# Foundation wall cure time



## Benjamin

How long would a concrete foundation wall need to cure before framing can begin on a 2 story SFR. Can't seem to find out a definite answer in the code book.

Thanks, Ben


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## Benjamin

BTW it's a poured foundation wall


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## mark handler

You won;t find a number in the code book.

What is the temperature?

Most concrete reaches ultimate strength in 28 days but around here framing starts in three to five days, slab on grade


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## Benjamin

mark handler said:
			
		

> You won;t find a number in the code book.What is the temperature?
> 
> Most concrete reaches ultimate strength in 28 days but around here framing starts in three to five days, slab on grade


Well the temp during the pour was prob around 55 and it was poured 5 days ago


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## TheCommish

at 7 days the cret shoud be 75% of full strenght


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## Kearney.200

Concrete usually reaches 75-90% of strength within 5-7 days @ 2-3 days it is still green but can be worked on these are rules of thumb and from my own past


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## ICE

If it gets broken, Shirley it was too soon.  If not, well then Shirely it wasn't.


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## mark handler

ICE said:
			
		

> If it gets broken, Shirley it was too soon.  If not, well then Shirely it wasn't.


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## mtlogcabin

There are a lot of varibles in that question. The concrete will easily support the dead loads after 72 hours. The problem will be with tightening down on the anchor bolts and any hangers, post and beam plates attached directly to the concrete.


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## mark handler

From some of the simpson anchor products....*DO NOT INSTALL IN CONCRETE THAT IS LESS THAN 7 DAYS OLD. Concrete is considered green if it has cured less than 28 days, after 28 days. ... The nut must be tightened .*


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## GCtony

Benjamin said:
			
		

> How long would a concrete foundation wall need to cure before framing can begin on a 2 story SFR. Can't seem to find out a definite answer in the code book.Thanks, Ben


Why are you asking?

The right answer would 7 days plus and/or not until you get the 7 day break results back form the engineer. The reality is the day after they strip the forms.  You're not pulling anchor bolts out of 2 day old concrete.  However I would probaly follow the simpson specs on their specialty stuff and wouldn't backfill for a week and the deck was on.


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## GCtony

Just for fun.... how long does a poured footing need to set before you can lay block?  Seriously!  Usually a lot of weight gets loaded on a reinforced footing the day after it was poured.


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## martinpgrant

As long as the engineer of record says it needs to.


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## demsley

It depends on the temperature of the weather and usually concrete getting strength within 5 to 8 days and for proper strength you should follow the instructions of the Engineer or project supervisor.


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## jar546

I have seen them strip the forms the same day, within just a few hours.


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## Uncle Bob

Mark is correct on the 28 days.  I didn't learn that doing building inspections; but while working as a construction inspector (roads, municipal water and sewer lines).  However, it is in the codes; *2009 IRC, Table R402.2, a.  Strength at 28 days.*


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## Uncle Bob

Uncle Bob said:
			
		

> Mark is correct on the 28 days.  I didn't learn that doing building inspections; but while working as a construction inspector (roads, municipal water and sewer lines).  However, it is in the codes; *2009 IRC, Table R402.2, a.  Strength at 28 days.*


Ok, to get the bold and underline to stop I had to start another post; lousy computer.  While working as a construction inspector we had a specialist do "slump tests" when pouring concrete.  Here is a good idea of what the requirements are; http://www.concrete.org/General/WTRF5.pdf .  I'd love to do final core test on foundations and make them rip it out and start all over.  When I first started plumbing; I was sent out one evening to do an underground (we called them roughs in those days, and above ground was called a top out; but I digress).  Anyway, they were wanting to pour that evening and helped me back fill so they could start.  The next morning I was sent to the same address to do a rough (top out).  When I got there about 10 am the frame was complete and the roof was on.  You good ole boy builders and contractors are causing numerous problems for new homes by not learning from knowledgeable sources; instead of "well that's we always did it, and we never had a problem".  Sure your long gone when the building starts to shift and the slab cracks and breaks up because you don't know or adhere to the requirements.  Us inspectors are no better; because even if we know we can't do anything about it. The builders run the show or they would have to wait for the foundation to fully cure.  I'd love to require a core sample at 28 days and watch these clowns rip the whole thing down.  Also note that R402.2 requires (excerpt) "Materials used to produce concrete and testing thereof shall comply with the applicable standards listed in Chapter 3 of ACI 318".  Uncle Bob


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## Builder Bob

Well it would depend - what is the psi design of the mix..... It wasn't unusual for highway department jobs to use 6000 psi concrete so they could strip the forms after the next day and begin placing forms for the vertical parts of the culvert.....some vertical walls were almost 30 feet in height. However, this is reinforced concrete with numerous re-bar and numerous tests on the concrete prior to placement - to include air entrainment testing , slump test, and break cylinders The contractor was allowed to strip and start forming the next day (12 hours set, however, before the concrete could be placed vertically, the break cylinders had to break at 2700 psi at three days. If they failed, they had to wait until the cylinder hit 2700 psi ( the old 75% rule I recall from an earlier post... )

The point is, testing and break cylinders should be required on SFR especially if in hit seismic, wind, or flood zones...... I have seen to many various bags of sakcrete sitting on a job site to know better.


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## globe trekker

Benjamin,

To obtain an accurate answer for your question, the company / RDP that designed &

mixed that batch of concrete should be contacted to obtain the actual time you are

seeking?

FWIW, around here the "house assemblers" are breaking forms off the next day

and starting to frame, just not tightening the anchor bolts.

.


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## khsmith55

Going to start a firestorm here. Peel the forms on Monday after a Friday pour. Not so much worried about a 15PSF dead load or even short term loading placed on the platform. My biggest concern is time of year.....you ask? Here in Colorado many foundations are poured in winter, no problem until the ground thaws and the building settles.


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## ICE

jar546 said:
			
		

> I have seen them strip the forms the same day, within just a few hours.


Same here and did that myself many times.  Of course it depends on what it was that was formed up but if you hit when it's still green, you can get all the wood out and clean the concrete from the forms without too much work.

I see it often where the form boards are embedded in the concrete and the wood stakes were snapped off at the concrete.


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## Pcinspector1

Day one pour, day two strip the forms and knock off the spreaders, day three waterproof and gravel the drain tile, day five rough-in the plumbing, day six get under slab inspection, day seven set the floor for pouring, day eight backfill if weather permits, day nine set I-beam and deliver first load of lumber, day 10 better be framing if your going to make $$$.

What was the question again?

pc1


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## GCtony

A framer always wants to know when the form guys will strip.  They are the ones that help you set the steel beam in the pockets.


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## peach

ACI 318 isn't particularly helpful, however ACI publishes 3 books I'd recommend: Guide to Formwork for Concrete, Hot Weather Concreting and Cold Weather Concreting.  ACI 318 6.2.1 says "concete exposed by form removal shall have sufficient strength not to be damaged by removal operation".

Comes down to the mix design, how long the concrete was in the truck, how much water they added.. yada yada. .. oh, yeah, and the schedule.


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