Barn weathering

As always, I get ideas as I'm doing something and decide to strike out and see what I can do with the idea before the project is finished.

After getting the outer facade applied the structure, I got to thinking about how best to weather it?  I thought about washes but with cardstock I wasn't sure it would be a good idea to apply something wet on it.  So I dug out my trusty Pan Pastels and started playing around with some on the scrap portions of the kit.

After getting an unseen area coated, I decided to go for broke and try the facade.

Here's the raw facade.

Here it is after applying some Pan Pastels.

Here are the four colors I used:  

Orange Extra Dark    Neutral Gray

Raw Umber               Raw Umber Shade

I sparingly applied the Neutral Gray in a random pattern.  Then applied the Raw Umber in the same way but a bit more heavier and blended the two together.  I used the Orange Extra Dark along the roof overhang to highlight where the sun didn't beat down on it.  The Raw Umber Shade being a bit darker was used along the bottom to show dirt splatter.

I'm kind of thinking about dry brushing or using a sponge to add some remnants of white paint?  

I'm also kind of wondering if I should use a darker gray since the area I'm modeling is not in a dry, arid climate?  The darker gray may give it a damper look with a bit more moss?