than that to decide to make the octagonal pavers myself. Some quick guesstimates gave me a figure of ~$200 worth of concrete needed... Game on...
Step 1: Getting the Ball Rolling...
I would be needing quite a few of these pavers, which necessitated making them in batches. in order to do this, I would need something large and sturdy in which to mix the concrete. Wheelbarrows and shovels do the job pretty good.
This project can, of course be scaled down. If you only have the capacity (or need) to make a few, you can mix small batches of concrete in a bucket with a garden trowel. I wouldn't recommend a common five gallon bucket for mixing concrete, as it is too deep and narrow to be able to thoroughly mix the concrete - it's not impossible if it's all you have, but a better option would be something like a dollar store rectangular dish tub, or a bus tub from a restaurant (I'm not telling you to go steal a bus tub from a restaurant, but that would make for a pretty funny criminal record if you did...)
I would also need to make several identical concrete molds - having access to certain power tools made this task much easier. A miter saw, and drill with bits and drivers (pictured) will be needed to construct the molds. The drill is a pretty easy get, but not everyone is going to have the room or the budget for a huge electric miter saw. If you only want to build one mold, you could get by with using a miter box and miter handsaw Be aware that this project calls for 2x4's, and not all hand miter boxes are big enough to handle wood that thick.
Cured concrete can be a bit challenging to remove from the molds sometimes, so a hammer comes in handy when you need to gently knock a paver loose from the mold. The three pound "persuader" in the picture (with yellow handle) should really only be viewed as an option of last resort, but its nice to have around...
Step 2: the Concrete Molds
Here we see the design I settled on for the paver mold. Concrete is pretty grippy stuff when it cures, so it won't just pop out. That's why I chose to employ a clamshell design.
I did quite a bit of patterning beforehand - basically trying out different sizes before I decided to commit to anything. In the end, I went with a roughly 8 inch wide paver. The great part about doing this yourself is that you get to decide how big your pavers should be - just remember, the length of each of the eight sides, and also the length of the inner sides (of the hole in the middle) should all be the same - in my case all the outer and inner sides of the pavers are 4 inches.
The three piece inner mold assembly consists of a piece of 4 inch 2x4 (in the middle) and (2) 4 inch pieces of 1x6. this design wasn't my first attempt - but rather was the result of a "live and learn" experience - which I will divulge the details of later in this instructable...
knowledgeable carpenters will recognize that 2x4's aren't really 2 inches by 4 inches and 1x6's aren't really 1x6 - so I won't come up with exactly four inches on all sides... But I just went with it anyway - the difference is a fraction of an inch, and isn't actually noticeable. If my laissez faire approach to this project triggers you, please feel free to make your own pavers to more exacting specifications...
Step 3: A Little Woodworking
As you can see in the primitive caveman drawing I've posted, the mold consists of four bevel cut 2x4's, two straight cut 2x4's (4 inches long) and four straight cut 2x4's (2 inches long) - as well as a buckle and hinge. screws and glue hold the whole thing together.
If you plan on making multiple molds, I would suggest using an assembly line approach like I did - make all of the bevel cut pieces, then all of the straight cut pieces, before assembly of the molds themselves. This way you don't have to keep re-setting the angles on your miter saw - and assembling the molds from a "parts bin" of randomized components ensures a level of consistency among the molds - good or bad, at least they'll all be the same...
In order to hold the whole thing together while I assembled it, I used a ratcheting cargo tie-down. When securing all the pieces together for final assembly, take the time to ensure that all the inside faces of the mold are angled properly, that all the adjoining faces are flat and flush with one another, and that the inside corners are as uniform and flush as you can get them. You may not achieve perfection (I certainly didn't) but extra time and effort does pay off...
In addition to glue, I used 2 inch deck screws, driven in diagonally, to secure the individual components together. Starting from the "top" (the molds don't really have a top or bottom) I sank a small pilot hole diagonally down through the beveled pieces into the straight-cut pieces, then I chased the pilot hole with a hole large enough to countersink the screw heads, but only about a 1/4 inch deep. When working close to the edges of relatively cheap wood such as this, pilot holes are imperative - as you will split the wood wide open if you attempt to just "brute force" the screw through...
Once I've gone all the way around the mold with screws on one side, I flip it over and repeat the process.
