Planning to place footings and concrete wall in mid November in Delmar, NY, about 6 miles southwest of Albany, NY.
I’m reluctant to use calciium as an accelerant because of its alleged shrinkage-crack-inducing tendencies and the potential for accelerated re-bar corrosion. I admit I have never witnessed these, just heard about them. I also don’t want to wait until spring to start this project.
For those living and placing concrete in cold climates, what have you experienced?
thanks in advance.
Lek
Replies
Let's see if we can get Gabe to weigh in on this one.
In the meanwhile;
1) Do not let the ground freeze. Cover it now.
2) There are some good non-chloride accelerants available. Be careful, some are sunlight-activated and will do you no good on a grey day. Don't ask me how I learned this.
3) Go with air-entrained if you will not have this concrete in conditioned space before hard freezing temps hit.
4) High early strength with the air entrained can give you a little more safety factor.
5) Buy or rent plenty of concrete blankets and use them.
6) Talk with your batch plant about their cold-weather options. Your batch plant guys are generally pretty darn good at what they do, and know your local conditions. They may suggest hot water, heated aggregate.
7) Make provisions to care for your crew if it will be really cold. Have a few extra guys on hand ready to work, hot drinks, and food. You'll get better work from more comfortable (or at least less uncomfortable) workers.
Let us know what you decide and how it goes, eh?
DRC
Dave you and the others have covered most of the issues. November in this climate is not severe yet but as you pointed out, it's what comes afterwards that counts. How soon will the foundation be backfilled, heated/protected is just as important as cold placing proceedures. Always try to eliminate the forces that will stress the foundation and half the battle is won. Frost will crack any wall, regardless of the structural design if left unprotected.
Gabe
Lek:
Mid November shouldn't be a big deal but some cold weather things to remember:
First, dig the hole as close to the pour as possible.
Second, get a whole bunch of hay and place about 8"-12" in the hole right after you dig.
Third, cover the footing with either the hay or crete blankets.
Fourth, form and pour in one day if possible (it's really hard to cover the footings and the forms. Most DIYers will leave the top open and get frost/ice/snow into the forms.
Fifth, call the plant and tell them what you are trying to do. Let them recommend the right mix for the weather. That is their job, not yours.
Sixth, cover the footings with the hay and the top of the wall with blankets (if it's below freezing).
Seventh, wait at least 24 hours to strip. Curing is an exothermic reaction. It will generate enough heat over the first two days to keep itself from freezing with the blankets.
Eighth, don't even think about using tar to waterproof the walls when it's cold. Sub it out to someone with a spray truck. Call the plant or look in the yellow pages.
Ninth, DO NOT break off the ties from the wall for at least a week unless you are using kinked ties (that won't twist).
Tenth, call the Davidson brothers and let them do it. They live right near you. They are on Weisheit Road in Wemple. Tell them Mike Ouellette (John Ouellette's son) told you about them.
Eleventh (and most important).....pour ten foot walls! You will send me an email in two years thanking me for this. There is nothing better than having 8' of usable ceiling space in your basement with the mechanicals all stuffed up in their.
Twelvth, pay extra for the new all vinyl basement windows and get the biggest you can place considering elevation.
Thirteenth, plan accordingly for beams. Don't bother with the damn columns. Get some steel in there for a clear floorplan in the basement (again you'll thank me).
Mike O.
Lek,
Both Mike and Dave have good advice for you. The most important are: 1. Never pour on frozen ground. 2. Use air entrained concrete (6% +/- 1%). 3. Batch plant will provide "winter service" but will probably charge extra. Resist the urge to skimp here. 4. Keep the mix around a 3" slump and vibrate well. 5. Cover with blankets and leave covered as long as you can. (3-days if it is really cold.) Concrete curing is exothermic (gives off heat) but the mass of your pour is not that great and once the initial heat is gone the curing process will slow and subsequent heat re-generation will be marginal. 6. Don't stick an unvented salamader or bullet heater under the blankets after you strip. The CO will react with the fresh concrete and form calcium carbonate leaving a chalky and weak surface. They're also a fire hazard. If you want to increase the performance of your insulation, lay heavy mil sheet poly over the forms then cover with blankets. Keeping the wind out and moisture in will aid in early curing and heat retention. 7. Concrete must reach at least 600 psi to resist the destructive effects of freezing. In addition, the colder the concrete gets, the slower the curing process. Take time to properly cure upfront, then you will be able to load the walls earlier, since I assume you're planning to deck and frame as soon as possible.
