Exterior Insulation and Finish Systems (EIFS, or “synthetic stucco”) have seasonal application limitations – that is, they can not be applied when the ambient air temperature drops below 5 degrees Celsius… within 24 hours after any coating is applied. The ambient air temperature would be the temperature outside, with factors such as the sun or wind figured in. For example, it could be below 5 degrees Celsius when the actual temperature is 10 degree and a wind chill is factored in. The reasoning behind it is that the EIFS components (weather barrier, styrofoam adhesive, base coat and finish coat) contains water. When the temperature drops below 5 degree Celsius, the evaporation slows to a point that the materials will cure too slowly. This can result in efflorescence (a white powder being drawn out of the material) in the basecoat or uneven texture/colour in the finish coat because it has cured at different rates.
Then there’s the risk of the temperature dropping below zero degree Celsius, causing problems like finish coat delamination (peeling) and styrofoam adhesive failure (the wall my start to crack and fall off in sections). As the water in the products freezes it expands, creating larger spaces in the coatings that weakens it. These conditions apply not only to the application of the materials, but their preparation (mixing) and storage as well. It is always recommended to provided a heated room or area somewhere such as the basement to store the materials, off the ground.
How To Proceed With Winter Work
Despite the risks, there is a way to do stucco during the winter months. This is done by use of an enclosure and a source of heat. The enclosure is made by using large tarps to cover the scaffold up to your wall, usually building it up with 2x4s. While never air tight, and certainly not energy efficient, it does trap heat from salamanders (heaters) enough so that they can countinue working. Regardless of how well the tarping is set up, caution needs to be exercised. If the weather drops to negative 30 degrees or below, the heat provided by the salamander may not be enough to keep the whole wall warm. Brutal winter winds are notorious for ripping tarp off, and even a small opening in the enclosure can mean big losses of heat.
Heat is provided by way of a “salamander” and propane tank. The salamanders burn propane and direct it in a certain direction – usually at an angle the base of the wall. This helps to cover the most possible surface area, as heat rises. It is also important that the wall is heated to the proper temperature (5 degrees Celsius) prior to commencing work each day. While the salamanders themselves are inexpensive to rent, you will typically go through a 100-lb tank every 14-15 hours. This means that a new tank should be hooked up at the end of every shift, to last through the night. Current rates (I just checked this week) are about $53 per 100-lb tank. When you figure you need about 4 days on a 600-1000 square foot wall, you’re looking at roughly $400 in additional heating costs per wall.
A license is required to operate salamanders, and most rental places won’t even let you rent one without presenting your license. Licenses cost about $120, and I usually recommend that one of the home owners get licensed so that they are able to add a new tank themselves if required. It adds to the comfort level knowing how to work with the heaters, and being able to ensure the heaters are being handled properly by the contractors.
Many opt not to do it during the winter because of the extra costs, but there are ways of reducing it. If you find a particular contractor who is not doing any work during the winter, they may be willing to reduce their wages for the sake of keeping busy. You don’t want to negotiate a contractor too low, because just like everyone else in this world, if they’re being paid half as much to do work they may feel inclined to not deliver the best quality they are capable of. The contractors also need to take more time to set up tarping in addition to scaffolding, which will be more uncomfortable and dangerous during the winter.
Is It Worth It?
All things considered, you’re usually looking at between $1,000-$2,000 in additional costs for having home’s stucco done during the winter, depending on the size of the project. The contractor may be willing to foot some of this cost to keep busy, but it needs to be worked out on a per-project basis. Obviously, less heating is required during the early winter (just after fall) and late winter (just before spring) as the weather is not as cold as the middle of it. The benefits of doing it early winter is that once complete, you benefit from the additional insulation all winter, saving as much as $500 on your heating bills. You are also keeping skilled tradesmen employed, which I guarantee you they will be thankful for – assuming you don’t negotiate them too low. It’s worth discussing with your selected contractor, and if either you or them feel it wouldn’t be beneficial, there are no obligations to go through with it until the spring.