Incorporating more than one wall type in a section of external wall using DDB

Question

On typical single storey warehouse buildings where blockwork cavity walls are often used for the lower section of external wall, and either single-skin or double-skin metal sheeting is used above the blockwork walls up to the roof line, how can this be modelled using DDB? 
 Would it be possible to add a sub-surface to an external wall in the same way as a window or door?

Duncan Brown · Accepted Answer

Hi Brian - I'm afraid that any single surface can only contain one wall type. A common method of creating warehouse spaces, however, is to draw them on two floors and connect them using a very very high U-value floor/ceiling. This would allow you to define the upper floor using a different wall type and the floor/celing shouldn't impede the heat flow. 
 
The alternative to this is to finish your project using one wall type, then break the project out into "room data" mode and manually add surfaces at the correct orientation. You should be careful to back up your project before switching to "room data" mode. 
 
Regards,