Thread: Grade on cement or hardscape surfaces

Hello all,

I have been looking for any code on grade for cement walkways or patios. I know exterior soils should be 6" in 10' or 5 %, yadda yadda.

But I can not find any hard numbers for cement, asphalt, pavers surfaces etc...

I know most call for 1/8 or 1/4 per foot but is there a standard?

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Originally Posted by Don Hester

Hello all,

I have been looking for any code on grade for cement walkways or patios. I know exterior soils should be 6" in 10' or 5 %, yadda yadda.

But I can not find any hard numbers for cement, asphalt, pavers surfaces etc...

I know most call for 1/8 or 1/4 per foot but is there a standard?

Don, FYI, cement is one ingredient of concrete. Concrete is the finished product.

My take on that question is that the correct slope of the concrete walkways is 6"/10', as it is "on grade".

CCS 411.3.1
All hard paved (concrete/ masonry) walks, driveways and patios contiguous to the building's perimeter foundation should have a minimum slope of 2 % directed away from the building's perimeter foundation support system.

John, You are correct about cement I was being lazy with terms, my bad. I should of used concrete.


Jerry, Thank you that was what I was looking for. I know many contractors use the 1/8 or 1/4 per foot rule but I wanted to know what the definitive answer was.

Jerry, Must ask stupid question what does CCS stand for?

There is no such thing as a stupid question Don; it's just stupid not to ask for an explanation including a codified reference if there is one.

CCS = Code of Common Sense.

A question asked just for the sake of getting attention is a stupid question.

Though a question to learn from is never a stupid question.

Originally Posted by Don Hester

Hello all,

I have been looking for any code on grade for cement walkways or patios. I know exterior soils should be 6" in 10' or 5 %, yadda yadda.

But I can not find any hard numbers for cement, asphalt, pavers surfaces etc...

I know most call for 1/8 or 1/4 per foot but is there a standard?

Although I agree mostly with Jerry McCarthy regarding the generic 2% "minimum" where adjacent to building walls (that comes from 2009 IRC 401.3 Drainage and its exception, by the way) should the patio, walkway, etc. portion be a LANDING (ramp or stairway, egress) it is LIMITED to a 2 percent slope MAXIMUM, and if part of a stairway - continuity overall may further limit the slope. The patio or walkway must also not exceed the parameters for a Ramp 1 in 8 (12 percent) max exeception, and should it exceed a slope prescribed (1 in 12 or 8.33 percent) it will require a handrail. Depending upon elevations of such surfaces to adjacent grade may further require guards and/or handrails. Care must also be taken where adjacent to building openings regarding "landings" and egress regarding EERO exit passageways and basement stair hatches; all while maintaining the minimum prescribed foundation elevations above finished grade surfaces.

Presuming all are above ground finished surfaces, and not in a flood hazard zone...and that you meant concrete and other impervious surfaces....and there isn't a special provision due to your soil conditions, geo tech. surveys, (401.4, 309.3, etc.)...and you're keeping in mind a slope from carport or garage floor, the apron and not compromised or compromising drainage from same...

Keep reading on through the "yada yada" at the drainage requirements you started to reference yourself, go back to definitions in chapter 2, and follow up with the means of egress requirements for those landings 2% max), walkways (see floors- 506.2), etc. and determine if you actually have a ramp, or a max. exception ramp, and one which may require handrail(s). You WILL find several Codified references.

Below from 2009 IRC:

GRADE. The finished ground level adjoining the building at all exterior walls.

GRADE FLOOR OPENING. A window or other opening located such that the sill height of the opening is not more than 44 inches (1118 mm) above or below the finished ground level adjacent to the opening.

GRADE PLANE. A reference plane representing the average of the finished ground level adjoining the building at all exterior walls. Where the finished ground level slopes away from the exterior walls, the reference plane shall be established by the lowest points within the area between the building and the lot line or, where the lot line is more than 6 ft (1829 mm) from the building between the structure and a point 6 ft (1829 mm) from the building.

STORY ABOVE GRADE PLANE. Any story having its finished floor surface entirely above grade plane, except that a basement shall be considered as a story above grade plane where the finished surface of the floor above the basement meets any one of the following:

1. Is more than 6 feet (1829 mm) above grade plane.
2. Is more than 6 feet (1829 mm) above the finished ground level for more than 50 percent of the total building perimeter.
3. Is more than 12 feet (3658 mm) above the finished ground level at any point.

• R401.3 Drainage. Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall a minimum of 6 inches (152 mm) within the first 10 feet (3048 mm).
  • Exception: Where lot lines, walls, slopes or other physical barriers prohibit 6 inches (152 mm) of fall within 10 feet (3048 mm), drains or swales shall be constructed to ensure drainage away from the structure. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped a minimum of 2 percent away from the building.
• R311.3 Floors and landings at exterior doors. There shall be a landing or floor on each side of each exterior door. The width of each landing shall not be less than the door served. Every landing shall have a minimum dimension of 36 inches (914 mm) measured in the direction of travel. Exterior landings shall be permitted to have a slope not to exceed 1/4 unit vertical in 12 units horizontal (2-percent).
  
