Roof pitch
The roof slope refers to the slope or steepness of a roof surface. It is usually given as an angle in degrees, occasionally, in percent, rarely as a ratio. Depending on the roof pitch is referred to as a roofing flat roof, flat or pitched roof pitched roof. In development plans can be found next to the stipulations prescribed roof shape often those to the roof slope.
Calculation
The roof pitch is derived from the roof height ( = vertical distance from the ridge to the eaves ) and a standard size to the ridge ( = horizontal distance from the ridge to the eaves ). The angle of inclination is very easy to calculate using the arctangent:
- Arctan ( roof height / standard size to First ) = angle of the roof pitch in degrees ( On the calculator, the arc tangent function is usually as shown).
When converting from degrees to percent following formulas help it should be noted that one understands an inclination angle of 45 degrees with a 100% slope:
- Of grade in percent:
- From percent to degrees:
Constructional aspects
The roof pitch has an influence on the type of roofing, as some systems are only suitable for a defined range of tilt.
The lower the roof pitch, the greater is the danger that driving rain or blowing snow comes under the roof covering and the roof damaged. For this reason, the roof pitch of buildings with snowfall greater than in warm countries in cold countries. But the choice of roofing material will affect the driving rain. Tiles, for example, protect the roof from rain damage, as the precipitates are so directed by the higher-lying, covering roof tiles on the underlying that the water can not penetrate into the substructure. Similarly, at low inclinations of the self-cleaning effect of the roofing is at risk and the risk of thatch is increased. Even with flat roofs ( ≤ 5 °) the roof slope should be at least 3 °, so that rain water can drain off and no puddles on the roof.
Regular roof pitch
As a standard roof pitch is defined as the roof slope, up to which a roofing has proven generally as rainproof. This means that traufwärts running water normally does not penetrate. Examples:
- FZ - roof panels, German cover 25 °
- Slate, old German cover 25 °, 22 °, old german double cover,
- Concrete roof tiles, high-lying longitudinal fold 22 °
- Doppelmuldenfalzziegel 30 °
- Pantile 22 °
- Plastic plates 15 °
- Trapezoidal profiles, steel and aluminum 4-7 ° (eg, MAAS, Laukin )
- Industriestehfalz (eg BEMO, Kalzip ) 0.5 °
- Asphalt shingles 15 ° to 85 °, depending on the rafter length and shingle form
The standard roof pitch is also often referred to as minimum roof pitch. This is not quite right, because the term minimum roof slope would mean that this roof slope shall be less in any case. A roof can also be covered with a lower roof pitch than the standard roof pitch. As the rainy security then can not be guaranteed, then additional measures are required, such as a waterproof roof.
- Roof