Thank you all for your input. I'm not sure what I'll do about this. I really like this builder and his houses are extremely well built. He's been building for 40 years including lots of mountain homes hanging off of the edge of a ridge. I will be building my first ever house. If I choose him, I may just let him do it his way.
He actually doesn't have much work right now, so he's not suggesting this as a stalling tactic. He got his start building lake dams and such, so he is a stickler for details -- you really don't want your work to fail when you're building dams! The way I see it, it might not help but it couldn't hurt. But when you are talking about walls poured on top of footers, I'm of the opinion that what matters most is having plenty of the right size rebar embedded and sticking out of the first pour so that there is a strong mechanical linkage.
If you have that, then I think that the benefit of any improved bonding that may occur by pouring on top of green concrete is in the noise level. I have a neighbor who runs a large commercial construction company and they pour quickly when they have to, but wait longer when they can. I think this is an issue on which reasonable people can disagree. I prefer my first pour to cure and strengthen longer than a couple of days.
That's just my opinion. We were always taught at least a week, I just simply stated that 28 days was extensive or extreme period before the walls pour. I also agree with hillbilly that he should go with the builders m. The big news was that the elevator shaft was being done in a continuous pour.
They had concrete trucks and a pumper going around the clock. Why was that? When you are bulding concrete up vertically, do you want it all to be about the same "age"? Sorry to sidetrack the conversation, but this is such a good discussion and the question popped into my mind. Hi Buckhead, because it's a continous pour, it gets poured out non-stop.
You can relate it to your build. Your footers are poured out, then the walls will be poured out as a "continous pour", only on a much more minor scale than the awesome elevator shaft project! It's all relative. I would have liked to see the method they used to vibrate the crete on that project.
That alone would have no doubt been impressive. A continuous pour avoids "cold" joints in the concrete where the concrete does not bond. Why that was important is hard to say without knowing the design but I would guess that the lateral force wind and earthquake resistance of the structure relied primarily on the strength of the elevator shafts.
There is nothing magic about 28 days. It's just a standard time period used for the testing of concrete samples to determine if they have met the design specification. Building Codes nor Standard Engineering Practice consider concrete or poured masonry products to be 'cured' until at least 28 days after pouring.
While it may be 'common' to construct block or poured foundation walls on concrete footings that have been allowed to sit for days, NO respectable builder NO respectable architect FWIW, I usually end up with 10 days between footing pour and walls. After three days, the footing boards are stripped. Then the municipal building inspector must okay them. Finally, the forms are brought in and set up and it's ready for pouring.
Block walls go a bit faster. They did this and setup the floor joist and then we waited about 2 weeks for plumbers to run their lines and get floor insulation in. Subfloor went in and we started framing probably weeks after we removed the forms.
Residential work does not load concrete work very heavily in most cases. A common exception is slab on less stable earth. Bond beams, post tensioning, and other techniques are then used to create a monolithic slab that will act as a single piece and uniformly spread loads.
Most of the size is for load spreading on the ground, and the ability to neglect point loads introduced by the house framing. By making the foundation stronger than needed, the load concentration produced by large openings in the framing is ignored. Even basement walls are not that heavily loaded by backfill.
The tipping problems that occur are from a lack of lateral resistance before the floor joists are installed. I have seen basement walls fail, but they had enough curing to fall over as a unit after a fracture near the middle. Adding floor joists before any back-filling has been SOP for many years, yet occasionally seems to be ignored. I am a structural engineer and I have to chime in Pouring the walls the next day is absolutely fine. Concrete cures depending on the mix, ambient temperature, water content As long as the cure rate shows that the concrete is strong enough to handle the load the next day it will be fine.
In fact, applying force or mass--i. BTW concrete never actually completely cures year-old concrete is still getting stronger I'm always amazed. And silently smug when I see a collapse. I used to delay backfilling till the roof was framed and sheathed. But then I have persistent nightmares that the homes I build will collapse in on themselves without warning like something out of Poltergeist. Concrete does not actually harden by "curing" nor is there any point in time when concrete would be considered "cured.
Concrete naturally hardens over time by "hydration", the chemical reaction between portland cement and water in the concrete mix. In the case of a residential footing curing might consist of simply covering the concrete for 3 days. In any case the curing procedure would not normally continue beyond 5 or 7 days depending on the temperature of the air. As long as moisture and a favorable temperature are present for hydration of the cement, the strength of new concrete continues to increase long after the early curing phase and the 28 day mark.
Since the actual strength of the concrete in a residential footing is not particularly critical, testing is not required so the 28 day mark has no practical relevance in the field.
In fact, if the concrete hasn't reached the minimum strength required by code in 7 days, it's unlikely to get there. The IRC requires a concrete footing to have a minimum compression strength of 2, psi which is a low value and easy to achieve most specifications would be higher.
I won't characterize that earlier claim since it speaks for itself. As far as "respectable" architects are concerned, I have linked my grad school textbook as evidence of my training in this subject, although I would normally defer to an engineer in professional practice. The subject at hand is briefly discussed on page 5. Of course, my book was a much older edition.