  • R311.3.1 Floor elevations at the required egress doors. Landings or floors at the required egress door shall not be more than 11/2 inches (38 mm) lower than the top of the threshold.
    
    Exception: The exterior landing or floor shall not be more than 73/4 inches (196 mm) below the top of the threshold provided the door does not swing over the landing or floor.
    
    When exterior landings or floors serving the required egress door are not at grade, they shall be provided with access to grade by means of a ramp in accordance with Section R311.8 or a stairway in accordance with Section R311.7.
• R311.7.6 Stairway walking surface. The walking surface of treads and landings of stairways shall be sloped no steeper than one unit vertical in 48 inches horizontal (2-percent slope).
• R311.8.1 Maximum slope. Ramps shall have a maximum slope of 1 unit vertical in 12 units horizontal (8.3 percent slope).
  
  Exception: Where it is technically infeasible to comply because of site constraints, ramps may have a maximum slope of one unit vertical in eight horizontal (12.5 percent slope).
  
  • R311.8.2 Landings required. A minimum 3-foot-by-3-foot (914 mm by 914 mm) landing shall be provided:
    1. At the top and bottom of ramps.
    2. Where doors open onto ramps.
    3. Where ramps change direction.
• R311.8.3 Handrails required. Handrails shall be provided on at least one side of all ramps exceeding a slope of one unit vertical in 12 units horizontal (8.33-percent slope).

HTH.

Thanks, HG, and Jerry.
For people that don't do the math,

6"/10' is 0.5' / 10' or 1 in 20 = 5 in 100 or 5%

1/4" / 12" ( one ft ) is 1 in 48 = 2 in 100 or 2%

Originally Posted by John Kogel

Thanks, HG, and Jerry.
For people that don't do the math,

6"/10' is 0.5' / 10' or 1 in 20 = 5 in 100 or 5%

1/4" / 12" ( one ft ) is 1 in 48 = 2 in 100 or 2%

You worked that out all by yourself? Wow, I think I might move up there. There must be something in the drinking water that brings one to that level

Originally Posted by Ted Menelly

You worked that out all by yourself? Wow, I think I might move up there. There must be something in the drinking water that brings one to that level

Ted,
I know you say that in jest, but it is sad that so many could not.

John,
Kudos to you for the brain power.

• Landings, stair treads = no more than 1/4 unit in 12 (literally just a bit over 2%, 2.083%, maximum)
• Impervious surfaces adjacent to foundations and for 10' f out (other than landings, stair treads, etc. 2 % (1 in 50) minimum
• Non-impervious surfaces adjacent to foundations and for 10' out no less than 1/2 in 10 (or 1 in 20) or 5% where proximity or obstruction prevents full fall of 6" over 10 ft - must install drains or swales.
• Ramps (excluding landings) prescribed = no more than 1 in 12 without a handrail (8.33 %)
• Ramps (excluding landings) with required handrail, exception = no more than 1 in 8 (12.5 % maximum).
• Balance of lot must promote not prevent surface drainage away from founations to an approved diversion or collection point that does not create a hazard.

That's the short version, went long at first because the OP appeared to desire the code citations and language.

HTH.

Originally Posted by Ted Menelly

You worked that out all by yourself? Wow, I think I might move up there. There must be something in the drinking water that brings one to that level

No fear, Ted. You'll be drinking our water soon enough, if we could just figure out who should get paid for it at our end.

And that post was for people who don't do math. Glad you liked it.

Don,all your tolerances for slab construction tolerances, flatness and levelness start with ACI (American Concrete Institute) 302.1R

As an old Road builder, Grade Checker and Cement Finisher - everything was done at 2% the majority of the time - it was the "rule of thumb." Whose thumb I don't know.

Originally Posted by Jim Hintz

As an old Road builder, Grade Checker and Cement Finisher - everything was done at 2% the majority of the time - it was the "rule of thumb." Whose thumb I don't know.

Dido. Lots of concrete work in the background as well. Come to think of it too much of every type of work in my background. 2% was pretty much the norm until you hit all those sloped lots tht drives had to make it up. Around the home was about 2% because anymore , for one, would look foolish with too much slope such as patios and walkways.

Originally Posted by Ted Menelly

Dido. Lots of concrete work in the background as well. Come to think of it too much of every type of work in my background. 2% was pretty much the norm until you hit all those sloped lots tht drives had to make it up. Around the home was about 2% because anymore , for one, would look foolish with too much slope such as patios and walkways.

I learned all this slope,fall, percentage stuff as a kid, my Dad had his own Heavy Construction Company and taught me well. If you have spent time on a big Cat, you know when your behind is level or if it's off just a tad cause that's how you used to run big dozers - you couldn't see over the pile in front of the huge blade and you cut grade / slope by the seat of your pants. Nowdays they use GPS & Lasers, nobody knows how to do it the Old School Way anymore.