Curved roof pergolas are a luxurious design edition to any yard or patio. The elegant lines are truly no more difficult to build than a regular straight edge. There are many beautiful kits you can find such as the one in the photo above from Forever Redwood. They come complete with step by step instructions on how to build it along with all the attachment hardware needed. Boards are cut and stained according to the design you want and marked so that you are pretty much just putting slot A into tab B.
However, if you want to build the pergola yourself, a curved roof design is also an option and you shouldn't be deterred from working with the bowed roof pieces. From the example above you can see that redwood is an excellent choice for a pergola and will bend very nicely. Don't worry! You don't need to do any bending. A good lumberyard will be able to provide you with the curved pieces according to your required dimensions.
Notice that the ends of the curved rafters are kept with a straight cut. This is also true of other kits we've found as well. Once you have pieces curved and measured out for the correct arc, you really don't want to mess with cutting fancy edges at that point. Some designers think any fancy edges are overkill and it certainly does keep the focus on the graceful lines if you keep it simple. But the example above also looks beautiful with the fancy edges reserved for the straight beams and top level of rafters.
The curved roof might be a little bit more cost, but we promise it will not add extra work to your building project. In the end, it would be something that will provide an even more unique look to your pergola design.