Prescriptive Method

Hi Stephen, in addressing the first question of lowering your VLT x WFR below 0.18, unfortunately there are limitations to using the prescriptive method. The prescriptive method doesn't address added daylight features, such as light shelves, exterior vegetative shading, or overhangs. While your calculations may be indicating that you are above 0.18, the reality of the on sight conditions may be different. I would suggest either doing a computer simulation or hand held light measurements. However, the deep exterior overhangs and shading from exterior vegetation may lower the amount of daylight that enters in the space. I am interpreting your second question as asking whether exterior overhangs and or vegetation can count as glare control. It sounds like you have a good case. The Reference Guide already recognizes exterior overhangs as a "fixed exterior shading device". You might want to write a CIR for your project if you want to also include the exterior vegetation.