Reverse Slope Arbor Roof
I found three different methods for attaching the cloth that if the whole roof structure of the pergola has a slope would still work.
Reverse slope arbor roof. The gentle slope of a hip roof with its trapezoidal sides and pyramid like elegance is a graceful traditional design that pleases the eyes and can be constructed in a combination of various unique styles. The roof structure is considerably slanted downward to create a slope towards the end of a pergola. And being able to see the sky through the roof is so beautiful. They also come in 12 lengths if you have a bigger roof to cover.
If you are using shed roofs or gables for the roof you will need to consider the angle of the roof and ensure that the right angle is used for the pergola. The methods mentioned above for attaching shade cloth to the top of your pergola would still be valid for canvas materials making it suitable for heavier rain as long as there is enough slope to ensure they drain. With any luck this will eliminate the possibility of having to make any adjustments to the structure once it is finished. The clear pergola roof still blocks some of the sun about 10 so the patio still feels cooler than the non covered area.
A gable roof is shaped like an upside down v and is sometimes referred to as a dual pitched saddle saddleback or peaked roof. Clear roofing panels i used the suntuf 26 x 8 panels.