Moving away from Commensalism

This post is a random stream of consciousness regarding my topic - I am trying to brainstorm in which ways a host building may benefit from an attached structure beyond just the addition of space.  The reverse is quite quantifiable, especially in a parasitic relationship but that is what I am striving to move away from.

So, I am looking at a number of things which a host building could gain from its partner.

1. Structure - although a host building may need to support its partner there is possibilities to add additional structure to the host through its partner.  I am thinking in terms of exterior supports but not to the extent of just placing one structure above the other - there needs to be a connection of sorts and adding a building above with its own structure is only an expansion of space.  One of the examples posted in my competition was a nurse log.  Therein, the growing tree roots extend through the nurse log to the earth, invariably adding structure to the rotting log.  The roots also take nutrients from the fallen tree.  To apply this to the built environment, supports would also have to supply resources to both entities (although I am hoping the existing structure is not just a rotting fallen down building...).
2. Decreasing in some manner some of the existing dead loads of the host in order to offset some of the additional weight of an attached structure.  An idea I have been floating for this is looking at snow loads and how I could decrease them with the shape of the roof (wind loads perhaps as well).  Take for example a flat roof with parapet, a structure could be added with angular walls/roof in order to decrease the area where snow would collect and therefore lessen the load.
3. Efficiency.  The efficiency of the existing building could be increased through a number of means.  The typical parasite just leeches off its host; when discussing buildings this is primarily the heating, electrical, plumbing, etc...  My goal is to protect the existing building and its original components.  One way a partner could benefit the host without disturbing it could be to add additional energy efficiency.  Perhaps a structure could be mounted on the wall or roof of a building.  The added structure could provide an additional layer of protection from the elements - such as a higher R value roof/wall which would add to the existing wall/roof of the host building.  Furthermore, any additional structure allows for the implementation of newer/more efficient materials which would benefit an older existing structure.

  This is, in my mind the most important aspect if I want to focus on Mutualism: it is that both entities must benefit from the relationship.  If any readers have some concepts of how buildings can benefit from eachother please let me know.

W

Competition #1

Here is a little post to help us all, build your comment base and help direct my research - all the while with a chance to win a little something...  I am opening up a competition based around my research proposal; it is as follows:

I am looking for pictures of parasitc or mutualistic relationships in nature.  So, for one week I am requesting people post either links, pictures or sketches of such relationships.  Entries are limited to one per person so make your posting worth while.  Entries will be judged by myself and could have some influence on how I develop my project so you will not just be competing for the reward described below.  Due to delivery issues, I will have to limit entries to those I can physically present with the award.  Only those in BC's South West Interior are able to win, however anyone else may help the discourse and put any pictures up.

The prize, for one winner, a six pack of beer of your choosing within reason.  Not bad for what might only take you 5 minutes of searching google images...  It may help your chances if you explain the example in a brief sentence or two as well.  Here is an example:

Post early and often and please keep the entries appropriate for classroom-like discussion.  Stay tuned for more similar competitions.

W