Five best practices reasons for using roofing felt underlayment.
For roof slopes from 2 12 to 4 12.
On roof slopes of 2 12 to 4 12 the remainder of the roof shall be two layers of 15 felt applied in shingle fashion or 1 layer of ice dam protection.
Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter.
This will give you the rise over run or pitch.
If the rise is 6 inches for every 12 inches of run then the roof slope is 6 in 12 the slope can be expressed numerically as a ratio.
A handy roof slope estimator can help you determine if your roof slope is likely too low for shingles.
If this isn t practical then perform the same measurement on the underside of.
The combination of two numbers are used to display or show the roof pitch.
Roof pitch is a term describing how steep or flat your roof slope is.
Lapped nonsoldered seam metal roofs with applied lap sealant must have a minimum roof slope of 1 2 12 4 slope.
A pitch over 9 12 is considered a steep slope roof between 2 12 and 4 12 is considered a low slope roof and less than 2 12 is considered a flat roof.
So a roof with four inches of rise every 12 inches horizontally run would have a slope of 4 12 sometimes displayed as 4 12.
Simply put it s a shallow roof.
On 4 12 or greater slopes the balance of the roof shall be one layer of 15 felt.
A 2 12 roof slope means your roof has 2 inches of vertical drop for every 12 inches of horizontal distance.
The slope of a roof often referred to as the pitch is determined by rise over run the roof s vertical rise in inches for every twelve inches of horizontal length the run.
Roofs at the lower end of the range about 4 12 to 6 12 are relatively easy to walk and work on.
For example if you measure 4 inches the pitch of your roof is 4 12.
The table below shows common roof pitches and the equivalent grade degrees and radians for each.
The majority of north american residential roofs have historically been constructed with a slope between about 4 12 and 9 12.
That means the roof doesn t shed water as easily as steeper roofs which is why choosing the right type of roofing material is so important.
Standing seam roof systems must have a minimum roof slope of 1 4 12 2 slope.
Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof.
A roof that rises 4 inches for every 1 foot or 12 inches of run is said to have a 4 in 12 slope.
Most roof s have a pitch in the 4 12 to 9 12 range.