Eric
To all:
You guys are definitely alright. It's mind-blowing to have all this expertise so readily available and so willingly offered.
I'm caught in a housing-time-crunch problem and have to get going this year and be out of my current place by next summer. Are concrete form blankets something I can rent? The concrete contractor (David Davison, is this the guy you know Mike?, he currently lives in East Greenbush)) said he places concrete through the winter using calcium and heated water and hasn't had any problems, whatever that means.
Last Q: I was plannning 9 foot walls and I would like to know if the concrete is normally guided down to the bottom of the form with a hopper or is it just dropped from the top of the form, with no concern about aggergate segregation? I'm not trying to be "anal" about this , but concrete is one mis-used and abused building material.
Thanks again.
Lek
Concrete shouldn't be allowed to free-fall over five feet. Use a hopper and a tremmie or if you're pumping, lower the hose down into the forms and come up in lifts. It is not "calcium" that is added to concrete it is calcium chloride (salt). You know what salt does to steel right? I assume this guy doesn't use fiberglas reinforcing rods. He's never had a problem means he's never had a call-back due to this issue. The degradation takes time; years. But it happens just the same. Put salt on your fries, not in your concrete.
Eric
If you can't buy or rent the masons blankets, just putting a layer of plastic down will keep the ground about ten degrees warmeer than surronding. It slows radiant cooling and keeps the earths heat right there.
I have some of the old bubble float blankets for swimming pools. Using that and a plastic cover, I've kept the frost out with temps down to 15° for two or three weeks.
My concrete guy likes to use the calcium chloride, not in the mix, but to spread on the ground just prior to pouring a pad. It reacts with the moisture in the ground to produce heat and wram the ground right under the slab a little. I don't know how effective that is really but I have no problems with his work..
Excellence is its own reward!
Kinda hard to pour nine foot walls because most systems are 8', 5'4",4' & 2' systems. You will end up with a net of 9'8" with 10' of panels (8' + 2' stackers). That results in a 9'6" ceiling height in the basement after you pour the floor over the footing.
You should be able to rent blankets. Find an equipment rental place that has concrete stuff for rent (power trowels, chutes, crete saws, etc) and they should have them.
David is the guy. I think his brother lives in the house I described. They are great guys and were my father's best customer (my dad used to sell supplies to concrete contractors). Unfortunately, my father passed away while having coffee with David's dad. Their family was great to us.
Calcium Chloride is fine for use in residential walls. I have poured several hundred residential foundations in CT and very, very few were spec'd with rebar (but we poured 10" walls almost exclusively. Yes calcium chloride is not nice to steel but I wouldn't worry about it. Your biggest fear would be the tie but you will be sealing that on the outside anyway.
As far as the free fall and sepration of aggregate; use a 7.5" crete shovel on a tie about half way down the wall to break the free fall. As soon as you have two to three feet in the corner, you can take it away. A six foot drop into the concrete is fine. I'm a big fan of vibrating but at a minimum, beat on the bars of the panels with a nice 22+oz hammer to get rid of some of the air.
I really can't say it enough...foundations are more complex than they look and should be left to the professionals. I'm not saying crete guys are rocket scientists but there is a considerable amount of capital equipment AND EXPERIENCE that is required to make a straight, square and level wall. Mistakes are very, very, very costly and are not easily undone with concrete.
Spend the extra $$ and get the job done right. Again, you'll thank me when you go to lay your sill.
Mike O.
"I really can't say it enough...foundations are more complex than they look
and should be left to the professionals."
