(Should I/How can I) have concrete driveway repair and tuckpointing work done in cold weather?
November 14, 2010 7:15 AM   Subscribe

A contractor is planning to come out this week and replace a substantial portion of my driveway. It (was and) will be a concrete driveway. The same contractor ('s father) will also be doing a substantial amount of tuckpointing. I live in Cleveland and as you know this is mid-November. Should I be concerned about the cold/snow/rain affecting the durability of their work? What should I expect them to do to adapt to the weather? Should I just try to get them to wait until Spring?

First of all, this is a thing, right? Cold weather affects concrete? What about the tuckpointing? You can see that I'm really in above my head here.

It was unseasonably warm yesterday, but it will be cold and snowy/rainy this coming week. And of course, November/December are hard to predict but it's the beginning of Winter in a fairly northern area. There will be freezing nights and days. Snow. There may be a couple more warm spells, but generally it will be cold.

I gave him a (relatively small) deposit a month ago. The contract (if it even is such a thing) is very vague. No info about when they'll start and no details about exactly what we verbally agreed would be tuckpointed. Also, practically no technical details about how the driveway would be made. Suggestions regarding the social/legal aspects of handling this situation are also welcome.
posted by stuart_s to Home & Garden (9 answers total)
When my concrete driveway was laid (in a New Jersey summer, no less,) I was told I shouldn't drive on it for 3 weeks to a month, but if I had to, nothing heavier than a car after 2 weeks. Yes, cold weather slows the curing process as does rain. This seems like a bad idea, but I'm no expert.
posted by InsanePenguin at 7:29 AM on November 14, 2010

I'm not a mason by any stretch of the imagination, but I used to be a concrete finisher in Oklahoma. The weather isn't as cold there as in Ohio, I imagine, but here's what I know:

Colder weather, in my experience, is actually better for concrete. You don't have to use as much water in it to keep it plastic, because it isn't setting up as fast when the temperature is cooler. The lower the ratio of water to cement in the concrete, the stronger it will be. The slower set-up time is beneficial as well, because it gives there's more time for all the water to evaporate out. Once again, less water = good for the 'crete.

The only thing that I know of that you'd need to be careful about is the slab freezing before it cures. That can be disastrous from what I've heard- I've never experienced it myself. From what I know, the way to prevent this is with curing blankets placed over the slab when there's a chance of freezing. This holds in the heat that the cement produces as it cures (which can be substantial). I've also heard of hay being used. I would assume that any concrete contractor in Cleveland worth his salt would be prepared for this. But it wouldn't hurt to ask about it before they pour, especially if the forecast calls for very low temperatures.

On the tuck pointing, I really don't know. I would thin that the main concern, once again, is freezing. Cementitious materials (of which mortar is one, like concrete) generally behave in similar ways, but there can be differences depending on the mix. Concrete and mortar use different types of cement, for instance, and in a different ratio to the other ingredients if I'm not mistaken.

Good luck on your project!
posted by Shohn at 7:29 AM on November 14, 2010

Just as a point of interest, concrete cures best under water according to my former employers, civil engineers. There are also additives you can add to your concrete to make it set up faster/stronger (we used one for a fire station driveway - they could park a truck on that thing in 12 hours) or in colder weather.

Asking the contractor what he plans to do sounds like the best idea.

(I know nothing about driveways, sorry)
posted by WowLookStars at 7:44 AM on November 14, 2010

Great, sounds like my contractor had no idea what he was doing, haha.
posted by InsanePenguin at 7:51 AM on November 14, 2010

Your guy should be using air-entrained concrete and he'll need to keep it above 50 degrees for at least three days to cure it properly.* It can get colder than that and still be fine, but it'll take longer to cure. And if it freezes, well, then you're fucked.

*I have never worked with driveway concrete, so there may be additives that alter the curing time. This may be why he's willing to do the job now. I dunno.
posted by BitterOldPunk at 9:10 AM on November 14, 2010

You will have to ask your contractor what the plans are to deal with freezing weather. Cool weather is not a big issue, but if there is a chance of freezing or near freezing temperatures, then measures will need to be taken (but this isn't rocket science, concrete is poured in the cold all the time). If this contractor does concrete work all the time, they probably know how to deal with local weather conditions. If he has a reasonable-sounding plan (additives, blankets, etc), then you should be fine, but if he doesn't then I'd suggest finding someone who knows what they are doing.

The tuckpointing is a bit more of a concern because it will be harder to keep warm enough (as cement cures, it gives off heat, so covered large areas stay warm, but if you only have a little cement in a large area the heat produced may not be enough).
posted by ssg at 9:41 AM on November 14, 2010

Shaker Heights here, and we had chimney tuckpointing done as a condition of purchase back in February. No issues so far. Can't speak to the driveway though, since ours is a total shitshow.
posted by chesty_a_arthur at 1:17 PM on November 14, 2010

If your contractor works in Cleveland, he should be quite familiar with pouring concrete in cold weather. Cold weather is not a problem and in fact, the final strength of concrete is better under cool conditions. However you want to avoid freezing in the first 24 hours. Water in concrete doesn't freeze until around 27 degrees F, so even a little snow on the surface isn't harmful. Concrete produces heat while curing and it takes a while for cold to penetrate a slab, so even a few hours of freezing temperatures shouldn't cause any harm. After the first day or two, the concrete is strong enough to resist freezing. Just make sure the ground is not frozen before pouring.

If concerned about freezing, you can ask for air-entrained concrete. This produces microscopic bubbles in the concrete that provides space for any freezing water to expand without damaging the concrete. Air-entrainment is achieved by adding small amounts of chemicals that produce bubbles, much like adding baking soda to biscuits.

Also you can ask for extra cement in the mix, about 100 pounds extra per yard (going from 5 or 5 1/2 sack to 6 or 6 1/2 sack concrete). A sack is 96 pounds. This allows the concrete to more quickly achieve sufficient strength to resist the stress of freezing.

Finally, they should ask for a little less water in the mix, what is called a 4 inch slump. The slump test is just a definition for how much water is added to the mix. They don't actually need to do a slump test because they have already calibrated the mixtures at the concrete plant to produce the desired slump.

You should be fine if they pick a day that the temperature doesn't get below 30 degrees for more than a few hours at worst. Your contractor will be experienced enough to take care of all the concrete specifications above. They do this stuff for a living and know all about it.
posted by JackFlash at 1:40 PM on November 14, 2010

Response by poster: So, if all the necessary precautions are taken and the weather stays above freezing for the first couple days, then is the driveway's durability comparable to what it would have been in better weather? Or do we get something "satisfactory considering the conditions? "

The forecast is pretty scary. What's the timeline for a job like this? Is it a one day job? Or does it take a whole day (or more) to remove the old driveway? (It's a narrow driveway, but the garage is behind the house so it's not short. They're also replacing the wider section in front of the two care garage. I'd guess it's a total of 900 sq ft.) The low for Thursday is predicted to be 32 F... then the 30's for a couple days... then the 40's for a couple days... then a day in the 30's before a whole week in the 20's, mostly the low 20's.

"That can be disastrous" and "You're fucked?" Is this something that will be obvious immediately or is it something that will only become apparent in five years when the contractor can just say it's not his problem anymore?

Thanks, everyone.
posted by stuart_s at 9:39 AM on November 15, 2010

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