Crawl Space Ventilation

[RJMCGUIRE]

Section 1203.3 Under floor ventilation requires all spaces between the bottom of floor joists and the earth under any building except spaces occupied by basements or cellars shall be provided with ventilation openings through foundation walls or exterior walls....

does this mean that any space beneath a slab and the earth below regardless if it is inaccessible has to be ventilated? Or does it have to be ventilated only if it is accessible?

If all spaces have to be ventilated would that mean that a slab on carton forms would also have to be ventilated due to the deterioration of the carton forms and thus a 12 inch void between the under side of the slab and the earth below?

Thanks

RM

 

[MASSDRIVER]

There is an exception for moisture sealed spaces that I have used.

Brent

 

[Gregg Harris]

Section 1203.3 Under floor ventilation requires all spaces between the bottom of floor joists and the earth under any building except spaces occupied by basements or cellars shall be provided with ventilation openings through foundation walls or exterior walls....does this mean that any space beneath a slab and the earth below regardless if it is inaccessible has to be ventilated? Or does it have to be ventilated only if it is accessible?

If all spaces have to be ventilated would that mean that a slab on carton forms would also have to be ventilated due to the deterioration of the carton forms and thus a 12 inch void between the under side of the slab and the earth below?

Thanks

RM

1203.3 would not apply to your scenario the product is designed to deteriorate and leave a void.

1203.3 is designed to protect the floor joists from deterioration.

 

[JBI]

The section does specify between floor joists and the earth.

I agree with Gregg Harris, it's to prevent joist deterioration.

 

[RJMCGUIRE]

thanks everyone.

what about Section 406 of the IMC?

406.1 uninhabited spaces, such as crawl spaces and attics, shall be provided with natural ventilation....or mechanical ventilation?

If I don't provide access to the space its not a crawl space....right? and then doesn't have to comply?

just trying to cover everything I can think of

 

[Gregg Harris]

thanks everyone.what about Section 406 of the IMC?

406.1 uninhabited spaces, such as crawl spaces and attics, shall be provided with natural ventilation....or mechanical ventilation?

If I don't provide access to the space its not a crawl space....right? and then doesn't have to comply?

just trying to cover everything I can think of

Access is not a prerequisite for determining either, you could have the ventilation requirement and not an access requirement.

 

[RJMCGUIRE]

Thanks everyone. your comments helped me gain a better understanding.

with that, I called my code official and we decided that due to section 1209.1 access is required to unoccupied spaces. therefore, due to IMC section 406.6, ventilation is required.

It wasn't as simple as I was hoping. i.e. if it isn't accessible it isn't a crawl space and therefore not required to be ventilated.

at least I was correct in telling the builder he had to ventilate the space :smile:

 

[Paul Sweet]

If I remember my days in Texas a few decades ago, the severe shrink-swell nature of some soils required deep belled piers and carton forms under grade beams to allow the soil to expand without tearing the foundation apart. I don't think this should be considered a crawl space, because it might be filled with soil during unusually wet times.

 

[RJMCGUIRE]

thanks Paul.

you're right on the money. we have a pvr of 6" at this site and therefore added the carton forms and created a crawl space beneath a kitchen so that the extensive plumbing wasn't in soil. then we needed to add crawl space access and ventilation.

due to interior grade beams and like you said soil movement the void created by the carton forms isn't a crawl space. we're only concerned with the actual crawl space at kitchen plumbing that we deepened to about 2.5 to 3 feet.