Here is a quick look at the pages in the White Dwarf that have the rules for both of the new terrain pieces.
You can also find a full video of the magazine at the link with an almost page by page view.
It's a medium building with 14 armour all around and has a Plasma Obliterator emplaced.
Plasma Obliterator 72" s:7 ap:2 primary weapon 1, massive blast gets hot
Plasma overheat special rule: if the building suffers a glancing hit due to the plasma Obliterator gets hot rule, then in addition to any other effects any unit embarked in the building suffers d3 wounds. These are randomly allocated.