I am planning to knit a fairly large rug from Lopi wool and am wondering if anyone knows if I can vacuum this rug for cleaning? Dh suggested we felt said rug to make it more vacuumable. That is an option, of course, but I am also wondering if I can simply vacuum it if I don't decide to felt it.
Also, if we do decide to felt it, can we felt it with a steam cleaner (with just water) or do I need to throw it in a huge washer?
Or maybe it doesn't really matter. What I'd be very concerned about is that the brush in your vacuum cleaner would likely pull a stitch, tangling it around the vacuum's brush roller and totally mucking up your lovely rug.
Instead, I think I'd go the Woolite-in-the-Bathtub route every so often. In between times, maybe you could shake out the sand/dust/whatever out the back door.
Your work deserves the best.
PS - I haven't felted any of my work, so can't address that part of your question.
You could suck up the dust and grit regularly with a Dustbuster-type vacuum, which has no brushes, and wash it only when really necessary. Wool generally doesn't attract dirt too badly, so the rug will probably not need frequent washing. But I still would not use a Lopi rug in a high-traffic area; the wool is loosely spun and might pill or mat if it's stomped on a lot.
The author of "The Knitted Rug" suggests soaking wool rugs in cool water and pH-neutral yarn wash in a washing machine, then switching to the spin cycle. Do NOT let it go through the agitation cycle unless you want it to felt. (A normal household machine may not be big enough for the rug you're planning, though.)
Steaming is a good way to block a wool rug, but it won't felt it; you need agitation for that.