Techinical Background

Thermal Performance and Aesthetic Options Comparison with Conventional Precast

In some climates, having-an-understanding of the effects of heat and cold and learning to protect against them are keys to survival. In any climate, the ability to keep the extremes of the weather from affecting the comfort of built space is the difference between green construction and the way of the dinosaurs. 6D-BuildTech understands that a building which performs well structurally but fails to keep its inhabitants comfortable is still a failure, and we provide an insulated envelope that is not found in conventional precast wall systems.
We also understand that even a building which functions well, but is not beautiful, is a missed opportunity. And not an insignificant one: beautiful, well built spaces and neighborhoods inspire and uplift the people that live in them. The difference between that and something less need not represent a large expense.

The opportunity is to develop simple sets of architectural reveal and form liner systems and pigments to provide precision cast exterior wall blocks that offer variations in detail, texture, and tone. Those wall blocks combine in sets to build several architectural variations of the approved villa design.

This document describes how 6D-BuildTech will its building occupants cool, and how it will make the neighborhoods they live in both cool and beautiful.

Thermal Bridges and Solutions

The roots of 6D-BuildTech are in architectural and bridge engineering. We love a good bridge. But when it comes to thermal bridges, we avoid them like the plague. It doesn’t take a bridge engineer to understand a thermal bridge; it’s just a pathway for the heat or cold of an exposed outside face of a building to cross the thermal envelope and affect the temperature and humidity of the inside space. Because they work in direct opposition to controlling the comfort of the inside space, thermal bridges cost the occupant both money and the comfortable use of their space. The air conditioning seems to be running all the time, but the corners of the room are still hot and uncomfortable; that is the end result of thermal bridges.

Heat travels very quickly through steel, and more gradually through concrete. The rigid insulation that is embedded in precast walls is intended to act as a roadblock to that heat travel. So the ideal insulated wall system ensures that the insulation extends continuously across the entire wall, and it diligently avoids building thermal bridges where steel or concrete cross the rigid insulation and violate the thermal envelope.

Consider a conventional precast insulated wall solution. It’s common for the internal insulation to be stopped short of the joints along all four edges, so that the internal dowels for field welded plate or bar connections can be embedded in concrete.

So, because of wall connection detailing requirements, a typical conventional precast detail (Fig. 1) seeks adequate structural performance at a heavy cost to the thermal performance of the building. Even the structural performance of this detail is less than ideal, because the field welded joint relies on embedded dowels that are very near one face of the wall. In an extreme loading, these connections would tend to simply tear out of the face of the wall.

The conventional detail shown here leaves the bottom 400mm of the wall completely un-insulated, forming a thermal bridge so wide that the insulation is rendered nearly useless - as heat migrates across the wall and up the inside face.