sand and cement question

[lovejoy]

The paving stones in my back garden need re-pointing, all the cement has eroded over the years, I was going to do it today but weather forecast says temperature will only be 2 degrees celsius.

Will cement set at that temp?

thanks

 

[^woody^]

Yes, as long as it does not freeze

 

[lovejoy]

Thanks woody

 

[r896neo]

The usual advice is temperatures of 3 deg and rising. Pointing on patios is particularly vunerable and with frosts overnight is a bad idea. Unless you cover with a layers of hessian.

Why risk it? Its a pain of a job and you don't want to do it twice.

 

[^woody^]

3° and rising is a general guide for winter time when sub-zero temperatures (ie falling) are expected. If the temperature stays above freezing then it will be OK, and rising temperatures are not a requirement.

The weather forecasts for minimum temps tend to apply for spots in the middle of nowhere, so if the OP is in an urban location, then temperatures will tend to be higher

But yes, always protect from frost

 

[tony1851]

Get a patio heater.

 

[r896neo]

If its even close to 2 degrees during the day its a pretty fair assumption it will be colder overnight.

 

[ConcreteDrBill]

Cement setting is a chemical reaction so it slows down at low temperatures. Whilst cement will set at 2C it will not gain much strength and will be very susceptible to frost attack (the water in the mortar freezes and expands, in a weak mortar this leads to cracking). You will need to protect the mortar from frost and keep it covered for a few days to enable it to gain sufficient strength to be frost resistant.

Always better to lay mortar (and concrete) on a rising thermometer

 

[noseall]

Always better to lay mortar (and concrete) on a rising thermometer

Won't that make a mess of the thermometer?

 

[ConcreteDrBill]

Hmmmmmmmmmmmmmm!!!