Another by product of this roof configuration is varying soffit heights and widths which require further design decisions.
Soffit follows roof pitch.
There s no correct way to finish rake lower edges.
Figure 7 mechanical ventilation used with a hip roof.
To maintain a consistant ridge height in these situations the roof pitch must be adjusted.
7 12 to 10 12 roof pitches increase the amount of ventilation by 20 percent.
They are generally made of two by four lumber and are used to form the pitch of a 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.
Rakes are always miter joined at the ridge of your roof.
Rake boards follow or parallel your roof pitch.
2 12 pitch or lower low slope or nearly flat.
For example six inches up for every 12 inches across.
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.
One method is to use a powered attic vent with a humidistat thermostat located close to the ridge or top of the roof.
The second number run is always going to be 12.
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.
This ceiling can make a porch feel larger add drama to the space and keep your porch cool in hotter climates.
Here s a rule of thumb to follow.
A vaulted ceiling follows the roof pitch with finishing materials applied to the rafters.
The top fascia to under soffit measurement is from top of fascia under roof sheeting to the bottom side of the soffit sheeting.
When a pitch value is shown it will appear as 2 12 which would indicate a nearly flat roof or 18 12 very steep.
In this article we stick to the basics which follows this logic.
Where roofs of unequal pitch join it requires careful layout to create equalwidth soffits with equal height fascias.
And in many of these cases the hip roof forms a large volumetric attic space to ventilate.
For projects involving vents with motors the calculation formula is different.
Of course there should be intake vents to ensure a balanced system.
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.
That first number is what changes but stays within a range.
The most common parameter is to maintain an equal ridge height over building sections with differing spans.
Up to 6 12 roof pitch use the standard formula as explained in this article.
