Blog

Autumn Construction

By Eric R. Kizak, P.E.

As autumn takes over New England our thoughts often turn to apple picking, fall foliage, mild days and cool nights.  For those of us in the construction industry those cool nights can instill a bit of panic.  Thoughts such as, “Will the project be completed before it gets cold?  How quickly am I losing daylight?  How does the temperature effect cure times?” start popping into our heads.  Naturally, pressures develop to just get the job done!

However, as the design professional, it is your job to bring these issues to the forefront.  At this time of year it is prudent and often necessary for the Owners, Designers, and Contractors all to take a brief pause.  The pause will not affect the CURRENT construction activities, but is intended to PREPARE for the upcoming difficulties associated with working in cold weather.  The following is a brief check list of construction activities that are temperature sensitive.  Considerations should be made for each. 

Material

Temperature Threshold

 

Concrete

40 °F

When the average daily temperature is less than 40°F concrete work shall be performed in accordance with ACI 306.  In summary, concrete shall be derived with a temp of at least 60°F and maintained above 50°F until cured.  Insulating blankets, direct application of heat or both may be necessary.
Masonry

40 °F

Masonry should not be laid unless the temperature is 40°F and rising and will remain so until the mortar is set.  If there is insufficient cure time insulating blankets, direct application of heat or both may be necessary.   Refer to ACI530.1/ASCE6/TMS 602 for additional information.
Steel

 

Temperature effects only need to be considered in very large spans (bridges) or sensitive structures (labs, research facilities, etc.). 
Waterproofing and coatings

40 °F

To comply with today’s VOC regulations most waterproofing and coatings are water based and therefore susceptible to freezing.  Most of these products will not yield desirable results if allowed to freeze before cured.  Additionally, as the temperature drops they require longer cure times.  In general, the temperature of the surface the material (very important) is applied on and the air temperature must be 40 °F and rising.  However, the manufacture of EACH product should be contacted for the particular requirements of that material.  We suggest a meeting at the site.

In summary, construction may continue in all weather IF appropriate cold weather preparations are made.  So take the time to pause and prepare now so that you can enjoy the apple harvest and the falling leaves with everyone else.