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tractrpowr45
02-13-2006, 09:34 PM
Hi, I am starting a landscaping business in the spring, and I was wondering how you set the right pitch for a paver patio. I know that you are supposed to have a 2% pitch, but I was wondering how you accomplish that? Do you just screed the sand slightly out of level before laying the pavers? I know a slight pitch is needed to shed rain away from the patio, but I'm just not sure how to do it. Any help is very much appreciated. Thanks headphones

LandscapePro
02-13-2006, 10:04 PM
tractr,

Set your pitch with your base. Then screed an inch or so of sand evenly on which to set the pavers.

1 inch fence rail works real nice. It doesn't take a whole lot of pitch to shed water. I usually go with an inch to an inch and a half for every 8 feet of run.

Hope this helps...

Mike
La. Landscape Contractor #2576

UNISCAPER
02-13-2006, 10:09 PM
I'll assume you know what 1,2,3% gradiations are and go to the methods.

We usually set the grade in the gravel and soil excavation application. Since you are just starting out, you probably don't have a laser or site level, so, you will have to use string lines. You drive stakes every 8' in square box configurations and draw strings level across the gravel. Measure from the string to the top of the gravel, the end farthest from the house will have more distance between the string and the gravel.

After you set the gravel base and compact it to the grade you want, just drop your 1" pipes on top of the gravel and screed an inch of sand over the base. Then lay the pavers.

If you are yuppifying your operation with a lazer or site level, you won't need the strings, you can just shoot a 8' diameter grid pattern across the patio and your good to go.

In weird applications we have had to keep both ends at the same grade and drop the center of the patio and set drains within. We tend to go 1% on those applications.

PurpHaze
02-14-2006, 08:46 AM
In weird applications we have had to keep both ends at the same grade and drop the center of the patio and set drains within. We tend to go 1% on those applications.

Bill... Is this so you won't end up with a noticeable dip area in the patio, whether to the eye or the feet and balance of someone walking in the area?

UNISCAPER
02-14-2006, 09:37 AM
Haze:

In Ca., it is illegal to dump water from your yard on someone elses yard, where in other states, it's acceptable to place it on the lot lines from both yards. So, when you have a 15' deep back yard that the client wants paved, the only way to keep the water inside the lot lines is go with a 1% pitch from both ends toward the middle and bring some 4" square brass topped drains to the elevation the brick sits at. Looks has nothing do do with it, it's something they need to deal with because of the codes. In all reality, it is only an inch low on center, so, it's noit as bad as it sounds.

cgland
02-14-2006, 09:33 PM
Bill - Where do you take the water in this application? Into the rain leader system?

Chris

UNISCAPER
02-14-2006, 11:53 PM
Chris:

99% of all yards built within the last 10 years have an underground system of drains. Typically, they install a 4" SDR-35 rigid pipe and place atrium topped drain grates in low spots the yard had been graded to. So, when we come in, we gauge where the pipe is, and many times we end up taking an ultrasound to find how deep the pipe is, set the lazer to the depth we need without destroying the pipe, and add as much or as little as we need. Most of the time, gutter downspouts are never added to the system, let alone if the builder included gutters on the house. So, the drains we place in a patio would typically connect to the main builder installed system.

Then there are those which don't have drains. That makes for a nice $6-7,000 add on to the job, and many times I would just as soon do the drains myself. Open the trenches, set the pipe, back fill and wack the trench.

neversatisfiedj
02-15-2006, 07:39 AM
Have anyone ever installed a drain in the middle of the walk and drained into a gravel pit ? If you could not outlet water to lower elevation ?

PurpHaze
02-15-2006, 08:24 AM
Haze:

In Ca., it is illegal to dump water from your yard on someone elses yard, where in other states, it's acceptable to place it on the lot lines from both yards. So, when you have a 15' deep back yard that the client wants paved, the only way to keep the water inside the lot lines is go with a 1% pitch from both ends toward the middle and bring some 4" square brass topped drains to the elevation the brick sits at. Looks has nothing do do with it, it's something they need to deal with because of the codes. In all reality, it is only an inch low on center, so, it's noit as bad as it sounds.

Thanks Bill.

PurpHaze
02-15-2006, 08:34 AM
Have anyone ever installed a drain in the middle of the walk and drained into a gravel pit ? If you could not outlet water to lower elevation ?

These are called "dry wells" in our area. We had one school built about 12 years ago that used these dry wells as a means of sending large HVAC unit's condensation lines to. They located the dry wells in turf areas only about five feet from drain inlets to the storm drain system. Before the school opened I was doing an irrigation system walk-through and asked someone what would happen when the irrigation water filled the dry wells. Answer: "Architects know what they're doing." This worked fine in the spring when the irrigation program times were minimal but the dry wells started filling up when we changed to hot weather programs. In turn the condensation lines stopped working. Within two years they had to go in and reroute the condensation lines into the storm drains. :dizzy:

An afterthought. They do use dry wells successfully for smaller HVAC units on portable buildings.

jamo1911
02-17-2006, 04:26 AM
Where in NY are you? I remember thoes days, I could show you rather easily how to do it.

UNISCAPER
02-17-2006, 09:34 AM
Before you make adry well, make sure you check the perculation of the soil you are placing it in. If you have soils that won't drain all making a well will do is cause water to sit dormant, creating lots of other problems, particularly if you have a walk over the well. You could end up jacking out the walk you just paid to install.

kris
02-17-2006, 10:47 AM
. I know that you are supposed to have a 2% pitch, but I was wondering how you accomplish that?


I made this sheet up for the guys ... shortened it a bit here


There is one basic formula ...it can be applied to many questions involving grading.

G is the gradient (slope expressed as a decimal)

D is the difference in elevation between two points

L is the horizontal distance between two points

G=D/L or L= D/G or D= GL

G = D divided by L
Use this to figure out the slope between two points when the difference in elevation is know and the horizontal distance between them is known.

L = D divided by G
Use this to figure out the horizontal distance between points when the gradient and difference in elevation is known

D = G times L
use this to figure the difference in elevation between points when the gradient and distance is known


To convert gradient to % slope times by 100

just a quick example of the D=GL formula..

if you have a field 100m long and you require 5% slope for drainage... the elevation at the low end is 5m, what will the elevation be at the other end?

D=GL
D= .05 x 100 = 5
5+5 = 10m

sheshovel
02-17-2006, 03:39 PM
Can you do that for us in feet kris?

kris
02-17-2006, 03:42 PM
Can you do that for us in feet kris?

I can Miss She but read my sig line canada

kris
02-18-2006, 08:11 PM
Can you do that for us in feet kris?


Come on Sheshovel ..dont give up on me ... can you tell me what percentage of slope it would be in the example in this thread of 1" drop over 8' ?

change that 1" into a decimal and then use the G=D/L formula

sheshovel
02-19-2006, 02:53 PM
UUUHHH 16mm?

freddyc
02-19-2006, 03:14 PM
UUUHHH 16mm?


1 meter = 3.28 ft. So in his example, 100m = 328 ft.

kris
02-20-2006, 11:03 AM
I think you misunderstood me ...

someone said 1" drop over 8 feet

first change the one inch by divided 12 inches into it ... 1/12 = approx .08

G=D/L

so in this case D is .08 ...the difference in elevation

L is the 8 feet in distance between the two points

.08 divided by 8 feet = .01

So .01 is G or the slope expressed as a decimal ... times that by 100 to give you the slope in a %

the answer is to the question of what percentage of slope was the poster in this thread (drop of 1" for every 8 feet) telling you to use is 1%