Home & Garden

Can I install paver right above concrete block?

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  • Jul 30th, 2020 4:27 pm
[OP]
Newbie
Oct 31, 2016
38 posts
7 upvotes

Can I install paver right above concrete block?

Hi all, I am quite confused with retaining wall installation, I have checked lots of YouTube videos and websites about this but still not getting the clear answer.
1. Home Depot is selling concrete block like this https://www.homedepot.ca/product/oldcas ... 1000150633, does it matter what coping we use? After adding gravel into it, can we add normal paver for example unilock paver, on it directly? Or do we need specific coping for it?
2. Unilock is selling different wall for example https://unilock.com/product/stackstone-ontario/
If I am installing this wall stone, can I install normal paver on it directly? If not, do I have to use its matched coping?

Thanks a lot!
8 replies
Deal Addict
Jun 26, 2019
2003 posts
1734 upvotes
GTA
I'm a bit confused by your question;

If you build your wall with the concrete blocks, you can either parge the outside or cover it with some veneer stone to make it look better. For coping (capstone) you can choose really whatever you want as long as it fits ontop of the wall.

For the Unilock wall, you would just buy the wall stone and then you're off to the races. Most stone walls will allow a wide variety of coping to be placed on top of it.

No idea what your scope of work is, but if you're DIYing it, I would probably just go straight for a precast wall block. It's probably a lot easier and faster than concrete blocks + parging or veneer.

In regards to your last question, do you mean you're building a raised patio? Or are you just asking what you put on top of the wall to finish it? You could leave it bare, put on some coping, or whatever you want really.

Hope it helps, let us know your scope of work and we can probably be of more help.
[OP]
Newbie
Oct 31, 2016
38 posts
7 upvotes
SubjectivelyObjective wrote: I'm a bit confused by your question;

If you build your wall with the concrete blocks, you can either parge the outside or cover it with some veneer stone to make it look better. For coping (capstone) you can choose really whatever you want as long as it fits ontop of the wall.

For the Unilock wall, you would just buy the wall stone and then you're off to the races. Most stone walls will allow a wide variety of coping to be placed on top of it.

No idea what your scope of work is, but if you're DIYing it, I would probably just go straight for a precast wall block. It's probably a lot easier and faster than concrete blocks + parging or veneer.

In regards to your last question, do you mean you're building a raised patio? Or are you just asking what you put on top of the wall to finish it? You could leave it bare, put on some coping, or whatever you want really.

Hope it helps, let us know your scope of work and we can probably be of more help.
Thanks a lot SubjectivelyObjective.
Yes I am DIYing this patio, one side is having steep slope as you can see from the image (point 1), I am thinking to add a mini retaining wall at this corner and raise it a bit to level with point 2. Can I lay retaining wall just at this little portion (about 4 feet) to level it up? The concern is that when backfilling 4 inches crush run, between 2 and 1, there might be some points above the ground, which means the gravel will have to touch the fence, should I install retaining wall on this path as well?

Do you have any recommendations for the mini retaining wall? like Permacon, oaks or Unilock?
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Deal Addict
Dec 18, 2017
1339 posts
916 upvotes
London, On
The Home Depot ones are just regular cinder blocks used in industrial types of buildings. They are cheap enough and big enough you problably only need a single level of them to bring up the level you are looking at. You certainly can run a length of them along the fence line to level it up, not going to hurt anything, and it doesn't matter what they front finish is like because it will be against the fence. Then you turn the corner and go however far back towards your wagon to level that up, or even run them the whole way, into the ground if necessary, to give a solid front frame for your patio. Then depending on how high above the ground level they are along that front edge, you can either finish them off as the poster above says, or build the ground up in front of them or plant stuff to hide the blocks. I would say that corner at 1 is probably where the most exposure would be, assuming the yard is lower there than by the wagon. So if you put some kind of bush or hostas or something right there, that will hide the blocks. I would expect after a year or so you may have some settling in your patio right along the inside edge of where those cinder blocks are though.
Deal Addict
Jun 26, 2019
2003 posts
1734 upvotes
GTA
JeffHill wrote: Thanks a lot SubjectivelyObjective.
Yes I am DIYing this patio, one side is having steep slope as you can see from the image (point 1), I am thinking to add a mini retaining wall at this corner and raise it a bit to level with point 2. Can I lay retaining wall just at this little portion (about 4 feet) to level it up? The concern is that when backfilling 4 inches crush run, between 2 and 1, there might be some points above the ground, which means the gravel will have to touch the fence, should I install retaining wall on this path as well?

Do you have any recommendations for the mini retaining wall? like Permacon, oaks or Unilock?
Let's do some quick math here. Yay Math!

Anyways, assuming each section of fence is about 8ft, it looks like you have about a 20ft span on that one side you're going to cover. Based on the stepping down 2x4s, looks like you have two 4 inch step downs, plus another 4 inches to point one, so you have 12 inches total. All things considered, your patio run is over 20ft is probably only going to drop about 3 inches assuming around 1%, so you stil have 9 inches to make up?