If ever there were advice worth listening to, that was it.
The best way to save money on a foundation is to hire a pro that you trust and stay out of the way.
DRC
Mike,
The house plans call for a 10" wall plus a brick-ledge. How do you normally create the void for the brick-ledge? Also, the contractor told me he has 9' panels. Is that the panel size used for an 8' wall, when in fact he should be doing what you suggested: stacking 8' panels on 2' stackers?
Lek
He may indeed have 9' panels if he has a non-popular panel system.
We had brickledge forms prebuilt (out of MDO) that slipped into the top of the foundation. I've seen people use foam 2-3" foam as the brickledge though.
Hope we've been helpful
Mike O.
Mike and all,
Yes! you and the rest have been very helpful. Nothing like getting advice from people with real-world experience and knowledge.
Resolution: I'm going to skip the calcium chloride, request the heated water, six-sack mix and use insulating blankets and the taller wall forms. Oh, almost forgot: gallons of hot coffee for the concrete crew!
Lek
Just to let you know...now you'll have an 80 degree day when you pour!
Mike O.
To roughly paraphrase Martha Stewart: that would be a good thing!
Lek
p.s., You may have already mentioned it, but, where are you located?
To paraphrase Martha Stewart....I'm innocent
Gabe
To paraphrase Martha Stewart, " how'd I get so fat, and will I be the dike or the fem in jail"?
Be well
Namaste'
andyIt's not who's right, it's who's left ~ http://CLIFFORDRENOVATIONS.COM
Seymour, CT
"You guys are definitely alright. It's mind-blowing to have all this expertise so
readily available and so willingly offered."
This place strikes me the same way.
DRC
Lek ...I was considering doing the same thing here on LI in NY in Jan but from what I've just read I think I'll wait till the end of March/April. I have two large areas that I will be adding onto my house. Sounds like it'll cost more in the long run with all the time in precautions, slower man power and extra work then its worth to me. I'll have plenty to do inside the existing for now anyway....Glad you started this thread. Thanks and good luck. Let us know how it goes...brrrrr......
Be well
Namaste'
Andy
It's not who's right, it's who's left ~ http://CLIFFORDRENOVATIONS.COM
Edited 10/14/2002 9:01:29 AM ET by Andy Clifford(Andybuildz)
andy.. in our climate. (Rhode Island ... Long Island ) . i wouldn't sweat it until after Thanksgiving.... we pour all winter , but after Thanksgiving you can definitely run into some cold snaps.. before that .. no problem...Mike Smith Rhode Island : Design / Build / Repair / Restore
no expertise from me... not my area. this footnote/question is actually more pertinent to slabs, but i'm wondering what the experienced ones here have to say about fibrous materials being added to concrete in cold weather pours (of any kind).
was done for my driveway installation.
brian
Fiber reinforcing materials are great. They do nothing for cold weather pourability or curing but help with the strength of the concrete. I remember seeing a booth at The World of Concrete in Vegas about a decade ago and that stuff has an incredible effect upon the strength of the concrete.
Mike O.
How about using ICF blocks? Self insulating to keep the concrete warm, and you end up with a basement wall that is already insulated and ready to finish.
They don't have a good following up here in the Northeast. I have spent a good deal of time on several manufacturer's websites and they seem to use them heavily above grade. The actual concrete is only 4"-6" thick. I would be really concerned about pouring a full height basement with such a thin wall. I don't think it could withstand the shear force of the backfill material (esp. when that fill is wet). I'd rather have a nice 10" wall under my sill.
When I build a garage/workshop out back I am going to look into them further since that is just going to be a 4' frost wall.
Mike O.
I've poured 10' high basement walls with Smartblock by Conform..
Full 8" wall. Ladder brace on top. brace the corners. pour on...
I did use them on my house for the 4' frost walls worked great.
We use hot water and calcium up here in Colorado.