A quick note on pilot holes - the hole, ideally, should be just a hair smaller than the shaft of the screw you plan on using. One way to ascertain this is to take the bit you plan on using and hold it directly behind the one of the screws, if you can see the bit peeking out from around the screw shaft, then the bit is too big. now reverse the screw and bit, all you should see of the screw is the "spirals" - and maybe a tiny bit of the shaft - if you can see a lot of the shaft, then the bit is probably too small.
Step 4: Preparing the Molds
Almost time to start pouring concrete!
The pavers need to be smooth on one side. To achieve this, I experimented with a few different kinds of underlaying material. Plastic (coroplast) didn't allow for water dissipation in the curing concrete - though it did produce a super smooth face on the paver. I also tried just setting the molds right on the treated concrete floor of my garage - this also produced a pretty smooth face, but left a nasty residue on my garage floor - and I encountered the same water dissipation problem that occurred with the plastic.
So after I was done attempting to re-invent the wheel, I settled on a spare piece of plywood. The professionals who pour sidewalks and driveways for a living use wood forms - and since they probably know more about concrete than I do, I might just be well served by following their lead...
Not surprisingly, the wood turns out to be a decent choice... It allows for water dissipation, releases from the cured concrete fairly easily, and provides a pretty smooth face, too...
In order to correctly place the center molds relative to the outer mold, I created a crude centering jig. It worked fine, but I soon discovered that I couldn't tell the difference between finished pavers with jig-centered molds and pavers where I just eyeballed it... After that, the centering jig fell into disuse... If you're careful, eyeballing the center mold placement will work just fine, and you shouldn't need a centering jig - but ultimately it's your call...
If you look closely at the fourth picture, you'll notice that some of the center molds are wrapped in different materials - I was experimenting with ways to make releasing the center mold less traumatic. Leaving the center mold exposed to the curing concrete made for a few instances in which a significant amount of force had to be used to release the center mold - this occasionally resulted in damage to the finished paver, or the mold itself.
My experiments showed that the material which worked best was that scratchy brown paper towel commonly found in gas station bathrooms - held in place with a bit of masking tape... Newspaper worked pretty good too (I tried plastic kitchen wrap, but that was no good - water dissipation again)...
As long as the concrete particles can't get into the fiber of the wood, it won't stick... In fact, punching the center molds out after I began using the paper towel became so easy and painless that oftentimes I could use my hands - pushing the center block out gently through the bottom and just pulling the sides blocks up through the top.
Step 5: Let's Make Some Pavers!
Now we can finally get to the fun part!
(As soon as we make a few decisions...)
what kind of concrete (general use, high strength, fast curing)?
how thick should they be?
how should they be reinforced?
If the area you plan on covering is going to see mainly foot traffic or very light vehicle traffic (bicycle, motorcycle) then general use concrete with relatively light reinforcement (such as shown in the picture) will be adequate.
My pavers were going to be seeing a bit more abuse than that (motorcycles, light cars, light trailer) but they wouldn't be in a high traffic area - it would be more like spare parking - so I chose to use high strength concrete with a light reinforcement (I was really just being lazy here - heavier grade rebar isn't going to do any harm, but it would've meant more work...)
I actually tried out several different reinforcing options (by "tried out" I mean I smashed a few pavers to smithereens...) The heavier grade metal wire didn't seem to impart any more strength to the paver than the skinny wire seen in the pictures, So I didn't see the point in using it... The thick rebar used in larger concrete jobs would've been nearly impossible to bend into the tight circles I needed, so that was out of the question. To create those tight circles with the 16 gauge wire, I used a small bucket as a form to wrap a length of the wire into a circle of the appropriate size. I then twisted the ends together to form a loop.
Those of you desiring a paver that can be used in a heavy vehicle, high traffic area should probably use high strength concrete with heavier rebar. Your pavers should probably be a bit thicker than mine too...
Which brings me to another belabored, long-winded point; there are many variables that will affect the quality of the finished paver - variations in thickness will have a profound effect in the overall strength of the paver. The solution may seem like a no-brainer; just make 'em all as thick as possible... No one will stop you if that's how you want to play this, but I didn't want to waste a lot of concrete, and I didn't want to bust my back with massively heavy pavers.
