Hi Mark & welcome to the Forum!
When we did Flussgarten the ´construction department´ was not my area of responsibility. The buildings came from Dave O´Brien, Kevin, Peter, Colin, Bob, Dale and Adrian. At least three of them are members of the Forum so maybe they will comment.
When Adrian and I did the Sedgemoor game at Partizan he supplied the buildings some of which(I think) appeared at Flussgarten. They are resin or plastic, very well painted, suitable for period 1300 to perhaps 1850. They are manufactured in China and sell painted for between 12 and 15 pounds. I think there are up to eight in total in the range. If you look on the Newark Irregulars site(go to links here) I know Richard Tyndall took a few pics of the Sedgemoor game and so you may see them in there. I will buy some when I can find them!!!
In the past I would have bought Hovels or scratch built in fact many of the buildings LoA previously used were scratchbuilt(not by me!
) but it´s really not worth it when you can buy something jjust as good for under 15 quid.
Cheers
B