Roof Pitch/Angle?

[2B]

Working on a project where it is requested to make / install a large sign (30 x 60) flat onto a pitched metal roof usig the metal roof as the frame and the angle of the roof so as people drive by on the road they can know what the business is.

Is there a chart/graph that correlates the pitch/angle of the roof to the distance of readability? Yes I am aware that there are more factors involved than just the roof angle. speed of travel, elevation compared to the roof, etc...
Needing somewhere to start though.

Thanks

 

[J Hill Designs]

doubt it. you can figure out how much the letter 'shrinks' as it gets angled back, and use that adjusted letter height with any of the multiple letter visibility charts available

 

[John Butto]

Roof pitch is based on the rise. 12" on the bottom and the rise of inches going up, 12x12 is a a deep pitch compared to 12x1 being hardly any rise. You can find out what the pitch by using a carpenter sq and a straight edge.

 

[bob]

Basic trigonometry. The pitch of a roof is usually expressed as the ratio rise:run. Run is usually expressed as 12. A 6:12 roof would rise 6 feet for every 12 feet of run or length.

The angle is the arc tangent or atan of the quotient rise/run.

The relative height of the sign and any text or image would be approximately the sine or sin of the angle.

For example, using same the 6:12 roof: 6/12 =.5. The atan of .5 is 26.565... degrees. The sin if 26.565,,,degrees is .447...
Thus a sign, and anything on it at a 6:12 pitch would appear somewhere around.447, or 44.7%, of the actual height if viewed straight-on.

 

[John Butto]

This is probably a 3/12 or 4/12 roof

 

[2B]

thanks for the formula. much simpler than I was making it out to be.

 

[James Burke]

A sharp pencil and a good old-fashioned drafting board can also get you there, even if it's a scale drawing. Then all you need to do is utilize the distance chart to tweak sizes.


JB

 

[mark-s]

4 and 12 is most common here in So Cal.
Back in snow country you`ll see alot of 6 and 12.

4 is the rise 12 being the run.

mark-s