After yet more experimenting, I decided that pouring the molds roughly 2/3 full gave me a thickness (~3 inches) I was comfortable with. Conveniently, it just so happens that a sixty pound bag of concrete makes just enough to fill six molds to the correct depth - and an eighty pound bag will do so with eight molds. Easy to remember.
When pouring the concrete into the molds, you should stop about halfway to tamp the concrete down into the mold (I used some scrap wood) and to place the reinforcement wire (or rebar). Then pour the remaining concrete. Tamp down the concrete once again, with an eye towards making sure the concrete is level across the mold - I mention this only because I had a few pavers turn out wedge shaped - due to my lack of attention to this detail.
If you're doing a small scale version of this project, you could weigh out ten pounds of dry concrete mix at a time for individual pavers. If you're doing a handful of pavers one at a time, you could weigh it out once, and then put the weighed mix in a bucket, mark the fill level of the bucket, and then just scoop out the mix to that level for all subsequent pavers. You should use a dust-mask or a t-shirt wrapped around your face when messing with dry concrete mix - for god's sake, whatever you do don't breathe the shit. You'll die. Probably.
As you can see in the pictures, I also think it's a good idea to wear gloves when working with wet concrete, it's not actually that hard to wash off, but it will suck all the moisture right out of your skin. If you're only doing a few pavers then it isn't such a big deal - but I did around 40 batches of six or eight at a time, and my cuticles began to crack...
A final note about mixing concrete; the amount of water used in the concrete mix will determine the consistency and strength of your final product - too much water will make for brittle concrete, and too little water makes crumbly, air pocketed concrete. Following the manufacturers recommendations is a good start, but you may find that you have to throttle the water/mix ratio a bit in order to find the butter zone - if you're unsure, play around with small batches first - this will help give you an idea of what the proper consistency should be...
Step 6: De-moldng
Oooh... It got hard...
which is more or less what I expected would happen... I've patiently left the curing concrete alone for 24 hours - and now is a good time to release the new pavers from the molds - any sooner and the concrete won't be cured enough (and it will be crumbly). Any later, and the concrete tends to get overly fond of the wood molds, and I have trouble separating them. Once out of the mold, it's a good idea to let the new pavers continue to cure for a few days before use.
On the topic of the three piece inner mold; My first attempts at making these pavers were met with poor results, due to the fact that I had tried to use a single 4x4 piece of wood. The force necessary to overcome the wood/concrete friction (and remove the mold) proved inevitably destructive to both paver and mold... The three piece set up allows me to remove the center block first - which makes room for the side blocks to collapse into - reducing friction by reducing the amount of wood/concrete contact area in motion at any one time (I hope that made sense).
I'm sure there are plenty of other clever ways to resolve this dilemma, but this worked well for me - and when combined with the paper towel wrapping mentioned earlier, the center mold becomes easy enough for a child to remove.
Despite all my precautions, my defect/breakage rate was about 10% of the entire run - put another way, about half of all my batches either had a defective paver or I broke one...
Friction is less of an issue with the outer molds. The longer the drying pavers are left in the mold, the clingier they become - but if you remove them at the appropriate time, they should just slide out of the mold without much drama. Occasionally, you might need to lightly tap the mold until it releases. If you find yourself beating the crap out of the outer molds, you're probably doing something wrong... Whatever you do, don't hit the paver itself! Tap the mold only...
This brings me to a point about the molds themselves; Mine got beat up - they all got loosy-goosy after about twenty rounds. I re-tightened the screws and continued on, but a few of the molds just didn't make it. The gentler you are with your molds, the more mileage you'll get out of them.
We're well on our way! We've got our first six pavers! Only 194 more to go...
(Oh, and I guess I should probably sweep my driveway...)
Step 7: The Sand and the Fury...
And so... The end game begins....
I had a problem. I, therefore, created a solution. now I must toss them into the pit together and cruelly force them to fight until a victor emerges...
In practical terms, this meant first re-locating a few cubic yards of dirt (by hand) to another project I had going on simultaneously in the back yard.
In order for the pavers to sit flush with the driveway, I actually had to dig to a depth of around 5-6 inches below the driveway - to accommodate the pavers, and the sand underneath them. The sand provides a support layer for the pavers, distributing the weight more evenly and making them less likely to crack. Underneath the sand is a layer of weed barrier fabric - this prevents weeds from taking root. Regardless of it's size, weed barrier and sand will extend the lifespan of your project.