Mike,
Check out some of the engineering values on Reward. I went up about 11' on an earth-sheltered solar home a few years back, I guess about 9' of that was underground. It was designed to take some pretty good equivalent hydraulic as I recall, anyway, it's still there and looking good.
If you go with #5 rebar 2' oc vertical and #4 in every horizontal course (16" oc) it's amazing how strong this stuff is.
I'll finish three houses this year with Reward from footing to top plate, and hpe to do at least as many next year. I wouldn't hesitate a bit to use this for basements.
For a guy like you who obviously really knows concrete, this material would be a slam-dunk.
DRC
I used Superform blocks on my house, they are made here in Canada so they were easier to get than other manufacturers. 4' long 12" high, 12" wide with a 6 7/8" concrete core. They have straights, 45 degree, brick ledges and a top block that flares the concrete out to 10" wide. Very reinforced with webbing in the blocks and corners.
I did my frost walls and basement with it, 9 foot basement with 8' of backfill, you just put more steel in it. I set horizontal every block , doubles on the bottom and top, and vertical every 16".
They have a bracing system that you can rent (or buy if you want to get into it ) , it includes a scafolding system to make it easy to pour. Blocks go together like lego, and if you have designed with them in mind you end up with very few cuts.
My wife and I put up our walls in a week, working the weekend and days. that was longer than it would normally take but we had a couple of off angle walls that had to be cut and fit so it took longer. Not to mention that this was the first time we had done this so we checked everything 3 times before we cut anything.
Robert
ICFs actually have a growing following in the northeast. I think much of the resistance to them comes from concrete contractors who have a large investment in their forms. I can't blame them for not want ting to let thousands of dollars in form investment sit idle while the crete gets done with out it.
As to the thinner walls, because the crete cures inside the foam to retain the heat and moisture, and because it has snaps to control exact placement of the rebar, These walls test out stronger under tension than the average8" wall with bar.
To pare a phase of Martha Stewart, "Well now isn't that something!" typed slowly to simulate her monotone..
Excellence is its own reward!
Actually Piffin, it's the opposite. ICF's test out weaker.
Gabe
ut ohIt's not who's right, it's who's left ~ http://CLIFFORDRENOVATIONS.COM
Whatchew tryin ta spell dere bro' ?
Betting Gabe and I are both left standing, since we be both on the right. Now Mike - He's left at the beginning, but we don't hold politics against min either, since he's right..
Excellence is its own reward!
OK, I'll bite, and willing to defer to my betters but tell me how. My stuff was what the sales reps provide. There are different kinds of strength and ways of measuring it and different forms have different shapes so all is not equal - any more than every on site pour gets the same mix.
I'm supposing that maybe they use testing of compressive strength due to the hard surface density measured in PSI but the more important strength in a wall is in the tensile strength? which you refer to?
Out of curiousity, would a ten inch wall with no rebar or an eight inch wall with rebar placed correctly be the better at resisting lateral pressure?.
Excellence is its own reward!
Figures can lie and liars can figure.
What it boils down to is that you're limited with icf's to the kind of concrete mixes and slumps that you can use.
I can form a wall to withstand proper vibration and use a low slump high strenght concrete. I can place the steel where I want and as much as I want. I can inspect my work and repair/patch any voids. I can, in the event of an error, epoxy a crack and seal it. I can do all the benefits of icf's without the limitations. I can pour a foundation every day behind a footing crew better and cheaper than any icf crew. I don't have to pay royalty fees on proprietary forming systems.
An termites aren't a problem.
Just a few of the reasons that I consider icf's an interesting product for a limited niche market but not something that I would promote as the answer to the construction industry's woes.
Gabe
It sounds like what you are saying can be summed up as - Amoung the thousand of variables affecting concrete strength, proper mixing and placement is one of your highest concerns and that this is harder to control and inspect when using ICFs, right?
I'm not rying to argue here, just pull out practical information. I know about care in placement. I also know there are too many "concrete conmtractors" who are laborers with forms and don't understand the first thing about the chemistry, curing process, strength, or even what a level is in some cases.
