I have been working with Sketchup and Shapeways for a little while now (3 weeks.) I just finished working on a model that is not too large in my opinion, being 1.6in (4.1cm) x 1.6 x 5.9 cm (2.3in). When I originally downloaded it the sides were a little thick, at .0625 or so, even so I was shocked to have the price in ultra frosted detail at $266! Well, this model is essentially just a glass as the bottom is totally open. I spent time thiining the walls down to just .012in or just a hair over .3mm and when I uploaded the model it cost even MORE money to print $275 for FUD. Can someone please help as everything that I have says the model is hollow, but Shapeways apparently doesn't think so.
Did you set the units correctly when you uploaded the model? You can check the size on the model page directly under the model image.
If you open the file in Netfabb, you'll see that all the various faces in the model are their own shell.. you need to try to join them together properly. As your model stands now, the upload software is sealing the bottom opening of the building, making the whole thing solid and therefore expensive. Several other forum posts here suggest that you first try to clean it up in Sketchup using the Solid Inspector plugin.