How Much Snow Is To Much On My Roof

The chart below courtesy of paul schimnowski p e gives some examples of snow loads.

How much snow is to much on my roof.

As everyone knows cold fluffy snow is very light while wet snow can be extremely heavy. For the twin cities metro area the roof snow load equals 35 pounds per square foot or 7 x 50. Roof collapse can happen to new and old buildings alike and can cause extensive damage to the building and contents. Most roof designs can handle snow loads of 20 40 lbs per square foot.

The roof deck collects the snow load and transfers the weight to the rafters. As everyone knows cold fluffy snow is very light. You have probably heard of or seen the difference between wet snow and fluffy snow. How much snow can my residential roof hold.

Low pitched and flat roofs are most susceptible to collapses. Most roofs are built to support heavy loads of snow without having any problems all winter long. How much snow is too much for my roof to support. But as the chart below shows packed snow with ice can.

Wet snow weighs considerably more than dry or fluffy snow because as you can probably guess water weighs more than air. For the twin cities metro area the roof snow load equals 35 pounds per square foot or 7 x 50. So how much snow does this equal. The residential code of ohio which applies to one and two family homes shows a map indicating the required snow load.

For any rafter the portion of the roof deck that transfers this load is the tributary area. 57 pounds a square foot. So you most likely will never have to worry about removing snow from your roof. These questions aren t quite so easy to answer because there are several variables.

We have some good news for you. How much snow a roof can hold depends on the type of snow roofline and material among other considerations. It calls for 20 psf throughout most of ohio and 25 psf along a north south strip in the eastern half of the state. Fluffy fresh snow can weigh as little as three pounds per square foot compared with 21 pounds for wet heavy snow according to fema.

So how much snow does this equal. One of the major determining factors for how much snow is too much for your roof is how heavy the snow fall is. The 20 psf load is equivalent to 14 inches of snow at the design.