Wisconsin has not adopted the international residential code irc and utilizes its own uniform dwelling code udc for all residential structures.
Minimum roof pitch wisconsin.
Sps 321 27 note note.
With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 20 0 for slate roofs.
Minimum roof pitch the minimum pitch for a roof is 1 4 12 which translates to 1 4 inch rise to 12 inches of run.
So you would need to pick the right option as most regular standing seam metal roofs will require a roof pitch of 2 12 or even 3 12 at a minimum.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
Where the rafter spacing is greater than 24 inches on center roof boards shall be tongue and groove at least 1 5 inches thick.
You could also opt for a pvc flat roofing membrane.
However roof pitch is technically measured and defined differently and will not be discussed here.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
A pvc roof is a lot more durable and longer lasting that a conventional epdm rubber roofing system.
Where the rafter spacing is 24 inches on center or less roof boards may be used that have a minimum thickness of 5 8 inch for solid sheathing and 3 4 inch for spaced sheathing.
However you can only use this pitch with built up roofing or specialized.
Note that roof pitch is sometimes used in parallel with roof slope.
Use our wisconsin roof snow loads map to easily determine the roof design snow load wisconsin administrative code.
Anything above that will require you to put out higher cost because they are already considered as higher pitch.
But since there is still a wide variety of slate roofing systems there are occasions when the minimum pitch can go down to as low as 15 0 depending on the uniqueness of the roof.
Provisions shall be taken to absorb the horizontal thrust produced by a sloping roof through the use of wall ties ceiling joists beams at the ridge or at the wall or a system designed through structural analysis.
A roof pitch of 7 in 12 is equal to 30.
Sps 321 27 2 2 lateral restraint of walls.
The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7.
If a roof slope rises say 4 inches when measured 12 inches along the bottom of a horizontal roof truss the roof slope is said to be 4 12.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
The values given here.
Sps 321 subchapter 2 for any location in the state of wisconsin.
I e 4 inches of rise per 12 inches one foot of run.