So the question is, first, what are you doing between 1 and the wheel barrow? Is your plan to have a step down, or are you just going to grade the soil up to make it level? If you're having a step down then you would need a bit of wall across that whole side, but I assume you can raise the grade on there just as easily.

If your only concern is having a grade to high on the fence side, you could just either get concrete blocks (8 inches thick) or a retaining wall block (also probably at least 8 inches thick), make sure you bury them at least 6 inches deep, and then put the pavers right on top of them. Then you can use an adhesive to keep them in place. That should do the trick, and no one will see it and it should match the rest of the patio. The edge restraint isn't the best, but it should still hold fine. A proper edge restraint on the top of a wall would be a nice piece of coping, however these are sizable and probably going to run you $10-15 per linear foot, also you would have to carry the coping all the way around the patio to keep the look consistent, which gets expensive fast.

One other thing, is if its only a few inches, you could lower point 2 and raise point 1, and then use a precast curb along that side of the patio. Granted these things are not really designed to retain soil, but if its just 2 inches, should be fine.

Anyways, I hope you are sufficiently confused now.
[OP]
Newbie
Oct 31, 2016
38 posts
7 upvotes
djeffery wrote: The Home Depot ones are just regular cinder blocks used in industrial types of buildings. They are cheap enough and big enough you problably only need a single level of them to bring up the level you are looking at. You certainly can run a length of them along the fence line to level it up, not going to hurt anything, and it doesn't matter what they front finish is like because it will be against the fence. Then you turn the corner and go however far back towards your wagon to level that up, or even run them the whole way, into the ground if necessary, to give a solid front frame for your patio. Then depending on how high above the ground level they are along that front edge, you can either finish them off as the poster above says, or build the ground up in front of them or plant stuff to hide the blocks. I would say that corner at 1 is probably where the most exposure would be, assuming the yard is lower there than by the wagon. So if you put some kind of bush or hostas or something right there, that will hide the blocks. I would expect after a year or so you may have some settling in your patio right along the inside edge of where those cinder blocks are though.
Thanks a lot, that's great advice. If I run a length of them along the fence, should I install coping stone on top of those blocks? or maybe I can lay paver right on top of the blocks and then install edge restraint?
[OP]
Newbie
Oct 31, 2016
38 posts
7 upvotes
SubjectivelyObjective wrote: Let's do some quick math here. Yay Math!

Anyways, assuming each section of fence is about 8ft, it looks like you have about a 20ft span on that one side you're going to cover. Based on the stepping down 2x4s, looks like you have two 4 inch step downs, plus another 4 inches to point one, so you have 12 inches total. All things considered, your patio run is over 20ft is probably only going to drop about 3 inches assuming around 1%, so you stil have 9 inches to make up?

So the question is, first, what are you doing between 1 and the wheel barrow? Is your plan to have a step down, or are you just going to grade the soil up to make it level? If you're having a step down then you would need a bit of wall across that whole side, but I assume you can raise the grade on there just as easily.

If your only concern is having a grade to high on the fence side, you could just either get concrete blocks (8 inches thick) or a retaining wall block (also probably at least 8 inches thick), make sure you bury them at least 6 inches deep, and then put the pavers right on top of them. Then you can use an adhesive to keep them in place. That should do the trick, and no one will see it and it should match the rest of the patio. The edge restraint isn't the best, but it should still hold fine. A proper edge restraint on the top of a wall would be a nice piece of coping, however these are sizable and probably going to run you $10-15 per linear foot, also you would have to carry the coping all the way around the patio to keep the look consistent, which gets expensive fast.

One other thing, is if its only a few inches, you could lower point 2 and raise point 1, and then use a precast curb along that side of the patio. Granted these things are not really designed to retain soil, but if its just 2 inches, should be fine.

Anyways, I hope you are sufficiently confused now.
This is impressive! your calculation is very close to what I measured, I am planning to make the slope as ¼ inch per foot actually(would you recommend this rate btw?), the distance between 2 and 1 is 16 feet, drops about 9 inches, so I have 5 inches to make up.

1. I am also thinking lower point 2 (2 inches down) and raise point 1 (3 inches up), but will that have issue when we lay down the gravel at point 1? It looks like we have to fill the gravel almost up to the ground level, then 1 inch sand, 2.3 inches(60mm) paver.

2. If we lay the retaining wall block at point 1, do we have to run a length of them along the line between 1 and wagon? because on this line, there is only about 3 feet from point 1 is having a steep slope, the area close to wagon is much better. Can I just lay 3 feet blocks along this line? then put a short drainage pipe behind the blocks, fill the 4 inches crush run to the rest of area. Now, these blocks' top should be same level with the gravel, correct? then compact all of them, apply 1 inch sand, install the paver as you mentioned above when laying on the blocks. Please correct me I am wrong!
Deal Addict
Jun 26, 2019
2003 posts
1734 upvotes
GTA
JeffHill wrote: This is impressive! your calculation is very close to what I measured, I am planning to make the slope as ¼ inch per foot actually(would you recommend this rate btw?), the distance between 2 and 1 is 16 feet, drops about 9 inches, so I have 5 inches to make up.
A 2% grade (which is 1/4" per foot) is a good grade for drainage and if you're going to DIY. I would say usually most patios are installed at 1%, and true professions can install a patio at 0.5%.
JeffHill wrote: 1. I am also thinking lower point 2 (2 inches down) and raise point 1 (3 inches up), but will that have issue when we lay down the gravel at point 1? It looks like we have to fill the gravel almost up to the ground level, then 1 inch sand, 2.3 inches(60mm) paver.
Your gravel is going to extend beyond the base of your pavers anyways. Even if gravel is up to ground level, should be able to raise the grade along the back (between 1 and wheelbarrow) to make it an even transition between patio and landscaped area. As discussed above, for along the fence, probably just looking at either a block or a curb just to hold everything in place if your gravel will be a few inches above grade.

