Working through winter can be almost unbearable, but it doesn’t have to be. We reached out to contractors who have experience with cold weather construction for their input. One company is from the Northeast and the other from the Midwest, so they’ve experienced their fair share of winters and have a wealth of knowledge on the subject.
Cold Weather Procedures
Austin Norberg, Project Manager – Seedorff Masonry, Inc.: “The requirements for heating masonry materials and covering completed masonry can be found in the ACI 530 code. Items to consider from the code are the temperatures that mixing water needs to be kept at as it relates to exterior temperatures and requirements for covering completed walls at the end of the day or constructing temporary enclosures to maintain temperatures above freezing. It is a good refresher to review the code prior to the temperature changes to make sure the work will be in compliance.“
Paul Cantarella Jr., President of Cantarella & Son, Inc.: “The two biggest procedures are keeping the mixing area/materials warm, and keeping the work area where units are being laid heated. Hands down these are the two most important procedures to keep a job flowing in the winter.”
Cold Weather Construction vs. Warm Weather Construction
A.N.: “As cold weather starts to creep in additional steps need to be taken to ensure a quality final product. When temperatures are forecasted to below 40˚F, masonry units need to be kept above 20˚F, and mortars and grouts need to be heated to between 40 and 120˚F.”
P.C.: “There are many differences in the installation of block during winter compared to summer. It’s important to watch the joint’s stiffness and making sure to hit them at the correct time. As hot air always rises you will have different temperature, which effect the setup of the masonry joint. Towards the bottom of the wall it’s colder so you have more time until you need to install the joint. As work progresses up with the heaters blowing hot air it can dry the joints out quicker, which means you need to joint sooner. The masons have to battle the same thing. As they start the day down low they will need an extra layer of clothes, which can slow you down. As the scaffold goes up, the masons start to get hot and have to strip off a layer.
Throughout the day little things this can add up when you have 20 masons on a job. Also, if you have colored mortar on a project it becomes even more important to keep a consistent temperature so all the mortar dries at the same rate producing the same color. This is definitely one of the hardest tasks you will have! In the same breath it’s almost impossible to completely control because you will never have the same temperature in all the different areas and heights (heat rises), you are working at. Kind of a double-edged sword!!!”
A.N.: “During the winter months the conditions on the jobsite change and the crews need to take additional precautions to stay safe. Frozen ground can create additional tripping hazards, ice and snow create instances for falls and spills, and snow can cover hazards that are only found once it’s too late. Temporary shelters can leave puddles that quickly freeze once removed. The crews also need to be aware of the colder temperatures and take steps to keep warm and exposed skin covered to prevent frostbite. Another safety issue to review is bracing of scaffolding once it is enclosed. This creates a large surface area to catch wind and can push and pull the scaffolding out of place.”
P.C.:”Safety is a major factor in the winter for masonry construction. The first precaution is making sure your crew has the correct Personal Protection Equipment and clothing to do their job safely (Hard hat liner, warmer gloves, and jackets). The mixing shanty is another area where safety needs to be spot on. We usually install a corrugated pipe under the sand. At one end of the pipe we put a torch heater connected to propane in one end and then we locate our metal water barrels at the other end so the heat flowing through the pipe will keep the water barrels warm.
Having a torch with a flame go all night means lots of precautions and extra effort to build the mixing shanty to hold up to the weight of snow and the wind. We install carbon dioxide detectors as well as thermometer in our mixing shanties and on the scaffold where the crews are working. Also, just because it’s winter doesn’t mean you can stop having water available for the crew. Your body temperature can rise as you get closer to the top of the scaffold, increasing the risk of overheating. With safety rules getting tighter and tighter we are always trying to find new ways to heat the mixing area without compromising safety. There is some newer equipment starting to come out to help combat the cold, like electric water heaters and sand heaters.
The biggest safety factor is keeping the scaffold safe. By installing flame retardant poly it creates a big sail!! Scaffold needs to be tied off at smaller intervals as well as to concrete cubes. Also, the jobsite foremen need to know when to get the crew off the scaffold in case of high winds. We had a wall and scaffold go over in the winter years back. The scaffold was tied to concrete cubes and even a D10 dozer. It dragged them all. Unless you have had something like this happen you will never know the feeling you get in your gut (and grey hair). Having that happen to us made us more diligent with tying the scaffold off at smaller increments. I have had many sleepless nights (now I know what my father was talking about) because of being worried about the wind and scaffold being up. Also when the temperature really goes down you have to allow time for any of your laborers that are stuck out in the element time to warm up so as to not get hypothermia. Lighting can also become a factor. It is usually darker in the morning in the winter. Lights are installed in our mixing shanty so they can see clearly. All of our forklifts have extra lights (front and back) for this time of the year.
