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-   -   Paver Patio grade issue (http://www.diychatroom.com/f16/paver-patio-grade-issue-180885/)

topher0524 05-30-2013 10:17 AM

Paver Patio grade issue
 
Hi guys I'm getting ready to build a 18x24' patio using 2 3/8" pavers (combination of 6x6 and 6x9). After staking out the area and determining where I'd like everything I've noticed that at one corner my backyard starts to grade pretty sharply. It ends up that in one corner I'll be 7-8" lower.
Does anyone have any advice on how to handle this?
Any suggestions would be greatly appreciated.
Thank you

AGWhitehouse 05-30-2013 01:00 PM

Fill it in or excavate the balance of the patio to create an uniform even slope. Filling in will require blending at that corner, while excavating will require blending at all sides. I'd recommend a max. slope of 2% (1" down for 50" across). This is the max slope for wheelchairs (if applicable) and I did that slope on my patio and any steeper and you will notice it while seated in a chair and walking around.

Do note that 2% slopes in two directions makes for a steeper slope when walking diagonally. So either do a 1% slope in 2 directions or a single 2% slope in one direction and level perpendicular to that direction.

topher0524 05-30-2013 03:46 PM

AGWhitehouse thanks for the reply.
If I decide to fill it in would you recommend any specific filler? would it just be regular dirt or should I use the concrete paver base? Also is there any issue with that area settling and resulting in the patio getting ruined?
I also sketched up the actual dimensions, if you take a look at the gradient area you will see where the lawn starts to pitch. the darkest area represents the 7" below grade.

http://www.doityourself.com/forum/at...atio_pitch.jpg
Thanks Again

brockmiera 05-30-2013 06:07 PM

You could build a little retaining wall and backfill it to level.

AGWhitehouse 05-31-2013 01:27 PM

fill with 3/4" process and top with stone dust for leveling. You'll need to tamp in lifts to minimize settling. I wouldn't place more than 4" depth without a thorough tamping effort. You can do a retaining wall as noted above or get topsoil and fill against patio edge and swail out from there.

Is the 7" difference when the striking a level line from the far corner of the patio? Because a 2% slope over 18ft is +/- 4-1/4" which only leaves you with 3" of soils to deal with...

topher0524 06-03-2013 09:42 AM

yes the 7" difference is when striking a line. Is the 2% slope using the 1/4 per foot theory?
so every 4 feet you would be about an inch lower? to me it seems like that would be pretty noticeable. Any thoughts?

ddawg16 06-03-2013 09:51 AM

A 1/4" per foot is = 2%.

So, in your case that works out to about 4". Over 18', that is not much....truth is, you could most likely get by with half that...or less. Because your using pavers, most of the water will drain between the stones.

Your soil type will determine what you do on the low side. If it's the hard stuff like we have, you could build it just packing it in...after the 1st summer it's like concrete.

I'm thinking your going to need to build a retaining wall to hold the dirt in. Without it, soil will push down and your pavers will start to fall down the hill.

In your drawing you show a circle...build something there an integrate a retaining wall into it. Basically you just want a 4-6" wall to keep the dirt/rock/sand from shifting down the hill.

jomama45 06-03-2013 09:58 AM

You'd have to have a trained eye to notice, or even consider, 2% as being steep. The only way you'll see it is if you have you're head on the ground and can "eye" the elevation up with something level, like the bottom of the siding, etc.... We install 99% of our concrete flatwork with 2% grade or better, it's not an issue, and would be the easiest approach to avoid a retaining wall. And, 2% grade will help sheet the water off of the pavers, rather than allow it to soak through, giving the patio a better chance at a long life......

topher0524 06-03-2013 10:50 AM

Thanks for the responses guys.
ddawg the circle you see in the drawing is actual a circle patio kit from ephenry. if I go with the 4" slope as suggested I'll be right around 3" lower than the desired height. I could mimic the circle section with a rounded retaining wall, maybe two courses high no. bury one block and then add a second course to make up the 3" difference.
I've been filling and compacting and I'm almost at the final grade, just wanted to make sure I'm putting the correct slope in.

AGWhitehouse 06-03-2013 12:27 PM

Just to clarify, technically (I know, I know), 1:50 is 2%, a little shallower than 1/4"/ft. That level of attention only really matters when you're dealing with code for Wheelchair Accessibility as 2% is the maximum slope allowed.

I did a 2% single slope on my patio and it's fine. Don't go more than that or you'll definately begin to notice when your back is facing downhill in a chair. While pavers do allow water to seep through, it's not an instantaneous process. "Flat" patios are never truly flat and have just enough variation to allow for puddles if the substrate doesn't have a high enough perk rate. And with puddling comes the wonderful "mud rings" as I call them where the rain rinses your patio dust and particulate from the air and leaves it behind once the puddle evaporates. It's usually dust/dirt so fine it can't be swept away. So by adding a slight slope you'll eliminate the potential for puddling allow the rains to assist in providing a basic rinsing of that dusty dirt.

topher0524 06-03-2013 02:04 PM

thanks again everyone. one more question, and this may be ridiculous but I may need to go pick up another line level.
When setting the string across the 18ft section I start by making it level. then going to the other end I measure down 4" inches and tie off. However when looking at the level again only 1/4 of the bubble is inside the "level" section. Shouldn't it be the other way around? 1/4 should be outside the "level" indicator
Hopefully this isn't a ridiculous question. maybe I need to go measure again, that, or get some sleep.
Thanks.

brockmiera 06-03-2013 04:13 PM

Quote:

Originally Posted by topher0524 (Post 1194300)
thanks again everyone. one more question, and this may be ridiculous but I may need to go pick up another line level.
When setting the string across the 18ft section I start by making it level. then going to the other end I measure down 4" inches and tie off. However when looking at the level again only 1/4 of the bubble is inside the "level" section. Shouldn't it be the other way around? 1/4 should be outside the "level" indicator
Hopefully this isn't a ridiculous question. maybe I need to go measure again, that, or get some sleep.
Thanks.

Measure close to your stake too where your line is the tightest. The further that level gets away from the fulcrum the more your line will sag. I've learned that lesson the hard way! Snap a few pics and we can help you thru it. I had almost the same situation as you and I built mine level with a 16" tall retaining wall. I live in Colorado though. Not enough moisture here to need much slope.

brockmiera 06-03-2013 04:14 PM

Quote:

Originally Posted by topher0524 (Post 1194300)
thanks again everyone. one more question, and this may be ridiculous but I may need to go pick up another line level.
When setting the string across the 18ft section I start by making it level. then going to the other end I measure down 4" inches and tie off. However when looking at the level again only 1/4 of the bubble is inside the "level" section. Shouldn't it be the other way around? 1/4 should be outside the "level" indicator
Hopefully this isn't a ridiculous question. maybe I need to go measure again, that, or get some sleep.
Thanks.

I also bought a handy line level that actually has the grade marks on it. It makes getting the proper grade pretty damn easy.

topher0524 06-03-2013 08:48 PM

As it turns out it looks like it was the line level. I picked up a new one and it looks like its right on the money.
What are you thoughts on "feeling the slope" at 4"? I'm going to have furniture on it and a canopy. I don't want to feel like you are on an angle when seated.
Would it be ok to just do like 1/8" per foot?

brockmiera 06-04-2013 03:20 PM

Again. I'm not sure where you are. So cal, Arizona, Texas, Colorado sure 1/8" on 12 should be fine. Portland, Seattle maybe not so much.


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