Do you have a plan for along the fence? Assuming you probably might not get super tight to it, were you going to throw down some peak gravel or something, or is your intent to get right up too it? A curb with some peak gravel on the other side would probably fill some dead space you may have, a allow you some space for some 3:1 grading to even everything out.
JeffHill wrote: 2. If we lay the retaining wall block at point 1, do we have to run a length of them along the line between 1 and wagon? because on this line, there is only about 3 feet from point 1 is having a steep slope, the area close to wagon is much better. Can I just lay 3 feet blocks along this line? then put a short drainage pipe behind the blocks, fill the 4 inches crush run to the rest of area. Now, these blocks' top should be same level with the gravel, correct? then compact all of them, apply 1 inch sand, install the paver as you mentioned above when laying on the blocks. Please correct me I am wrong!
So you have two options for the back if you are going to be high.

1. Raise existing grades to meet where your patio grade will be.
2. Install a R/W till the grades catch up.

Generally speaking, although the option 1 results in steeper grading, Id probably do it in this case. I dont really see the point of a RW unless you can have a nice like 6-8inch step down from the patio. Could get away with 5, but to avoid some potential trip hazards, I probably just go with raising the grade in this small area.

For the retaining wall or blocks, in normal construction you would usually have a wall with coping ontop attached with some kind of adhesive (Landscape PL, Mortar, etc). This ensures a good connection and then in turn stops it from moving which provides a nice edge restraint for your patio pavers. In your case, if we're going to cheat on the one side where you wont see it anyways, I would still make sure you fix your pavers to the blocks or walls underneath to stop them from shifting and hole everything in. So basically, the top of your blocks would be about even with the top of your highest base. The base course could stand a little bit proud to allow for a wee bit of gap the adhesive will take up, and then compact the top of the base and adhesive when you install the block. This way the pavers ontop are connected to the blocks and will provide edge restraint for the rest of your patio and not shift outwards because you cant install brickstop in this area.
[OP]
Newbie
Oct 31, 2016
38 posts
7 upvotes
SubjectivelyObjective wrote: A 2% grade (which is 1/4" per foot) is a good grade for drainage and if you're going to DIY. I would say usually most patios are installed at 1%, and true professions can install a patio at 0.5%.



Your gravel is going to extend beyond the base of your pavers anyways. Even if gravel is up to ground level, should be able to raise the grade along the back (between 1 and wheelbarrow) to make it an even transition between patio and landscaped area. As discussed above, for along the fence, probably just looking at either a block or a curb just to hold everything in place if your gravel will be a few inches above grade.

Do you have a plan for along the fence? Assuming you probably might not get super tight to it, were you going to throw down some peak gravel or something, or is your intent to get right up too it? A curb with some peak gravel on the other side would probably fill some dead space you may have, a allow you some space for some 3:1 grading to even everything out.



So you have two options for the back if you are going to be high.

1. Raise existing grades to meet where your patio grade will be.
2. Install a R/W till the grades catch up.

Generally speaking, although the option 1 results in steeper grading, Id probably do it in this case. I dont really see the point of a RW unless you can have a nice like 6-8inch step down from the patio. Could get away with 5, but to avoid some potential trip hazards, I probably just go with raising the grade in this small area.

For the retaining wall or blocks, in normal construction you would usually have a wall with coping ontop attached with some kind of adhesive (Landscape PL, Mortar, etc). This ensures a good connection and then in turn stops it from moving which provides a nice edge restraint for your patio pavers. In your case, if we're going to cheat on the one side where you wont see it anyways, I would still make sure you fix your pavers to the blocks or walls underneath to stop them from shifting and hole everything in. So basically, the top of your blocks would be about even with the top of your highest base. The base course could stand a little bit proud to allow for a wee bit of gap the adhesive will take up, and then compact the top of the base and adhesive when you install the block. This way the pavers ontop are connected to the blocks and will provide edge restraint for the rest of your patio and not shift outwards because you cant install brickstop in this area.
Million thanks, SubjectivelyObjective.
Based on your suggestion, I decided to raise point 1 a bit. There are many other small issues need to be tackled during the installing, but finally I got it done... the whole month.....man..it is harder than I thought, I found lots of little details are not covered or even mentioned in any youtube videos, you will realize that only until you have done it...

Here it is. I really appreciate your help again.
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