Any Masons or Bricklayers On Here?

[Kitchen]

My wife and I are in the process of redoing the landscaping in the front of our house and recently built a flemish bond brick retaining wall on the upper part of our garden.  We also redid our paver walk way.  Nether the existing wall nor the walkway was built correctly and we have a fair amount of dirt left over.  So, we are planning on building a raised brick garden bed in the lower part of our garden to match the new wall, which we wanted to do regardless if we had extra dirt or not.  

We poured the footing earlier this week and would like to start building the wall as soon as possible.  The land is graded, including the walkway, and the footing was poured level, which has left the upper part of the walkway's sand foundation exposed, so you can see why I want to get to this quickly.  

My concern is the overnight temperatures that are forecast for this weekend and how it will effect the mortar.  (I am using type S portland cement based mortar.)  Daytime temps are in the mid 50s F, but in the overnight it will be getting down to 36 on Sat and 33 on Sunday.  

Should I be concerned with these overnight lows?  

Thanks.  

[CaptainQuintero]

*Amateur DIY disclaimer*

  How thick is it and how big are the areas? It can't hurt to cover it over for a few days if you're going to get frost etc

  If you're worried about cracking, it's pretty much a matter of 'when, not if' with concrete, but it should be superficial if it's been mixed + poured well. If you're thinking of when can you build on it, it depends what sort of weight you're planning to put on it. A week is about enough for a drive way.

[Kitchen]

It is not the concrete I am worried about, but the mortar between the bricks not curing correctly due to the lower temperatures.  

I know that hydration stops below freezing and below 40 degree it can be slowed drastically.  Also, if the water content is above 6%, freezing will cause structural damage to the joints, which I don't want either.  All of the info I have found on this gives precautions for when the temps are below 40 when starting.  However, I have not been able to find anything written on what to do if the temps are in normal working range when starting but drop into the 30s overnight.  

I am just wondering if this is something to be concerned about?  

For the record, the wall itself will be a double wythe flemish bond and will reach a height of 2 to 4 levels, depending on the location.  Circumference is about 40 ft and there will be 12 to 14 weep holes installed.  

[nKostyan]

It will not be superfluous to cover at night with plastic wrap and on top of another geotextile a couple of layers or any other suitable warm insulation.

Cement mortar should gain at least 70-80% before it can be frozen without negative consequences

 

[Kitchen]

So something like R-19 insulation with plastic over top should work well?  

[nKostyan]

So something like R-19 insulation with plastic over top should work well?  

I don't know how flexible it is or how to connect it. The geotextile is connected by a stapler elementary.

[Phillys]

Used to lay brick in my early 20's, we layed brick in Quebec Canada from March to late November and sometime well into December. If got near freezing, we would tarp the scaffolding and use a propane heater to keep it around 55F during the night. You have about a 48h window before your mortar sets, you don't want it to freeze during that time, then another 5 days and it's mostly cured.

Tarps overnight are good, if it dips a bit below 40, in the best scenario, you would use an insulator blanket, about 1" thick with thick poly on top. It can be done, but are you in a real rush?  

[Kitchen]

Thanks Phillys.  I am not in a terrible rush, but the front of my house looks like hell.  I would like to get this done before the winter.  

[Phillys]

3 hours ago, Kitchen said:

Thanks Phillys.  I am not in a terrible rush, but the front of my house looks like hell.  I would like to get this done before the winter.  

Looking at the forecast in Philly, looks OK for the next 5 days, then it gets cold. If you have the insulation and poly, you *should* be good. Worst case scenario, your mortar won't be as strong and might become brittle with time...