I am curious about how long the industry suggests vs. the actual time that is allowed for foundation to curing sufficiently before the start of multi-level framing. I may have mentioned this in the past, but I watched former install equipment for poured concrete walls with a day or two of the footings going in. This might be something to raise an eyebrow about, but what got both eyebrows raised was that in under ten (10) hours after walls got poured the steel forms were removed and framing started the very next day.
No, neither of these observations were exceptions, but rather very common practices I observe in my subdivision. If you were building your own custom home, would you wait longer? For reference, I am ~45 miles outside of Atlanta, Georgia (Exit 120 on I-85). Being that I work second shift (4PM-Midnight), I get opportunities now and then to observe construction in my subdivision. I think after 6.5-7 years they are finally about half-way through the development, lol.
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on foundation. next day is fine to lay block, because its a mass. On slabs I like to see its covered with plastic and kept wet for seven days. But time is money
footers to crete walls ooner is better
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Engineering dictates that concrete reaches 65% of its ultimate strength in 7 days..That's when cylinders are tested to see if/how the concrete is curing. The ultimate strength will be reached in 28 days..
Engineers would love it if framing (structural steel) would wait the 7 days..and that is why engineers are not construction managers..Framing will generally start within 2-3 days..
In residential...we usually start stripping the forms the day after the pour..by the time the footing drains and waterproofing are done, there is a 2-3 day lag time and the framers can start...
"concrete reaches 65% of its ultimate strength in 7 days..That's when cylinders are tested to see if/how the concrete is curing. The ultimate strength will be reached in 28 days."That would be more or less, depending on temperature and the mix.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
down here where its warm all the time 90 % of concrete reach 100% strength in seven days. but that only because we got some good mixes.. 2+3=7
"100% strength in 7 days". OK, but the concrete has to be a high early strength mix (which can get expensive and is also somewhat brittle), or you have low expectations. I can ask for a 4500# mix and easily expect 3000# in seven days, but if I ask for 3000#, I won't get 3000# in seven days. Even under controlled lab conditions, a standard mix (meaning no admixtures) will not hit full strength in a week. Maybe 80-90% if you're really lucky.
since this is for a newbie who needs a day job...let's remember to define what that percentage is a percent of.100% of desogn strength is different from 100% of final strength. Because the reaction theoreticly never ceases, the mass of material continues to get harder as time goes on. Forty or a hundred years from now it will achieve 99.98% of its final strength which will be a good deal stronger than whatever its design strength is, which can come to be sometime between three and thirty days after it is first mixed depending on the mix and the temperature. As you point out, the temp is less of a considerable variant for you in the south than it is up here so those rules of thimb are more appropriate.
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I read that the so called concrete of the pymids area around 15,0000 psi. 2+3=7
Now THAT'S cured!aren't they limestone? I know that it is fairly soft and easy to chisle when it first is quarried, but then exposure to thge oxygen makes it react and harden over time
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Also, is it common to add something to a mix that would cause it to cure faster? Also from my observations they do nothing to prevent accellerated surface drying, which from what I've learned on FHB (blaming you!) can lead to surface cracking, much like a dry mud bed. They do not typically cover the pour on slabs/footings, nor do the keep it wet.
Anyway, I just wondered is a 9' tall 10" thick poured concrete wall would apply sufficient mass to a 10-12-hour cured footing is acceptable for my climate. I'll stop being curious now since some think I need to get a day job (and evidentally stop posting).
I'll stop being curious now....
Easy does it. Sometimes a tough crowd here. I've even been accused of that.
Most of what I know about concrete is what I read in trade journals and building a couple of cast-in-place houses with heavy roofs. Accelerators are best avoided. Stripping the the day after the pour is only for economic benefit, not the concrete. But it works well enough for the practice to be common.
I leave my forms on for several days, but it's of no economic consequence. Pretty sure what you're seeing: A) works there- or it wouldn't be common, and B) keeps the cost down. Metal forms are expensive. They aren't earning any money shading concrete.
PAHS Designer/Builder- Bury it!
That would be more or less, depending on temperature and the mix
And the contract, too. Not unusual to test at 7, 14, & 28 days; four weeks being the 98% strength point, mostly. That's why there's supposd to be 4 cylinders cast.Occupational hazard of my occupation not being around (sorry Bubba)
That's why there's supposd to be 4 cylinders cast.wrong answer.4 clyinder are cast because there is a 7 day break, two 28 days break and a hold clyinder that kept till 56 days. 2+3=7
4 clyinder are cast because there is a 7 day break, two 28 days break and a hold clyinder that kept till 56 days
Ok, found the ancient spec reference and sent it to digital doom <g>.