So from a practical viewpoint, for me here where it is hard to get crete people to the island and crete is approaching a hundred bucks a yard, delivered, I think I can do a better job with my people, closely supervised using IDFs than a rawhide outfit slopping something together and "forgetting" to bring along the rebar..
Excellence is its own reward!
Part of what I was saying is that but the main point is that I can achieve a better foundation with standard forms than anyone else can with icf's. Not because I'm smarter or better but because I have the advantage with standard forms to be flexible with my mixes.
ICF's will not prevent concrete walls from freezing 7 days after the pour unless the foundation wall is heated.
ICF's will not prevent a concrete wall from heaving if placed over frost or frost is allowed to get under it.
ICF's do not give you value for your dollar. The exterior layer of foam will deteriorate long before the mortgage is paid.
Like I said, ICF's have a market place niche but that's all folks.
Gabe
I really hate metric
BB
Whats metric? lol
aIt's not who's right, it's who's left ~ http://CLIFFORDRENOVATIONS.COM
I'm with you all the way, Brownbagg. I'm absolutely certain that's important information that Gabe provided, and in fact I have been wondering about that stuff for years.
Now if I can just figure out what it means. <G>
Off to get the calculator.
DRC
I'll take the 10" wall with no rebar!
Sorry, but that's what I have under my house. Mine was set and poured by relatives for material cost so I could have spec'd it any way I wanted. As a matter of fact it would have been cheaper to do the 8". I would have paid nothing for the bar and chose not to put it in! My father's 25 years of industry experience are the only reason I chose this. After 7 years, I have zero cracks!
Mike O.
Edited 10/21/2002 7:39:17 PM ET by MIKEOUCH
In what kind of soils?
With all of our expansive clays and freezing, we consider it insane to leave rebar out. It's probably fine in more gravely or sandy and with less freezing..
Excellence is its own reward!
I live in CT. I have what I will describe as rocky soil, no clay, decent drainage. It does not hold water all that well which is good for me!
There are parts of the state that I have worked in that are all river silt (think quicksand when it gets wet). We poured the same thing there.
Mike O.
Hmmmm, what I have read from my manufacturer, and the Portland Cement Association is that because the concrete in an ICF cures in its form it reaches a much higher strength fibished strength than concrete which has the forms stripped off and then cures in air.
Around here there is a building boom going on which means that unless you want to pay a lot of extra money your forms are going to be stripped 24 hours after the pour, that the amount of rebar is minimal and then insulating the concrete in cold weather after stripping just is not going to happen. All of which made ICF's a much easier decision.
Robert
Before I can interpret the answer I have to examine the question.
Which is best?
Poorly mixed and poured concrete in standard forms or properly mixed and poured concrete in icf's?
FYI
Factors Affectin Ready Mixed Concrete.
1. +5L water = + 20mm slump
2. +1% air = + 20mm slump
3. +15 Min. overmixing = -1 MPa
4. +10 Min. overmixing = +1 degree C
5. +1 degree C over 25 C = -0.5 MPa
6. +20 degree C " " = -10 MPa
7. +10 degree C " " = -30mm slump
8. +20L water = -5MPa
9. +20L water = - 32kg of cement
10. +32kg of cement = +$2.00
11. +32kg of water = +$2.00
12. +1MPa = +5kg cem (20MPa concrete)
13. +1MPa = +10kg cem (35MPa concrete)
14. +10 degree C = +5L water to maintain slump
15. +1% extra air = -1.4MPa (20MPa concrete)
16. +1% extra air = -2.8MPa (35MPa concrete)
17. +7kg ice = -1 degree C
18. +7kg ice = +0.5MPa
19. +7kg ice = -2.5kg cement
20. +1 minute truck time = -$1.00
per cubic meter of concrete.
Gabe
Gabe,
Metric jokes aside, this is really important info, and I'm grateful you'd take the time to post it here.
If you're willing, I'd like to take this idea further. I'd like to dig in a little farther to these relationships between water, temperature, slump, cement content, strength, workability, and so on.
