Believe it or not it is easier to build a DIY permanent awning than it is to build a retractable one that works as smoothly as a store bought kit. Also, I think you will find that you will end up spending more on the supplies to build it than you will on purchasing one. I have a strong DIY streak in me so I hate to rain on your DIY parade but this is a situation where you might do better to buy.

I really have my heart set on a retractable awning since I don't want the inside of my house to be shaded all the time. But, since I live in a very hot area, I do need something to shade the house during the sweltering summer months.

We've had a shade tree canopy for 2 years and love it. Sunbrella is a good quality outdoor fabric. Water doesn not seep through the fabric. The fact that it comes in sections allows longer projections and flexible installation - yes, rain will fall beteen the panels if left open in the rain. So if you want to sit outside in the rain that is not a good choice. One thing I like about them is that they will disengage in wind if you happen to leave it open and storm kicks up, which happend to us about a month a go. 70 mph winds and the canopies were fine.

Landscapers - it sounds like your complaints about the shadetree canopies are that it did not fit your desired application, which is your fault for selecting the wrong product if it was not acceptable. We've been very happy with ours, but it may not be for everyone.