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.
Soffit follows roof pitch.
7 12 to 10 12 roof pitches increase the amount of ventilation by 20 percent.
A vaulted ceiling follows the roof pitch with finishing materials applied to the rafters.
Where roofs of unequal pitch join it requires careful layout to create equalwidth soffits with equal height fascias.
Another by product of this roof configuration is varying soffit heights and widths which require further design decisions.
They are generally made of two by four lumber and are used to form the pitch of a roof.
To maintain a consistant ridge height in these situations the roof pitch must be adjusted.
To ensure proper ventilation calculate the correct number of soffit vents for your home.
The top fascia to under soffit measurement is from top of fascia under roof sheeting to the bottom side of the soffit sheeting.
They come from each side of the roof and meet in the middle to form what looks like a v.
And in many of these cases the hip roof forms a large volumetric attic space to ventilate.
Figure 7 mechanical ventilation used with a hip roof.
Rakes are always miter joined at the ridge of your roof.
Rafter roof rafters are one of the most important parts of any type of roof.
Rake boards follow or parallel your roof pitch.
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.
There s no correct way to finish rake lower edges.
The most common parameter is to maintain an equal ridge height over building sections with differing spans.
One method is to use a powered attic vent with a humidistat thermostat located close to the ridge or top of the roof.
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.
Of course there should be intake vents to ensure a balanced system.
The second number run is always going to be 12.
The calculated soffit drop is the measurement from top of wall vertically down to the underside of soffit sheeting.
For projects involving vents with motors the calculation formula is different.
When a pitch value is shown it will appear as 2 12 which would indicate a nearly flat roof or 18 12 very steep.
11 12 roof pitch and higher increase the amount of ventilation by 30 percent.
That first number is what changes but stays within a range.
2 12 pitch or lower low slope or nearly flat.
In this article we stick to the basics which follows this logic.
This ceiling can make a porch feel larger add drama to the space and keep your porch cool in hotter climates.