I do a lot of ICF construction, that having been said, I agree completely with what you said about ICF's not being the answer to all of the construction industry's problems.
I definitely occupy a niche in the marketplace, better-quality custom homes, typically environmentally responsible as possible, generally unusual designs. ICFs lend themselves particularly well to this.
So, of course I am interested in producing the very best house I can. As much as I like ICFs, there is no doubt plenty of room for error, and always room for improvement.
Adding water for workability, as you point out, is asking for trouble. Getting material that is too dry in ICF forms can of course be really bad, also. I've been using superplasticizer instead. Seems to take the mix from the range of slump 3 or 4 (inches <G>) to the 5 or 6 range long enough to get good placement and consolidation.
I've never checked into how SP affects final strength. Any thoughts?
Also, would you talk a little bit about "strength?"
I get the feeling we are all using the term differently in this discussion.
We have all these folks who are geting good results using different methods under different circumstances. It would help me if I understood how the criteria for good concrete changes from job to job and place to place. I don't think I do.
For example, here in seismic zone 2b it would be unthinkable (and illegal) to leave the rebar out.
So when we say strong, I always wonder "strong how?"
As for compressive strength,the worst concrete I've ever seen is about 10 times as strong as anything we need for single story residential.
So do we need to look at modulus of elasticity? Tensile? Moment connection? Overturn? Shear?
And what do we really need?
The ICF manufacturer's info is prety basic, and I have been thinking for quite some time that I probably could understand this material better than I do. Some of these lintel designs, especially.
So, given that I do use this stuff, and probably will continue for some time, what are your thoughts on doing the best possible job?
DRC
Here's a site that you may find interesting from concrete testing.
http://www.constest.com/html/body_concrete_faqs.html#ConcFQTop
Typically concrete mixes are over engineered for safety factors and loadings.
If you want to get the best bang for the buck, contact your local supplier and get a mix designed for your specific application. Concrete will cure differently inside insulated forms at different temperatures. You may need one mix for winter and another for summer conditions. Super P's have little adverse effect on concrete strenght however the alternative of adding water certainly does.
Strenght in concrete is open to interpretation as you pointed out. The most important point in residential construction to remember is that your base material plays a bigger role in the performance requirement of the concrete foundation.
A foundation that is founded on poor soil and backfilled with poor material too early without protection will fail regardless of the strenght used in the concrete and the steel specified.
At the other end of the spectrum, one that is founded on bed rock, not located in an earhtquake zone, in a moderate temperate area, backfilled with porous sand will do well without any of the additives or steel that we have to use.
Duty calls, chat later
Gabe
Thanks for that link. Good site.
DRC
another unfortunate problem with ICF's is that in the north they are NOT being mfr'd with Performguard... so they become a safe harbor for vermin..... in the south they are required to be poured only with borate treated EPS... but it hasn't worked it's way north yet.. when i inquired of several mfr's their first response was ...
what ?
the ones who were serious said they could have their product shipped from the southern plants, but the delivered cost would be almost double..
sounds like the " not quite ready for prime-time players " to me....Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike,
What say you to afterpour borate injection and copper flashing to separate from wood members?
Our biggest concern here is carpenter ants, occasional powderpost beetles..
Excellence is its own reward!
piffen , are you sure about the (lack of termites)..?... i always thought there were none in Rhogue Island either ,.. but boy was i wrong !...
in any case.. i will not use foam products unless the mfr. says they will not support vermin... as the Performguard franchises claim ...
as to "afterpour"... if the borates are included in the mix.. they will permeate teh product... an after-the-fact injection has got to be costly and less effective... but .. always ready to learn ...
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 10/19/2002 11:20:25 PM ET by Mike Smith
Just an idea for when it's what you're stuck with.
I know copper makes a good barrier.
No termites here
But
Climates change.
Greenland used to be green.
There were crocodiles in New England not that long ago.
Fire ants and killer bees are moving north again.
Who knows where the termite border will be ten years from now?.
Excellence is its own reward!