Doug,
I assume you mean if it is watered down to run through a spray system?? That is something I am working on, but currently, it's not there yet. We have been working with a pad applied product, but still need to tweak it. It starts setting up before a house could be finished.
We have had lots of inquiries regarding vinyl siding, so the market is there, but our product isn't. If it was more concentrated, it would be thicker ... like honey. Getting it on windows would be a bit messy, but should scrape off easily since our silanes make it adhere to vinyl and plastic and not glass.......at least I think.. (I need to spend more time in the shop). However, with the price you could get for renewing siding, the time to paper off the windows shouldn't be much of an issue, would it?