Our Roofs and Decks are Designed to Handle Snow, but How Much?
Press Release Snow Load 2-26-19
The recent storm systems have dropped a substantial amount of snow in the Greater Tahoe Area, including the Town of Truckee. Many residents have contacted the Building Division asking how much snow their roof or deck can handle before they need to shovel. Here are rules of thumb to calculate the anticipated snow depth for a roof or deck:
- Go to www.townoftruckee.com > Government > Building and Safety > Snow Load Design to obtain the ground snow load for your parcel
- Multiply the ground snow load by 0.7 to obtain the approximate roof snow load (this snow load is also used for raised decks above the anticipated ground snow load depth).
- Divide the ground or roof snow load by 25 pounds per cubic foot of snow density to obtain the anticipated snow depth.
The ground snow load for Truckee Town Hall is 179 pounds per square foot
Approximate roof snow load = 0.7 x 179 = 125 pounds per square foot
Anticipated snow depth for a ground level deck = 179 / 25 = 7.2 feet
Anticipated snow depth for the roof = 125 / 25 = 5 feet
- Doors or windows have become difficult to open
- Cracking in drywall
- Beam deflection (sagging)
- Walls or posts out of plumb
- Displaced deck beams or joists at connections (commonly due to dry rot)
If you notice any of these warning signs please consider contacting a snow removal company, and/or obtaining a professional opinion from a civil or structural engineer. If you decide to shovel, take appropriate precautions to avoid slipping and shedding snow hazards, and make sure someone knows where you are and can assist you if you become injured or stuck.
If you can safely do so, shovel the entire roof or deck rather than just one side or portion, as uneven snow removal can create an unbalanced load situation and increase loads on adjacent portions of the structure.