Thanks Sueellen
I think the Booklice/Paperlice link could be the answer......"may crawl in large numbers over stored papers, books, walls, furniture, and other materials in damp, warm, undisturbed areas in buildings especially during the spring and summer months. Sometimes they are found in newly-constructed dwellings containing uncured green lumber or plastered walls"..
As the link suggests they smaller ones seem to be lighter in colour. Let's hope the house dries out quickly!!
MCC