Clients are often surprised when we tell them that we actually like to build homes over the winter. We've started new projects in every month of the year, and every season comes with its own challenges. Starting in the Fall or Winter is definitely possible and it doesn't have to add a whole lot of extra costs, but there are a few things you should watch for when the weather gets a bit colder.
1. If there is already frost in the ground, be sure you are excavating deep enough to get past the frost, because you want to avoid pouring your foundation on frozen soil. Soil moves significantly during the freeze/thaw process, so ideally you would pour your footings on the same day as it was excavated. However, if that is not possible, be sure to keep the virgin soil from freezing by using insulated tarps or heating if necessary.
2. When you are ready for backfill, be sure to use material that is not frozen. Frozen material is typically very clumpy and can cause localized pressure points on the fresh foundation before its had a chance to fully cure. Backfilling with frozen material is a bit like filling a glass with rocks. It creates gaps and voids which will lead to excessive settlement in the Spring which can cause other issues. (continued below)
Building a home in the winter is entirely achievable with the right knowledge.
3. Pouring concrete in cold weather can be the most critical part of a winter build. Cold weather will increase concrete set times, retard stiffening, and slow its strength gain; however it is interesting to note that concrete poured properly in cold weather can be superior to concrete poured in hot weather. If the concrete doesn't freeze and is cured properly, it can reach a higher ultimate strength, is more durable and less susceptible to thermal cracking.
Depending on the overnight lows and daytime highs, concrete suppliers will automatically add chemical accerants and air entraining agents to help the concrete cure properly in cold weather. Once the foundation is poured and placed, we drape the walls with insulated tarps as quickly as possible to trap the heat that is naturally generated by the chemical reaction of curing. In extreme temperatures, the entire foundation will be hoarded and heated for 48 hours.
4. Now that your foundation is in place, backfilled, and framing has begun, the goal should be to start heating the basement ground as soon as possible. This will allow for under slab plumbing, electrical, and prepping for the new concrete slab. A concrete slab should never be poured on frozen material.
5. All of these issues can involve the use of temporary heat on the job site. Depending on your location, there are several ways to heat your project.
220V Portable Construction Heaters - these are fantastic sources of heat if you have access to 220v electricity; however, they can be expensive to run long term depending on power prices in your area.
Portable Natural Gas Heaters - some municipalities will allow you to install the gas meter immediately after backfill, allowing you the opportunity to use natural gas a a temporary heat source for construction.
Propane Heaters - Propane is another good option if natural gas or electricity is not readily available. Obviously, you will be responsible for monitoring the fuel level on a regular basis.
Diesel Fuel Heaters - Similar to propane, these heaters work well on site, but require continual monitoring so they don't run out of fuel.
Regardless of the type of temporary heat you choose, safety is paramount. Ensure that there are no combustibles in the vicinity of the heat source, and if you are using one of the fuel burning options, proper ventilation is key.
Once the foundation is poured and your basement slab is in place, the rest of the process carries on in a fairly normal manner. Most trades are willing and able to work in colder weather if they have a place to warm up throughout the day and keep materials from freezing. One of the only other trades who may be drastically impacted by cold weather is the roofer. An icy, snowy roof is a dangerous place to be. Waiting for a break in the weather to ensure safety and productivity is completely acceptable.
Building in the Fall or Winter months is completely achievable. You may incur a few extra costs such as heater rentals, but it really doesn't have to be significant. Time delays can occur, but this can also happen in the Spring with rain and mud. We rarely discourage clients from starting a project in the cold weather, unless there are extreme conditions affecting the job site. Wondering if you can start your new home in a snowy climate? Give us a call, or contact a builder in your area for professional advice.
Until next time,
Richard Knappe
Construction Specialist