Porch slab same level as house slab???

It was always my understanding that the finished level of the porch should be at least 1 1/2 inches lower than the slab itself to prevent moisture intrusion. I’m looking for something to back that up. Codes? Standards? Tried the IRC but haven’t found anything there yet. Look at the pics and tell me what you think please.
Thanks in Advance!

The porch slab is the least of your worries… it looks like they are doing brick and yet I do not see any flashing that should be tucked under the vapor barrier that will allow moisture to make its way out of weep holes.

The problem with slabs is that builders rarely get them off the ground and as you are finding the porch issue…yes this porch is under roof but still.


Already busted them on the lack of moistop at the brick ledge…

George, try your good glasses ;~))

R311.4.3 Landings at doors. There shall be a floor or landing
on each side of each exterior door. The floor or landing
at the exterior door shall not be more than 1.5 inches (38
mm) lower than the top of the threshold. The landing shall
be permitted to have a slope not to exceed 0.25 unit vertical
in 12 units horizontal (2-percent).

  1. Where a stairway of two or fewer risers is located
    on the exterior side of a door, other than the
    required exit door, a landing is not required for the
    exterior side of the door provided the door, other
    than an exterior storm or screen door does not
    swing over the stairway.
  2. The exterior landing at an exterior doorway shall
    not be more than 7 3/ 4 inches (196 mm) below the
    top of the threshold, provided the door, other than
    an exterior storm or screen door does not swing
    over the landing.
  3. The height of floors at exterior doors other than the
    exit door required by Section R311.4.1 shall not be
    more than 7 3/4 inches (186 mm) lower than the top
    of the threshold.
    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.

Yes sir I guess it’s time to turn the readers in for the real thing!!
Thanks a ton!!

For handicapped accessibility. Being level with the house slab is permitted.

Joe these houses are in fact supposed to have a no step entry at the door. Most of our contractors just slope the area right in front of the door but these guys are sloping the whole porch. There will be brick on the porch but even then do any of you have concerns about moisture and the sole plate?
Thanks All!

All porches should have a noticeable slope to ensure positive drainage away from the house. I often verify a slope with a marble and if there is no slope, I write it up as a defect (will lead to standing water and possibly ice). I don’t see any issues with the porch from here. The sole plate should be treated wood or isolated from all concrete in all cases.

Thanks again!

I wouldn’t classify the porch as a landing but rather a floor…and I dont see a minimum…only maximum. I don’t think that code applies in this case.

My construction business actually does handicap work so these actually work out great…even so in cases where there is a covering, I don’t see a problem.

I thought the same:

why would it not apply?

pix are of exterior entry door with floor at both interior and exterior

it complies correct?

R311.4.3 Landings at doors. There shall be a floor or landing
on each side of each exterior door.

just for clarification: if anyone interpreted what i posted as it should have a step up that’s not what i said or code implies

Porch slab like that should be 1-1/2" lower than the threshhold.

If not, it needs to be flashed properly to prevent water infiltration to the home slab under the wall framing.

The only picture I have that is similar is this one where the slab was poured 2-1/2" lower to install brick pavers that would bring it flush to the slab of the house. Same difference basically.
This is what I did.

This was at an existing Housing for Habitat for Humanity that I worked on.

In the case of the picture above, a saw kerf would have to be made on the slab and a bent piece of copper flashing bent and sealed in it up the wall to provide a water tight flashed juncture between the too.
And yes, the brick shelf would have to have flashing brought up behind the WRB.
Hope this helps. :slight_smile:

Thanks for the clarification, Barry. :slight_smile:

Im speaking from a code standpoint…as a builder in North Carolina, if an inspector is going to call out code…and that’s what is at issue since it new construction…you would have to cite the code and provide documentation of the code. As the code reads it here it gives a max height…nothing else.

Look at it carefully…The floor or landing at the exterior door shall not be** more** than 1.5 inches… well its not more than 1.5…is actually less.

The 7.5 inches is dealing with a landing…not a floor.
The exterior** landing** at an exterior doorway shall not be more than 7 3/ 4 inches

The porch is actually a floor… a concrete floor that extends the length of the porch. If there was a minimum height than it would be problematic for ADA requirements.


I’m starting to agree that since these houses are brick it’s probably ok. BUT when we do hardi plank instead I see no way they could get the manufacturers speced clearance with the porch like this…the sole plate would be exposed then.
Thanks again all!

Cementitious siding is suppose to be 1.5 - 2 inches of the ground and above concrete so some sort of flashing would be required…however most builder for aesthetic reasons will put the cementitious siding about a 1/4" inches of the ground in those cases. Yes, the porch floor should have / could have been dropped however that fact that its not and being brick with flashing… I personally would not have an issue with it.

In the code, “floor” and “landing” are used synonymously.

“R311.3 Floors and landings at exterior doors. There shall be
a landing or floor on each side of each exterior door.”

“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.”

A landing always constitutes having steps and will have additional codes that deal with door swing, number of steps be guardrails are necessary etc…a floor necessarily does not as is the case with a monolith slab.

Thank u so much!! I’ve been looking for this info!