Recommended roof slope in the north east (NY, NJ, MA etc) 1

[lboada]

Is there any recommended roof slope for regions with significant ice and snow loads? It a 2 to 12 a recommended roof slope? If so, where is such recommendation?

 

[boo1]

"You must check with your local building department to determine whether there are any regional restrictions on minimum roof pitch. However, assuming the structure is properly designed to handle expected snow loads, even flat roof designs may be permitted. Typically, a minimum of one-quarter inch per foot of slope is required to ensure that water drains from the roof. However, for both practical and aesthetic reasons, a roof pitch of 4 in 12 is more typical of the minimums we like to see. In snowy areas, even steeper pitches are recommended, such as 6 in 12 or greater, to encourage snow to fall off while minimizing accumulation on the roof."

Your roofing contractor can also help with details and design considerations

 

[SlideRuleEra]

Great advice from boo1. A roof pitch of 4 in 12 is considered the minimum where typical asphalt shingles can be used without taking additional steps to insure water does not get under the roofing. Slope on a metal roof can safely be much less.

Your question reminds me of growing up in 1950's South Carolina, were there is rarely any ice or snow. As kids we would marvel at the extra-steep roofs used on local "Pure Oil" service stations (now part of the Phillips 66 company). Apparently Pure Oil used one plan for their traditional stations, no matter where located in the USA. This photo of a former Pure Oil station, from the web, shows the benefit or the time tested way to minimize roof problems:

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[Archie264]

Love it! Makes sense...

 

[Ron]

Obviously, the more vertical, the better the drainage. Works for residential....rarely for commercial.

For most commercial roofs, very low slopes are still the norm. There was a time when "dead level" was an acceptable roof system....but that was when coal tar bitumen was the waterproofing medium of choice....no longer so. Newer and "improved" materials cannot withstand the dead level condition, thus the general code requirement for at least 1/4" per foot slope.

For structural design, as boo1 noted, it really doesn't make any difference....you can design for anything. In general, the higher the slope, the lower the cost of roofing....interestingly enough, the higher the slope, the lower the structural cost as well (with some exceptions!)

 

[boo1]

for Residential
6/12 and under you can walk on them
7/12-9/12 premium charge for labor
10/12 up double charge for labor

Materials required increase with slope increase

Again talk to your building dept and a roofer

 

[racookpe1978]

And in that photo above, notice the 7 foot high pile of snow between the two buildings.

Not often found below the Mason-Dixon line. Boston got hammered with multi-foot blizzards this past winter; and those snow loads collapsed several building roofs made with low slopes from "standard plans". The NY-NJ area could get the same next winter.

 

[medeek]

For areas with lots of snow I would suggest metal roofing with as steep of pitch as possible. You'll never have to worry about shoveling snow off of your roof and infiltration of water due to ice dams will be a non-factor.

A confused student is a good student.
Nathaniel P. Wilkerson, PE

http://www.medeek.com