View Full Version : raised patio
05-18-2003, 09:01 PM
When building a raised patio using segmental retaining blocks, how do you address where the blocks meet the pavers. The blocks are level, while the pavers have a slope to them, and with a patio that is 25 feet wide, with a 2% slope, you may drop 6 inches. Any suggestions.
I know what you are asking but a bit more info may help... is the patio completely surrounded by the wall? or is it boxed in by the house? If it is completely out in the open you my be able to just crown your pavers in the middle and have a slight runoff ..you can get away with 1% for a paved surface. If you have a sketch it would help ... you may also be able to build up the sides 2 high stepping down to one ... lots of solutions If I knew exactly the challenge.
05-19-2003, 12:06 PM
More detailed info please. I would post some pics but I haven't figured how to get it from the scanner to the post yet. Sorry:rolleyes:
05-19-2003, 09:49 PM
The patio is surrounded by a retaining wall on 3 sides. The patio will slope away from the house. The patio will be 25 feet wide, so even at 1%, you will still have a difference in elevation on 3 inches. I was think about stepping the wall 1 block and hiding the step with a planting bed.
How wide is it accross the house wall? You could crown it (in cross section) and taper it to a sheet wash as you get farther out.
Are you planning to put the patio tight to the wall? You might consider a planting bed to take up the grade change between the patio and wall then there will be no problem. You also make an aesthetically nicer patio space. It is also safer as the plants give a visual cue that the patio ends, so people are less likely to take a step backward and fall off the edge (who are they going to sue?).
05-20-2003, 11:38 AM
Make the width of the patio level and the sides that are coming away from the house should be pitched away from it.. Meaning the block thats at the houlse should be say 3"s higher than the one on the end corner of that side, so then when the pavers go in its' all nice and even and properly pitched... Youll need to use chaulk lines along the house and plenty of string lines...
06-01-2003, 12:08 AM
If you are saying that the wall is already constructed then these responses are good. If the wall is not built then all you need to do is slope the blocks and pavers at the same slope. 1-2% is all you will need.
I am planning a similar job also, so I'm glad to see this same question I have posted. In my case there is an existing timber wall we are removing, and some patio block is rough laid on the existing soil & being removed. Wall & patio are 3 feet high.
Zedosix, how do you slope the wall, when they are installed level??
What I'm thinking of doing is running the slope down from the house & using bullnose pavers for the edge the slope comes to. So the edges meeting the house & the front of the wall will be level, like the wall. I'll use a different color for the bullnose (and continue that color for the soldier course) to help contrast the drop off. I was also thinking of installing some paver lights near that edge to help indentify that area at night. On the one side I am thinking I will just use the wall caps & step up half way to have the wall slightly above the patio. On the other side we're putting in steps, so I think I'll do the same thing with those walls, just use a second cap to step up the wall on the far side where it continues to the house past the steps. Now if the client doesn't want to do that, they were considering the wall be higher than the patio slightly. In that case, I'm thinking of using the same slope & just installing a couple of drains with grates at the sloped edge to get the water out. Other option is to cut some holes into the wall where needed? Or, does anyone have other ideas??
Another question I have is should all of the area behind the wall & under the patio be removed & then base installed? Or can the normal amount of base be installed onto the existing soil, except where I need to excavate for the wall?
06-05-2003, 11:18 AM
In most if not all cases the retaining wall will have a slope to it. Where the ret. wall meets the house on both ends...they should be at the same height ..ie level. Now leading out from the house it would be wise to drop the wall about 1/8" - 1/4" per foot. This is standard grading practise. If your patio is 20 feet long you will have between a 2-1/2" - 5" drop from house to end of patio.
Construct your wall and cap, back fill with appropriate stone ( here we have lots of frost so some clear stone is required directly behind the wall.)
As for the other question, Ideally you would excavate the entire area to the same depth. Here we have alot of clay so we would excavate and slope the base. If it is a sand or stone base then I would just dig a trench for the wall and remove the top layer of grass and loose dirt before installing my base for the remainder of the patio.
I think you will have a nicer finish to the patio if interlock and wall are at the same height.
Hope its not too confusing. Good luck
"Now leading out from the house it would be wise to drop the wall about 1/8" - 1/4" per foot. This is standard grading practise."
Yep, I'm confused.
All of the brands of concrete segmental retaining walls that I have used or seen used are designed to be installed level. I've never seen one installed not level (except DIY's, and those walls are usually having more than just problems with being level ;) ) None of the installation instructions show a method of installing them at a slope, so I'm assuming the sides that are at an angle would just need a miter cut to make them match the front section of the wall that will be level. But the corners of the wall need to have the blocks interlocked with each side so that wouldn't work either. There would be a bad eneven gap where the side wall meets the front wall because one course would have a miter cut 12" from the corner, then the next course the miter cut would be 6" from the corner etc. etc. Nope that is not possible. The other problem I see with that is that they aren't designed for that, so the side walls might put unneeded pressure onto that front face of the wall (kind of like the hydrostatic pressure that gets put onto them). Also, would that interfere with the integrity of the retaining strength of the geotextile fabric, by having one end a few inches higher than where the rest is installed (probably not, but maybe?)? I think I will stick to following the installation instructions & keep the wall level. Maybe there are other brands that are designed for that type of installation, but the Versa-Lok we're using for this one does not specify a sloped installation, especially considering the above mentioned problems at the corners .
