Soffit Follows Roof Pitch

The most common parameter is to maintain an equal ridge height over building sections with differing spans.

Soffit follows roof pitch. One method is to use a powered attic vent with a humidistat thermostat located close to the ridge or top of the roof. For projects involving vents with motors the calculation formula is different. A vaulted ceiling follows the roof pitch with finishing materials applied to the rafters. Figure 7 mechanical ventilation used with a hip roof.

Here s a rule of thumb to follow. You measure this as a rise and run equation such as 6 12 where the rake angle rises six units in 12 units of run. They are generally made of two by four lumber and are used to form the pitch of a roof. To ensure proper ventilation calculate the correct number of soffit vents for your home.

Rafter roof rafters are one of the most important parts of any type of roof. Rake boards follow or parallel your roof pitch. The second number run is always going to be 12. Drawing a superimposes the common rafters for the two roof pitches and illustrates the problem that occurs when roof layout starts at the outside edge of the exterior walls.

Rakes are always miter joined at the ridge of your roof. 7 12 to 10 12 roof pitches increase the amount of ventilation by 20 percent. 2 12 pitch or lower low slope or nearly flat. Of course there should be intake vents to ensure a balanced system.

They come from each side of the roof and meet in the middle to form what looks like a v. That first number is what changes but stays within a range. Where roofs of unequal pitch join it requires careful layout to create equalwidth soffits with equal height fascias. 11 12 roof pitch and higher increase the amount of ventilation by 30 percent.

The wall top to rafter bottom measurement is from top of wall vertically down to a point level with the bottom outside edge of the rafter not including fascia. For example six inches up for every 12 inches across. When a pitch value is shown it will appear as 2 12 which would indicate a nearly flat roof or 18 12 very steep. There s no correct way to finish rake lower edges.

This ceiling can make a porch feel larger add drama to the space and keep your porch cool in hotter climates. And in many of these cases the hip roof forms a large volumetric attic space to ventilate. The calculated soffit drop is the measurement from top of wall vertically down to the underside of soffit sheeting. Another by product of this roof configuration is varying soffit heights and widths which require further design decisions.

Up to 6 12 roof pitch use the standard formula as explained in this article.