When it comes to laying flat areas of bricks, pavers, flagstone, etc, there are established methods for ensuring the project turns out level and flat. little of that applies to my project, as I'd be laying my pavers up the side of a hill. So, in order to get the courses of pavers to follow the slope of the driveway, I messed around with several different complicated methods. But again, I discovered that eyeballing it produced indistinguishable results.
One last thing, make sure and cover up your unattended spare sand, or the neighborhood cats are liable to leave you some of their buried treasure...
Step 8: The Big Finish
In the last step, I extolled on the virtues of weed barrier fabric. Well, you may want to ignore that advice if you plan on backfilling the holes with dirt and letting the grass grow. This is a perfectly viable option, that will provide you with a lovely lawn/driveway hybrid (or, if you're a "glass half empty" kinda person, you'll have a driveway you have to mow...)
I personally wasn't interested in doing any more mowing - so I opted to backfill the holes with .5 - 1 inch native river stone - I've already put the stuff on other parts of my property, and I like the way it looks - so it was a lazy choice. It took about a half cubic yard to fill up all the little holes - having an incline helped - I just dumped the stone at the top of the hill and shoveled it down with a push-broom... A few stones will be resistant to your efforts, but don't sweat it - they'll find a hole to settle into after a few days...
And no, that's not paint...
I made the decision to stain the concrete pavers because I wanted them to match the existing (store bought) patio pavers in front of my gate. I feel lucky to have found a color that matched those pavers, because frankly, the color selection of concrete stain is limited... Staining them all at once provided evenness and consistency of color. the stain was kinda watery, so I was able to use a hand pumped sprayer (seen toward the top of driveway) to apply it - if you employ this method, be careful of overspray - 'cause that stain ain't comin off the sidewalk...
The last element in my design was the retaining wall. I felt it was a necessary addition since i didn't want large chunks of my neighbors yard eroding out onto my fresh new pavers. I won't bore you with the details of my little wall beyond saying that it goes down a foot beneath the level of the pavers, and is full to the brim with ACTUAL rebar (and not the wimpy wire I used in the pavers themselves.)
Someday in the future I plan on capping that retaining wall with bricks or flagstone or something - aahh, I'll figure it out when the time comes...
And thats pretty much where this project ends...
Since the paver have been installed, I've parked cars and trailers on it, and even occasionally backed my truck up onto them as well. I'm sure some of you might share my concern that the pavers aren't adequately reinforced to be able to hold up to heavy things like my truck, but they have seen several months of use now, and so far none of them have shifted or cracked. Nestling the pavers securely into their sand bed, and packing their little holes full of stones (or dirt and grass) contributes greatly to the overall strength of the installation - but as with every DIY project, failure is still a possibility. That's fine though, if a few pavers crack, I can always just make more to replace them!
I hope the information I've provided here will be helpful to those of you who've never done a project like this before - for years now, I've benefited from the wisdom of those of you here on Instructables with more knowledge and experience than I have - and I'm thrilled to be able to (hopefully) put some of that currency back into the community.
Thanks again for reading, and I look forward to your comments!
We have a be nice policy.
Please be positive and constructive.
hello sir that are normal grass ,here in belgium we also lay it for you garage, and we sow sports grass there,then you can also drive over with your car provided that your surface is strong
Apply oil to your mould It stops the concrete from sticking. any motor oil will do ( not diesel oil though) if you are using sump oil. It works for commercial jobs.
I would cut the molds to the desired thickness of the pavers. You can slightly overfill, then use screed board to trim to height. Every paver will match in height and won't be wedged.
There's also a plastic product called a grass paver. For heavy vehicles and regular use there are types that require that you lay down several inches of gravel, with sand on top of that before installing the grass pavers. For occasional use, there is a plastic product that comes on a roll, that you roll out on top of existing grass.
There's a fiber that you can add to your mix that will increase the strength of your concrete. It will look hairy, but then you can burn off the hairs with a torch. Or they will just decompose in sunlight. Also, if you use a zero slump mix, you can pull your forms off as soon as you pour your concrete. You can add color to your wet mix, and it will keep its color without fading pretty much forever. If your not going to plant grass in the cells, use a polyurethane pellet to fill the cells. Nothing will grow in it.