06-05-2003, 01:10 PM
Let me ask you this. If you were building a large front step, would you also set the blocks level or would you slope them slightly. I really don't understand the problem. If you have one block set in the ground and a restraint edging on the side of the wall there should be no problem with this. I think at 1/8" or a 1% slope there should be no problem whatsoever. Any other way would seem like a home job. Up here we use support pins in behind the blocks, glue for the capping stone etc. We don't have any problems with it.
06-05-2003, 01:17 PM
I just re-read your response and I am totally confused as to what the problem is. Even with a slightly sloped wall you WILL NOT have any problems with the corners. As to where the block meets up with the house foundation that is no problem. You will not even notice the slight gap. I mean on a block of 6" in height there would be maybe a 1/16" gap at the top of the block. Most foundation walls are not perfectly straight anyway. So there may be some cutting of the block here but thats it. Do you do this often or is this new to you. Just curious.
I've done a bunch of patios\walks, and a bunch of walls, but never a raised patio on top of the wall.
OK now I understand what you are getting at, and I think the confusion is because you are answering a different question basically. I think you missed the part about how these are being done. They are not simply one retaining wall face at the end of the patio. The retaining walls will be installed in a rectangle shape (3 sides) and level, and I posted that mine would be 3 feet high. So now maybe you understand why I am saying that this wall can't be installed at a slope? Now based on my understanding of the solution you have presented, if I was installing just one wall at the front of the patio edge, I still think the wall should be installed level as per the installation instructions. You wrote " I think at 1/8" or a 1% slope there should be no problem whatsoever." This wall will be retaining over 40 cubic yards of soil\fill, plus the patio. Installing this type of wall with a forward batter will undermine the structural integrity of the system, and expose it to potential damage due to bearing capacity failure, or due to overstress\breakage of the reenforcing geotextile fabric. I'm not an engineer, but that's my guess of what the engineer would say about doing that type of wall in that manner. On a smaller wall without so much internal force against then I would agree with your solution. In my case, if I went with your solution, when we looked at the side legs of the rectangle, they would be 3" higher than the front main leg of the wall, and that would certainly look like a "home job". That's why one of my posted potential solutions was to simply step down the wall by one course (or maybe a cap course), to keep the wall level & not have the edges of the patio exposed. Hopefully that explains the question we were asking. Thanks for helping as well.
Below is what I had started typing before I guessed that maybe you didn't see this was a rectangle shaped wall we were asking about, and subsequently figured out what you meant:
The orginal thread question, and my question is; how do we make a sloped patio look good connecting to a level retaining wall. You posted to make the retaining wall sloped like the patio, but you haven't given the details as to how that can be done. I posted the many reasons that I have found that the retaining has to be installed level. You posted that it is OK to install the retaining wall at a 1-2% slope. I tried to figure out how that can be done, and can't figure it out. So I am confused. We are not concerned about the wall meeting the foundation, because the walls we plan to install will be level, as per the installation instructions. However, the patio will need a pitch, and where the sloped patio meets the level wall is what we are asking about. And since you questioned me, based upon your suggestion to incorrectly install the wall, I have to ask out of curiousity as well, do you have any experience with this type of install? ;) :D
06-05-2003, 07:30 PM
I do understand the question. I realize you will be constructing a 3 sided retaining wall. My answer remains the same. Slope the wall and pavers the same.
06-06-2003, 01:49 AM
Retaining wall builders are to be laid perfectly level.
Steps have a slight slope
Patio have a slight incline.
For the patio have it butt right up to the cap stones and make it perfectly flush with the caps.
This will provide an edging for the pavers, and make for a decorative looks, AND will solve most of your drainage problem.
06-06-2003, 05:26 AM
If I were to build just one retaining wall in front of a raised patio, yes this wall would be perfectly level. When you are building a 25' long patio or even a 10 foot long patio it would not collapse with such a small slope. I don't know what kind of blocks you guys are using down there but maybe you should stick with what you do best. Cutting grass:D
Man you guys are looking at way too much slope. ICPI standards are like 3/8" to 1/2" over 10'. Crown 3/4' to 1" a ways from the house and use poly sand to limit absorption. LGF hit it on the head as far as the wall, its got to be level.
06-06-2003, 11:43 AM
All retaining walls need to be level.
Pavers need to have 1 to 2% slope away from foundation.
Retaining wall must not have stack bond pattern.
Are your steps external or internal? If internal they need to be level as they are part of the wall system. If external they can have pitch.
BTW: I am an instructor for the ICPI. I teach the basic certification class.
06-06-2003, 10:13 PM
I have installed this type of stone hundreds of times, including the job you see here which is currently being used in a major manufacturers brochure. So who cares right. No big deal. If I were to take on this job of building a 3 foot high raised patio, I would first remove the front wall and construct as a complete unit. Definitely would not add to an existing wall. I think this is where the problem arises. I will agree though that the more your wall is sloped the possibility of movement is greater. This block in particular which is very popular up here has a 3/4" set-back per 6" rise. A structurally sound block, not like the round backs of yesteryear. What types are you using?
I find that a wall and brick intergrated patio should be of one equal slope. Normally a patio without a retaining wall we will set at 1/8" per foot slope, 1/4" max. A raised patio with interlock we set the slope at 1/8" per foot max. Over the years I have not seen any so called collapses of my projects. A crowned patio in my mind is unsightly. I took the ICPI course 5 yrs ago in Toronto and was happy to see that they are trying to set standards.
06-06-2003, 10:14 PM
Hope this works ...if not I give up.
Glad to see Rex weigh in on this. A slight crown is very unnoticable (sp) in most cases. I can't slope a retaining wall, to me its like putting ketsup on ice cream. You can do it, bit it just ain't right.;)
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