How Much Snow Can My Roof Handle?

Here’s all the typical Q&A you will want to know: Be prepared!

Q: How much SNOW can my roof handle?

A: During the worst snow storms many of us are left wondering just how much snow our roofs can handle. What many people don’t realize is that the critical factor is not about the depth of the snow, it’s about the weight. Why you ask…because wet snow is much heavier than dry snow and 6” of wet snow weighs about as much as 38” of fluffy snow and if the storm brings in rain after the storm you can bet that it will bring more strain on the roof.

Q: Why do I need to get the snow removed from my roof?

Heavy snow will place stress on your roof and put your home at risk for leaking and roof cave-ins. Unfortunately, freezing temperatures often cause ice dams when they mix with snow. Ice dams can’t form without snow and if you’re able to prevent them you are more likely to prevent your roof from leaking and damaging the inside of your home. Find out how to prevent ice dams.

Q: What can MY roof handle?

A: While your roof can be different than your neighbors every roof has a complex assembly of rafters and related structural trusses, deck and roofing material. Whether a roof can sustain a load without damage depends on:

• • Depth and density of the snow
  • Depth and spacing of the rafters and trusses (closer = stronger)
  • Surface slope and texture of the roof (ideal is smooth and steep so snow falls off)
  • Shape and location of the snow drift (a more sheltered area might result in an large uneven snow drift which might cause a roof to fail.  

Q: What types of roofs are more prone to snow overload?

A: Builders constructed older New England homes long before building codes existed, so these homes have less framing than building codes require today.

These types of roofs can be more prone….

• Shallow roofs near taller, steeper ones are especially vulnerable to snow sliding down.
• Wind exposes roof sections located in certain areas.
• Roofs with wide spacing of rafters.
• Homes (roofs) that underwent un-permitted renovations with improper removal of load-bearing walls.

Q: Is there an exact amount of snow I need to worry about?

A: There is not an exact amount of how much is too much, but know that you should look for signs of distress to gauge that answer for your home. Lift a few shovels of snow to identify its type, then determine whether it’s wet or dry.

Q: How Do I know there’s a problem? What are the roof distress signs of an overloaded roof?

A: Snow overload causes roofs to show the following signs of distress:

• Bent, bowed, or cracked rafters appear on roofs that are flat or slightly pitched.
• Do you hear any popping sounds?
• Do you have previous damage from heavy snows, fire, termites or rot?
• When doors on interior walls (leading to 2^nd floor bedrooms, closets and attics) begin to stick and you have trouble closing the doors (structure of the house will distort the door frame).
• Visible cracks in drywall or plaster around door frames

Q: I see these signs and the snow is excessive, now what?

A: Don’t reach for a ladder and a shovel. Safety first!

• • Call a professional to come and remove the snow and ice with a roof rake with an extension pole. A roofing professional will take care not to damage any flashing or shingles.
  • In addition, most home roofs aren’t readily accessible, making the job dangerous for most to handle handle. Unless you are Norm Abram from This Old House, call us at Coastal Windows & Exteriors to handle your roof raking as it’s the smartest and safest option.

When you do hire a roofing professional to rake the snow off your roof, make sure they are licensed and insured and note that the goal is not to remove all visible snow and ice, but to ease the load on your roof. Beware of roof snow removal companies that offer surprisingly low rates, as they are most likely uninsured and under-qualified. The last thing you want them doing is damaging your roof shingles.

At Coastal Windows & Exteriors we offer roof inspection in Massachusetts, New Hampshire and surrounding areas. Please call us today (978) 304-0495 if you need help.