# Pier foundations



## Avins (Oct 20, 2013)

I live in SC, we are using the 2012 IRC. I have been in building most of my life but recently joined the inspection department. In my years of building I only built spec homes on a slab. With that being said, in the past we have had very few contractors that would build on a crawlspace.  We are starting to encounter this more often lately. Has anyone on here formulated a checklist for inspection purposes for crawlspace/floor construction? I am having a hard time finding anything that regulates pier spacing when the perimeter wall is solid block construction. Pier and curtan wall construction requires 6' spacing but I am unable to locate anything that addresses solid wall pier spacing.


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## DRP (Oct 20, 2013)

The 6' pier spacing in pier and curtain wall construction is limiting the piers in that perimeter wall to a 6' spacing. If there are piers under the floor for midspan floor support in either pier and curtain wall or conventional crawlspace those piers are limited by soil bearing conditions and girder span limits, prescriptively they might be 14' apart, check the girder charts in R502ish


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## Francis Vineyard (Oct 20, 2013)

If you are asking what code sections requires the 6 ft. spacings in curtain walls is in section R404.1.5.3 Pier and curtain wall foundations item 5;

5. Anchorage shall be in accordance with Section R403.1.6, Figure R404.1.5(1), or as specified by engineered design accepted by the building official.

R403.1.6 Foundation anchorage. " and all wood sill plates shall be anchored to the foundation with anchor bolts spaced a maximum of 6 feet (1829 mm) on center."

Hope this helps with the answer to your question.


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## Architect1281 (Oct 20, 2013)

The minimum number of piers would be (1) WITH A REALLY GOOD ENGINEER .

Pier foundations and spacing are not prescriptive (IRC Construction codes for Dummies) and would therefore require engineering.


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## DRP (Oct 21, 2013)

> (IRC Construction codes for Dummies)


Not to be confused with the International Bilking Cabal


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## Builder Bob (Oct 21, 2013)

Avins said:
			
		

> I live in SC, we are using the 2012 IRC. I have been in building most of my life but recently joined the inspection department. In my years of building I only built spec homes on a slab. With that being said, in the past we have had very few contractors that would build on a crawlspace.  We are starting to encounter this more often lately. Has anyone on here formulated a checklist for inspection purposes for crawlspace/floor construction? I am having a hard time finding anything that regulates pier spacing when the perimeter wall is solid block construction. Pier and curtan wall construction requires 6' spacing but I am unable to locate anything that addresses solid wall pier spacing.


If you are in a seismic design category, the exterior wall should be continuous foundations with interlocking grade beams for interior piers.... I am unsure what seismic design cat your area in in...


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## ICE (Oct 21, 2013)

Builder Bob said:
			
		

> If you are in a seismic design category, the exterior wall should be continuous foundations with interlocking grade beams for interior piers.... I am unsure what seismic design cat your area in in...


I haven't heard about interlocking grade beams.  What code section is that please?


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## Builder Bob (Oct 21, 2013)

Oops.... Maybe I need to back track a little bit, I did not realize that the codes had changed for the IRC - it now states Engineering design is required. In the 2006, it had a general requirement for piers to be reinforced in the horizontal and vertical direction for a minimum of 48 inches........when the interior isolated piers were spaced at 48 inches and the code required all load bearing walls to be on a continuous foundation, , it just made it easier to pour a grade beam to join the isolated piers to the pier and curtain wall foundation to meet the requirement for a continuous foundation as the IRC stated.


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