# Height 1st floor to grade



## rktect 1 (May 15, 2017)

Recently we have been having a lot of people come in to remove a wood deck and install either brick paver patios or concrete patios.  These are generally from a home with a crawl or basement.  Top of foundation is supposed to be 6 inches higher than grade and with 2x10 floor joists this usually puts the 1st floor to grade at 18.75 inches.  Per 311.4.3 of the 2006 IRC, I have been asking for the landing outside of the exterior door.  Of course the contractor just wants to install the patio 7 3/4" lower than the 1st floor which means pouring the patio right up against the siding because a home with 2x10 floor joists with a 7 3/4" drop will produce this situation.  I keep telling them they have to drop their patio to 6 inches below grade but create a landing and steps with a foundation or using 8" diameter concrete piers.

Does anybody else run into this these days?  Its usually a big battle once in a while when I don't let them build up grade against the foundation wall and sometimes siding.  The landing always gets flashed but the patio still needs to be 6 inches below top of foundation.


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## Paul Sweet (May 15, 2017)

It can be done if there is metal flashing to separate the floor framing from the concrete.  This isn't too difficult on new construction, but retrofitting it can be a real challenge.


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## Keystone (May 15, 2017)

We do not run into this due to Pennsylvania not requiring permits for many items, however I view the scenario and come to the same conclusion as you. I would also be concerned, if full basement the addition of backfill against the existing foundation walls.


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## CityKin (May 15, 2017)

We use the 2009 IRC and IRC 311.3.2 (exception) allows two risers on the exterior door and our risers are allowed to be 8.25" thus the patio can be 16.5" below threshold before a landing is required.

I'm not sure where you are getting the 6" exposed foundation requirement.

(whoops, I see it now 2009 IRC 404.1.6)


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## Francis Vineyard (May 15, 2017)

Note the exceptions of wood that is preservative-treated in section 319 (2006) where the sills, sleepers and wood structural members are separated from the concrete with impervious moisture barrier i.e. prescribed 6 mil Polyethylene film. This aligns with the construction of wood foundations moisture barrier provision as applicable in R406.3 and Figures R403.1.(2) & R403.1(3) where the exterior preservative treated plywood without the film extends above the grade protecting the regular wood sill.

Beginning in the 2009 edition the 6 inch clearance is reduced to 2 inches from exposure to concrete (Ref. R319.1 item 5).


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## TJacobs (May 20, 2017)

rktect 1 said:


> Recently we have been having a lot of people come in to remove a wood deck and install either brick paver patios or concrete patios.  These are generally from a home with a crawl or basement.  Top of foundation is supposed to be 6 inches higher than grade and with 2x10 floor joists this usually puts the 1st floor to grade at 18.75 inches.  Per 311.4.3 of the 2006 IRC, I have been asking for the landing outside of the exterior door.  Of course the contractor just wants to install the patio 7 3/4" lower than the 1st floor which means pouring the patio right up against the siding because a home with 2x10 floor joists with a 7 3/4" drop will produce this situation.  I keep telling them they have to drop their patio to 6 inches below grade but create a landing and steps with a foundation or using 8" diameter concrete piers.
> 
> Does anybody else run into this these days?  Its usually a big battle once in a while when I don't let them build up grade against the foundation wall and sometimes siding.  The landing always gets flashed but the patio still needs to be 6 inches below top of foundation.



We also require the landing to be the first thing you step down on, then steps to grade/patio.  We have an amendment requiring this.


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## kilitact (May 21, 2017)

A patio can be both landing and patio. Also agree with below.



Francis Vineyard said:


> Note the exceptions of wood that is preservative-treated in section 319 (2006) where the sills, sleepers and wood structural members are separated from the concrete with impervious moisture barrier i.e. prescribed 6 mil Polyethylene film. This aligns with the construction of wood foundations moisture barrier provision as applicable in R406.3 and Figures R403.1.(2) & R403.1(3) where the exterior preservative treated plywood without the film extends above the grade protecting the regular wood sill.
> 
> Beginning in the 2009 edition the 6 inch clearance is reduced to 2 inches from exposure to concrete (Ref. R319.1 item 5).


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## steveray (May 23, 2017)

I'm with Citykin....no risers door does not swing over, no landing.....Don't "attach" it to the house and you don't need to frost protect...


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