I'd like to promote the link to a paper published by Dr Keith D. Lowe 罗金生 of the Tsung Tsin Association of Ontario:
Lowe KD. Heaven and Earth—Sustaining Elements in Hakka Tulou. Sustainability. 2012; 4(11):2795-2802.
The paper is published by the Multidisciplinary Digital Publishing Institute (MDPI) on this page on their website. From here you can download a PDF of the paper for free. I have already learned something new from the first page - that I was using the term 'tulou' to mean the roundhouses when in fact it can refer to buildings of other design as well. Hope you enjoy finding out a bit more about our Hakka architecture.