I was also misremembering that one was held for posterity (lawyer bait), and forgot the double bust at 4 weeks.
I'd written (and or edited) that thou shalt make the holy cylinders to be sent off to thine minions at the testing laboratory so long ans insomuch as they do not reflect poorly on the archy in his inhumility and the owner can keep writing the checks to pay for the testing lab. Verily.
(Edited to have "thou shalt" read "you will" <g> . . . )Occupational hazard of my occupation not being around (sorry Bubba)
it just what I do, daily, every day, rainy day, cold day, hot days, dark days, foggy days, for years and years and years, break concrete.. 2+3=7
<<it just what I do, daily, every day, rainy day, cold day, hot days, dark days, foggy days, for years and years and years, break concrete.>>Better than making little rocks out of big ones. <G>A king can stand people fighting but he can't last long if people start
thinking. -Will Rogers, humorist (1879-1935)
every day, rainy day, cold day, hot days, dark days, foggy days
You probably even have insulated test cylinder forms for when it's right cold out (our local lab used to, but I don't know if Manny, the good tech still works there).Occupational hazard of my occupation not being around (sorry Bubba)
i think you need a day job..... with plates down and spreading the load... you standing on your toes are putting more pressure on the slab than the framing...
p
"I think you need a day job .....
Why? What have I done that was so wrong in posting this out of curiosity? I know, consumers should be ignorantly stupid about all things and assume like all good Democrats that its done 100% right 100% of the time.
"I think you need a day job .....
Why? What have I done that was so wrong in posting this out of curiosity? I know, consumers should be ignorantly stupid about all things and assume like all good Democrats that its done 100% right 100% of the time.
Yeah... that did sound harsh.... guess i'll stand by it
p
"I think you need a day job .....
Why? What have I done that was so wrong in posting this out of curiosity? I know, consumers should be ignorantly stupid about all things and assume like all good Democrats that its done 100% right 100% of the time.
Yeah... that did sound harsh.... guess i'll stand by it
I think you should just promote an environment where those not in the business of construction are banned from the forums. Banning HO's would probably suit your Internet personality more appropriately, but I wonder how its hurt your business.
I'll begin each new thread I post with 'HO' for homeowner, that way you will not waste your time reading my posts. And in return, please post your business' name so HO's will not waste your time in person with business.
Carry on.
hey nuike i think the abbreviation is homo,just so it doesnt look like you just got hereDue to recent budget cuts the light at the end of the tunnel will be turned off until further notice.
Nuke,
For someone who is just expressing a little curiosity, you sure are having a bad time all over this forum this week.
Relax, I suspect that the winter-time-blues are getting to this bunch of ruffians we have populating BT. Their attitudes will improve with the weather.
SamT
I carved out this nice little world.... I only build for me...my projects... on my land... my designs... I'm my only customer... most people wish they had 10 customers like you... the problem is they have 100... which led me to my current form of work...
I didn't want to get on a rant... but I'm cheap so for your 2cents worth you get mine...
You already had an opinion when you posted... "i work nites so i get to see what really goes on" is basicly what you were say'n and I'm sure if you have anyone left who will dine with you ..you let em know "all you know" you just wanted someone to confirm that they are building on "uncured concrete" well captain... they are and if they built on it 30 days from now or 2 years from now it still wouldn't be "fully cured" the deal is you stand'n on one fat toe on that concrete is putting more pressure on it than a 2 story wall would... BUT i'm sure you'd be the first to "inform" the new homeowner "hey if ur concrete ever cracks I know why" I also know were they used 2 nails vs 3 in a stud and if you ever want to know anything about ur house...come ask me cause i saw it be'n built...i work nites.....
P
oh and the HO is a nice idea and i thank you
On our church project a couple of years back I was putting down mud sill at 7:30 AM, when the foundation had been poured about 7:30 PM the previous day. Was careful to not tighten the bolts too tight.
Really, for framing you don't need much strength. The structure doesn't acquire that much weight until you start rocking it. The only important point is to avoid localized stresses (like tightening the anchor bolts) that would tend to crack the concrete.
And forms can be pulled off as soon as the concrete will reliably hold its shape -- four hours is sufficient in many cases. Of course, leaving the forms on longer helps curing, by holding in moisture, but there are other ways to do that.
happy?
And, with regard to pouring concrete walls within two days of pouring the foundation, keep in mind that many large structures are constructed with a "continuous pour" technique where forms are leap-frogged up the structure and there's no delay between pours.
happy?
Dan, that is a very good point. I had forgetten about continuous pour construction.