I just wrapped up the Design Development phase of the library project I’m currently working on. It was amazing to me what happened when we started value engineering after the schematic design came in quite a bit over budget. As we began to make changes, one decision would effect several other parts of the building and then those decisions would effect other parts and so on and so on.The most significant design decision we had to change was to use a more traditional HVAC system instead of an energy efficient displacement system. From a LEED standpoint, the displacement system is a great choice because it uses less energy and can use a smaller air handler. When it came to the budget though, we simply could not afford the cost of the structural floor system required to put the ducts under the floor.

The first counter effect we saw was that by moving the ducts to the traditional overhead position, the roof was not high enough to accommodate them. Therefore the first big change we had to make was to raise the height of the entire building up 2 feet. The second counter effect came after a discussion with the client. Some the previously built libraries in San Antonio had used exposed HVAC ducts, and they didn’t like that look. Therefore, our next change was to put a ceiling in the building.

Then came the second tier of counter effects. After putting a ceiling into the building, the full height glass we had on some of the walls is looking into an enclosed plenum space. So then came the decision to added fritted glass above the ceiling line. And the list continued on and on. It wasn’t until I took a moment to look back at all the changes we had to make, that I realized how one change could affect the entire design of the building.