It is important to understand that "curing" is an optional construction procedure rather than a physical state to be achieved. The use of phrases like "the concrete is cured" is shortspeak indicating that the desired period of moisture control is over. The design strength is just one of many variables considered in the selection of a curing method and time period. I once had a bad batch of concrete poured in the mat foundation of a large hospital addition.
Unfortunately, it was an all day pour so it threatened to delay the project. In a big meeting of all the involved parties the concrete testing engineer announced that there was enough fly ash in the mix that steam curing might bring it up to the design specification. I had done an existing conditions survey of the adjacent buildings as part of the architectural design process and told them there was an unused steam line immediately adjacent to the bad pour.
People flew out of the trailer to tent and steam the concrete mat. When the test results came in the ready mix owner was so choked up he couldn't speak. Now there is someone who is unlikely to bad mouth engineers and architects. Here is a link that might be useful: Concrete design textbook. So doing research to determine an effective time short of forever for measuring the strength of concrete is arbitrary?
Variation will occur during assembly away from the ideal methods. We use the derating of absolute values to account for this. Choosing 28 days is far from arbitrary, but based on much research to establish a reasonable time based on mix and applications. My point was that the 28 day mark represents a testing standard based on professional concensus rather than representing the point at which the concrete work can support a load. To say a footing cannot be partially loaded before the 28 day mark indicates a staggering misunderstanding of concrete design and construction.
At any rate, it should be clear that the contractor in question either has another reason for delaying the OP's project an additional 3 weeks or he doesn't know what he is doing. Either possibility would concern me greatly. This isn't rocket science; it's just a house footing. Excellent discussion. Who the heck is Manhattan42?
He writes as if he was a pro but says things that don't make much sense. I've built 2 houses and the builder of the first did want to wait 2 weeks crawlspace. This was a tract build. Flash forward 10 years and the custom builder just kept on trucking basement. He was also the one who explained the concept of purposely slowing the cure with water The common assumptions about concrete curing are interesting.
Houzz TV. Houzz Research. Shop Featured Holiday Categories. Home Decor. Holiday Decor. Christmas Trees. Holiday Lighting. Gift Cards. Building a Home. Have not discussed timeline with my builder yet, wanted thoughts from here.
Email Save Comment 4. Sort by: Oldest. Newest Oldest. Like Save. This subject was discussed back in Like 2 Save. Related Discussions How far apart to hang double chandeliers over a 14 foot dining table Q. There are no rules for this, but I would recommend that you use the 10 foot dimension as your base Place the two chandeliers 28" apart and this will leave 18" on the ends when you have the 10 foot table When you have the 14 foot table you will have 42' on the ends This will look good How large a tv to put into foot-of-bed furniture where tv will pop up Q.
With the tv that close, consider a 26" or 32" at the most. How much do porches a sq foot cost Q. I live in the Spartanburg, SC area.
My question is how much when trying to plan my budget do I need to expect to spend on my porches per square foot? It is probably better to put the concrete into the round tubes you have secured in place using shovels because concrete is heavy and it is quite easy to dislodge or move the tubes and misalign the footings. Most premixed concrete suppliers will charge you extra if it takes too long to get the mix out of the truck so a quick careful placement of the concrete is essential.
When you are filling the tubes fill to about halfway and then use a piece of rebar to consolidate the concrete to get rid of any air pockets or voids. Fill the rest of the tube until it is slightly overfilled then use the rebar again to consolidate the concrete you could also tap the outside of the tube to consolidate and top up with more concrete and smooth the surface with an angle towards the outside to help water runoff.
Now is the time to insert and align the brackets that the posts will sit in if you are putting the footings in before you build the deck. If on the other hand, you are putting in the permanent posts after building the deck then you will already have the brackets fixed to the posts and they are aligned in the centre of the formwork tube and it is a simple matter of pouring the concrete around them.
Concrete contains lime and can be an irritant on your skin so I like to were eye protection and waterproof gloves when I use concrete. Some waterproof footwear is also a good idea and make sure you wash everything that gets concrete on it before it has time to dry a brush to scrub all your tools and equipment is a good idea. Here is a link to help you calculate the amount of concrete to order remember a little extra is better than not enough.
A hacksaw or utility knife to cut the lengths of formwork tubing andbe sure to put the uncut end at the top it will make a neater job. Wheelbarrow s to move that concrete and remember its heavy so test to see how much to put into the barrow before you try to move it. So frustrating to go to all the trouble and work to pour a really good concrete slab only to have it crack for no apparent reason so what to do?
Why does new concrete crack and how to prevent The decision has been made to put down a new driveway to have enough room to store your RV at home so that it is safe and any maintenance can be done and it could be used as overnight accommodation Skip to content. Before you go, check this out! This is what the Civil Engineering Department wrote about concretes properties and curing time.
Or you could build the deck before you make and pour your concrete footings By building the deck using temporary posts to hold up the frame while you build it.
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