The same goes for the laborers getting the work area ready for the day light might have to be used for the first hour if you are out working on scaffolds at exterior of building. Additionally any propane tanks must be stored properly with correct safety signage. Safety harnesses should also be stored properly and not left out in the weather. I believe in stretch and flex in the mornings before starting your work day and I feel it is even more important in the winter to get you blood moving!!”
Considerations for Cold Weather Construction
A.N.: “Inspectors will also need to be aware of the changing conditions. Mortar and grout samples need to be stored in appropriate locations to closely resemble the work area. Samples stored at the base of a shelter may not cure out the same as the work being completed 20’-30’ above if measures aren’t taken to keep similar temperature. Inconsistent test reports can lead to additional testing or rework to confirm the masonry meets the design requirements.”
P.C.: “You will definitely need at least one to two extra laborers onsite, changing propane bottles, keeping ahead of the crew getting the scaffold enclosed, and fixing any holes or rips in poly on the scaffolds and mixing shanty. After snowstorms or even small amounts of snow, you have to clean all work ares including rooftops of the poly on the scaffold. Ice areas will need to be sanded. Depending on the foot traffic it might need to be done two times a day. Even little things like getting mason sand delivered can become more of a project. The laborer will have to open up your mixing shanty to dump the sand. We usually try to go with a pre-blended mortar in silos during the winter to avoid this hassle.
Block piles need to be uncovered so they can be delivered to the scaffold and also new block arriving has to be covered until it is used. Another factor is getting your water. Be sure you pick up the water hose and store it in a warm spot for the night or drain it. There’s nothing worst than showing up to a frozen hose and five masons waiting for their mortar. Another item to think about we have been coming across since we started going to cordless tools is that you need to store them in a warm area otherwise the cold zaps the life out of the battery. A good key factor is getting the base built before cold weather, with heat always wanting to rise in a tent it is very hard to keep the first 4’ warm when it is very cold out. It may seem like a waste of time to build just the first 4’ to 6 ‘ and keep moving but once the cold temperatures hit you will be thankful that you did. My father was always big on this one, it took some time for me to learn that he was correct and it is well worth the extra time and loss of production to do it.
We have installed concrete blankets at the base (sewn in with tie wire) to try and keep the heat at the base. With the winter months, we have the masons start an hour later than normal. You wouldn’t believe how much the temperature can go up in that 1 hour with sun shining. Loading materials to work areas is another task that adds time, openings for loading material have to be manually opened and closed by the laborer to help keep the heat in the tented area. Mortar tubs should be kept warm overnight so you are not sending the mortar out in a frozen tub, which will affect the workability of the mortar. Extra time may be needed for machines to warm up before being used. Any equipment with glow plugs will need to be plugged in nightly. If the CM/GC will not allow propane torch to be on all night in your mixing shanty you might have to have a labor start early every day to get the heat going. If the job is far from our shop we will have a laborer that lives locally start early.”
First-Hand Experience with Winter Construction
P.C.: “We have always worked winters up here in the Northeast. It’s not easy to do, but it can be done, we have definitely adapted to working in the winter. We have done it all, from new work to restoration using conventional scaffold and Hydro Mobile equipment. I still remember when they use to add dish soap to the water barrels! One time my uncle lit leftover mixing bags at the base of the wall because the lower work froze. Thank God the tent didn’t catch on fire. I’m sure glad we don’t work like that anymore. You will also need to start using #2 Diesel so it won’t get in the forklifts.
Advice For Contractors Working in Cold Weather
A.N.: “To keep projects on schedule, continuing masonry through the colder months is critical. Keeping a clean and organized jobsite is always a must but this is highlighted during the winter months. Planning for these changes will keep safe working conditions for the crew and allow the schedule to progress as efficiently as possible.”
P.C.: “Relax and take a deep breath. The winters here in New England can get rough. There will probably be days that all you are doing is removing snow and ice, taking two steps back for every step forward. With a little planning you can save yourself some major headaches. Staying on top of the major items that need to be done day-to-day in winter months will help keep the crew productive. Things definitely take a little longer so make sure you cover for the extra work in your bid. We also try to get bigger propane tanks onsite so we don’t have to change the small bottles out everyday. With proper signage and concrete barriers around the tank it is a major timesaver.
Keep track of your propane use so that you can get it dialed in for bidding future job that will go through the winter. I learned a long time ago before winter hits to make sure all your materials that are on the ground are marked or put away, otherwise you will have a blast digging up the snow trying to find you rebar or durowall pile on the job. Just hoping that snow didn’t turn into ice making it even that much harder to dig out! It is definitely harder to do masonry in cold weather, but it can be done and money can still be made as long as you cover your bases. Safety always!”