In the UK tournaments we have a mix of buildings on bases and isolated buildings.
Where a base is included, the usual practice is to declare the entire base to represent ruins or buildings (depending on the models), blocking LoS. Touching the terrain provides cover to shooting (in the same manner as touching AV), but part of the unit has to be mounted on the base to gain the cover save provided by the terrain. The only inhibitor to shooting is that you cannot shoot more than 10 cms through this style of terrain.
Where there are isolated buildings clumped together (counting as one 'piece' of terrain towards the 12 for a table) they are treated as separate terrain features, thus allowing the possibility of firing through the gaps in between. Here, touching the building also means physically occupying it, so the unit gains the cover save provided by the terrain just by touching it. If touching (occupying) a building you can shoot through it, though whether you can shoot through other adjacent buildings that are separate is discussed during the 5 min warm up.
Note,
- infantry touching (and occupying) a building or partially mounting a terrain base can nevertheless be picked up by transport without taking a DT test. However if the transport has to touch the building (or mount the terrain base) to get the infantry, then it has to take a DT test unless it moves cautiously (5cm) - Air transport always need to take a DT test if it touches terrain.
- Infantry have always had a 360 degree arc of fire, so the only inhibitors to shooting are caused by buildings and ruins features described above.
- We do not degrade buildings to become ruins through shooting (it is just too time-consuming in the tournament environment).
- All the roofs are left their natural black rather than red.