More than two feet of snow fell in some communities during the 2016 winter storm. Snow is a blessing and a curse for a home inspector. On the one hand I get the chance to look for active leaks, but on the other hand many defects are hidden and I can’t fully inspect certain areas. There is one major benefit to inspecting after a snowfall though, and that is the ability to see if a finished attic is properly insulated and vented.
Finished attics prevent a home inspector from seeing many things on the underside of the roof like proper rafter construction, electrical wiring, possible mold, and proper insulation amongst other things. So how can snow help a home inspector detect improper insulation and venting? Uneven snow melt.
Warm air rises, and if an attic is not insulated properly this warm air will leave your home and enter your attic. Since your attic is now warmer than it would be otherwise, and since your venting may not be sufficient enough, the snow on the roof begins to melt in an uneven symmetrical pattern. The rafter themselves supporting the roof are providing some level of insulation so the section of the roof over the rafter will melt slower.
Proper attic insulation and venting is essential to preventing heat loss and promoting an energy-efficient home.
Uneven snow melt on your roof is just one of the minor problems with insufficient ventilation and insulation. Ice dams forming is the major problem of this attic defect and the real cause for concern. Melted snow flows down the roof and towards the eaves where it can collect and refreeze. If it freezes it can cause damage to the shingles, the gutters, and the siding of your house. Have you seen those pretty icicles at the eaves of a roof? While pretty to look at, these icicles are dangerously sharp and a sure sign that ice damming could be happening to your home.
If you see any of the signs above—uneven snow melt, icicles forming at the eaves, and or major difference in temperatures in a finished attic--you should contact a qualified contractor to check the insulation in your attic and the venting.
Next time you take Sparky for a walk keep an eye on the neighbor's roof. You could save them some money and maybe earn yourself a nice hot chocolate.