Snow Insulation Roof

A properly insulated home doesn t show bare patches of melted snow on the roof.

Snow insulation roof.

Many homeowners report that their homes feel warmer after a good snow as long as there s enough insulation in the attic floor to keep that heat inside and the snow on the roof. Rigid insulation layers exterior to existing roof sheathing must provide sufficient thermal insulation r value to control condensation risk see climate specific guidance. But on average snow has an r value of 1 per inch about the same as wood. Of course that amount of snow on a flat roof that s not built for it is going to cause all kinds of other headaches.

And more importantly where should you store all of it. Snow is an insulator. Its r value varies depending on moisture content and density of the snow granules. In fact having a reasonable depth layer of snow on a roof is a good thing as long as the roof is designed to handle the weight.

Without the insulation properties of snow the inuit could never have survived in the harsh arctic wilderness. That cold air vent space disallows help from the snow it would seem. Where you really see the amazing insulation properties of snow in action is in the igloo. Install roofing underlayment flashing and cladding as per best practices.

According to one anecdotal source a snowfall that measures about 0 07 inches in density or seven percent water volume has about the same insulation value as a standard batt of fiberglass insulation with an r value of 18. You have insulation layer snow cold air space vent then the insulated roof deck. Nailbase must be vented in high snow load areas. It also provides an additional level of insulation and protects the roofing material from sun exposure which is your roof s worst enemy.

Twelve inches of snow have roughly the same insulating value as a 2x4 wall filled with fiberglass insulation. If you re shoveling a tad too much you can damage the roofing tiles. Additionally insulation serves as a way to enhance sound proofing on the uppermost envelop of your house. Snow accumulating in decent amounts on your roof without melting in certain unusual spots is a testimony that your attic is doing its job meaning there s no heat loss through the roof due to poor insulation.

In essence creating a vented unvented hybrid roof assembly. Install nailbase for cladding. Insulating in and around your roof attic space also prevents long term damage from moisture build up or ice damming which results from the warm air trying to escape through the apex of the roof but instead heating up the snow. It does help with ice dams though.

A house that has a bare roof when all the others in the area are covered in snow or has excessive ice formation is a sure sign of poor insulation and inadequate. Who would have the energy to spend each morning meticulously shoveling the snow off the roof.