In spite of what previous commenters say, I wouldn't use anything greasy for easing demolding. Cement in water yields a caustic solution, which in turn dissolves fat, or even forms soap-like compounds. You don't want the caustic substances dissolved in the water which is contained by the concrete mix to be diverted from their hardening role. Rather, I'd lacquer or wax the molds - lacquer or wax are chemically inert, or at least don't interact chemically with the concrete mix. Of course, the oil won't penetrate deep into the concrete, to make the pavers completely fragile, but it will affect the surface that's in contact with the mold. Even if it looks OK initially, it will wear easier than if no oil was used, down to maybe a fraction of a millimeter.
That plastic does not allow water to run out of the poured concrete is actually a good thing - and you should stick with plastic. Curing is not drying, it's a chemical reaction which consumes water. If water leeches out of your poured concrete, it takes chemicals which are needed for the concrete to harden with it.
Make your plugs with a 1/4" taper. They will release more easily.
True, but if Mr. DIY doesn't have a sophisticated wood shop, the effort to cut taper into the plugs could result in serious injury.
I've seen some good tips on the demolding. There is a professional demolding fluid on the market, but for private use, diesel will probably be the best solution.
As for the rebar: Rebar isn't used to increase the strengt of the concrete. It's used to increase stretch resistance of the concrete. therefore it's always positioned on the side of the concrete where it would tend to bend outward.
Water dissipation is something you most certainly do not want while your concrete is curing. As the cement needs the water. Without it, your cement will remain to weak. However, to much water will also weaken your structure. Therefore you should also cover your structure to prevent evaporation.
You should use no more than about 40% water (water to cement ratio). Also you should know that in the beginning some of the water overkill will rise to the surface, as concrete is heavier than water. This is called "bleeding". If you should notice this you'd best get your trowel out and refinish your structure (as long as the concrete is still somewhat moldable).
The time you need before you can demold your project depends on how fluid your concrete and how fast your cement is. But I would recommend to wait at least a day for any concrete project before demolding. This is for a "CEM III" cement (contains a high percentage of granulated slag from the metal foundries. If you're using a "CEM I" cement (also known as Portland C cement), you kan probably demold after a couple of hours. This is a very fast (high strength) cement which is often used on structures that require a lot of strength and is mixed in with "CEM III" cement on cold winterdays, usually 25% on mild winterdays up to 50% on very cold days. This is to start the curing of the cement as Portland C produces more heat while curing. This heat aids the cement in curing faster, so you could see it as an accelerator.
Use some (old) motor oil brushed on the molds, and the concrete won't stick .
been doing that now for 50 odd years. Look up the term "slump" to get the proper consistency of the concrete mix...
and Webmasters: go back to black text .This grey on white is the worst fad you guy's have ever come up with! Very difficult to read!!
Could I use regular concrete blocks? I am 77, recently had heart surgery so all this making, etc might be beyond my abilities and I was wondering if I got someone to help me we could dig down enough for the concrete blocks and fill them in with gravel and some soil. I would like to plant thyme and other stepables in the holes.
i see no reason why not!
You did all this, and never learned about form oil?
early in the process i talked to guys who knew concrete - i also came here for advice - as per the advice i received, i tried several different form lubricants (deisel, vaseline ect) but they were too messy for my tastes. my intense desire to implement homegrown solutions to problems led me to the process which i've detailed above - i might've broken down and bought some form oil if i felt there was no other solution. thanks
You mentioned that the impetus for this project was the cost of buying the brick. Did you track the cost of your solution? Was it substantially cheaper?
I would like to install a truck friendly access to my side yard, but not go through the appeal process to get approval for another driveway. I like to get deliveries of firewood, wood chips and leaves but have had the trucks get mired down in mud if there has been rain.
since i wasnt charging myself to do this i did not account for my labor cost - but if i were to do that the cost of the project would've gone through he roof - the projects i engage in tend to be labor intensive... in terms of materials, i did save about $600
Did you track the cost of your solution? Was it substantially cheaper?
Only if his labor came in under minimum wage.
Water dissipation: what is this about?
What square footage did you cover for $200? Nice job, by the way.