Urgent: pouring concrete in this weather

gunnerfitzy

Hi all,

As you are probably aware of by now from my previous posts i'm renovating a cottage in East Cork. UFH going down tomorrow. Concrete screed due to be poured tuesday.

I am concered about pouring the screed while the weather is a cold as it is. Much of my research on the internet tends to advise against pouring during freezing conditions.

My builder and engineer are leaning towards it being okay but I would appreciate any advise from experienced boardies before a costly mistake is made on Tuesday.

Thanks

FesterBeatty

Are you talking about pouring concrete indoors (i.e in a sealed building?)? To pour concrete you need 3 degrees and rising - your engineer is aware of that..

Quite simple, leave a thermometer in the area where you intend to pour, check the lowest temperature (overnight) and if its above 3 (which it might be if you're indoors??) then pour away, however you need to maintain this temp for at least 24 hours, so additional frost protection blankets may be required.

If the temp is below 3 (even internally at night) OR if pouring outdoors (i.e your buildings not fully sealed) then dont do it. The water molecules at the surface of the mixture will begin to freeze, and therefore expand and naturally lead to cracking...which obviously you dont want! I'm a structural engineer myself, currently responsible for a number of jobs around the country - not one of them is pouring in this weather..

gunnerfitzy

FesterBeatty wrote: »

Are you talking about pouring concrete indoors (i.e in a sealed building?)? To pour concrete you need 3 degrees and rising - your engineer is aware of that..

Quite simple, leave a thermometer in the area where you intend to pour, check the lowest temperature (overnight) and if its above 3 (which it might be if you're indoors??) then pour away, however you need to maintain this temp for at least 24 hours, so additional frost protection blankets may be required.

If the temp is below 3 (even internally at night) OR if pouring outdoors (i.e your buildings not fully sealed) then dont do it. The water molecules at the surface of the mixture will begin to freeze, and therefore expand and naturally lead to cracking...which obviously you dont want! I'm a structural engineer myself, currently responsible for a number of jobs around the country - not one of them is pouring in this weather..

Thanks for the advice. The majority is in a building but it is not sealed (no front door, windows broken). There is a small porch also. I will put it off until temps pick up.

Cheers again

gunnerfitzy

Quick follow up: does the temperature need to be above 3 deg for only 24 hours? Or is longer advisable?

I would like to try and get it poured during the 'thaw' that is due to arrive after xmas day.

Cheers

heinbloed

Contact a civil engineer. Concrete can be poured in freezing conditions as well, but this has to be done by the books. Not a cowboy job, everything has to be prepared.
The compacted ground/rubble/drainage layer should NOT be frozen when pouring, an uneven settling (during the pouring !) because of melting ice pockets would be the result, cracks ect. ...

kboc

risky business at this time of year.

Make sure all stake holders are aware of their responsibilty and who will pay for what if it fails. I may sound silly, but possible asked them to sign something stating this or tell them you are not paying until you are hapy concrete has cured prpoperly.

unfortunately i am speaking a similar experince with concrete. Which is now hugely expensive to fix

Remember this is your house, not the flooring contractors/concrete companies or engineers. The first 2 boys are looking for money before christmas probably.

Good luck

gunnerfitzy

Thanks again for the replies.

I decided it is certainly not worth the risk and postponed the pouring. It will probably be the new year before it will be done but it is certainly worth the slight delay to get it right!

robd

gunnerfitzy wrote: »

Thanks again for the replies.

I decided it is certainly not worth the risk and postponed the pouring. It will probably be the new year before it will be done but it is certainly worth the slight delay to get it right!

Good call.

Was doing a very small project and waited myself to pour foundation slap and lay blocks, when we had a break in cold snap. My research indicated loads of methods of doing this, but all in regions which would experience conditions like this as common place.

Quite simply we don't have the equipment (concrete blankets, heated concrete trucks) or experience to be laying concrete in Ireland in this weather.

FesterBeatty

It can be done of course, but will be highly uneconomical if you're only pouring a single slab. You should also be aware that you need 5 degrees and rising for most brickwork/blockwork mortars. Similar restrictions apply to tarmac etc.

Best best - Hold off until the new year.

gunnerfitzy

Thanks again for all the advice guys.

brendankelly

My view is that all building work should stop for the winter. I do lime plastering and I watch the weather from October. Once it goes below 5 degrees I stop until I see double figures in spring. The plasterers are responsible for the job until it is painted/whitewashed and this should not be done until the plaster is dry (about 6 months). Once bitten twice shy as they say.

SC024

brendankelly wrote: »

My view is that all building work should stop for the winter. I do lime plastering and I watch the weather from October. Once it goes below 5 degrees I stop until I see double figures in spring. The plasterers are responsible for the job until it is painted/whitewashed and this should not be done until the plaster is dry (about 6 months). Once bitten twice shy as they say.

Must be great money in that game

gunnerfitzy

Again, thanks to all for their input.

On inspecting the site over the weekend I noticed one thing that has given me some concern.

As part of the renovation the existing floor was dug out to allow a new sub floor to be put down, followed by the radon barrier, then the insulation and the UFH. This is the stage it is at now until the new year when hopefully temperature will be suitable for the concrete to be poured.

My concern is that the insulation is not level throughout the building. This is prevalent especially in the extension where there is a dip of maybe 1.5 inches between sheets of insulation.

Is there any need to be concerned at this?

galwaytt

brendankelly wrote: »

My view is that all building work should stop for the winter.

LOL, do you think people don't give out enough to us in construction already, or what ?? You want, what, 12month's pay for.......9 month's work ? Good luck with that...........

And of course, with dry methods of construction, there's absolutely no need to stop building. We worked right up to 23rd Dec and got a building up in the preceeding 10days - snow and all.

gunnerfitzy wrote: »

On inspecting the site over the weekend I noticed one thing that has given me some concern........My concern is that the insulation is not level throughout the building. This is prevalent especially in the extension where there is a dip of maybe 1.5 inches between sheets of insulation.

Is there any need to be concerned at this?

So long as the insulation is otherwise well-laid (staggered layers and joints) intact, and the thinnest part of the screed sufficiently thick, then it's not a major issue. Ideally, it should be level, but you are where you are, as they say........