Concrete vs. Wood Frame

[Wooster]

What are the environmental benefits of concrete buildings over woodframe?

In:

Energy Efficiency

Durability

Environmental impact of extraction from the natural environment.

Any links to data or information would be very helpful

[Calgarian]

I would say that wood is more efficient in every aspect except durability. Wood uses trees, but concrete requires large quaries. Concrete has more embodied energy (the energy used in manufacturing the product) than wood. Concrete also has more thermal mass than wood, so it takes more energy to keep it cool in the summer and warm in the winter (a big reason that the Bow will be steel). I don't have any sources, but that is what I learned in school.

[Wooster]

But thermal mass is a good thing. It keeps heat in in the winter and keeps heat out in the summer, thereby reducing energy use. Lower thermal mass more closely resembles the outside temperature. So if it is hot you need A/C, cold outside you need more heating.

[Calgarian]

Originally Posted by josh white

But thermal mass is a good thing. It keeps heat in in the winter and keeps heat out in the summer, thereby reducing energy use. Lower thermal mass more closely resembles the outside temperature. So if it is hot you need A/C, cold outside you need more heating.

you are right, partially. In a climate such as a desert, you want thermal mass in the building to absorb heat during the day, and will keep a building warm at night when it gets cold outside. In a climate like Calgary where the temperature varies a lot, thermal mass makes it difficult to heat or cool the building when the temperature shifts. My apartment building for example, is 8 storeys of concrete. During the winter, the floors and walls lose a lot of their energy and are perpetually cold, no matter how high I turn up the heat. During the summer when it is hot, the concrete absorbs and holds the heat, so the building is perpetually warm, no matter how cool it gets at night, the building is still warm in the morning. Basically thermal mass increases cooling loads in the summer, and increases heating loads in the winter.

[Kelvin]

Timber is not as friendly as one initially supposes. Take for example, it has to be cut, transported, milled, dried, preserved, packaged, retailed and ultimately built into a structure. Lots of work. Also, it is much less efficient (strength to weight) as compared to concrete thus requiring more material than say if it were "engineered". One can process wood so as to only use the good pieces (engineered lumber, glu-lam, etc), but again more processing = more energy and greater by-product and more habitat lost.

Portland Cement requires extraction, crushing, kilning and processing. Quarries use land space true, but at a fraction of what timber harvesting requires. The Portland cement is really the only component which has to make long travels and is almost always handled in large volumes. The aggregates and water are generally always readily available locally. Add a small cost associated with supp. admixtures.

Too many variable to consider really...

[Calgarian]

To be honest, I would say steel is superior to both.

[wong21fr]

None are superior to the other. They all have their strengths and weaknesses and it really depends on what kind of structure you are building that is really going to determine what is the ideal material from both a structural characteristic and a economic characteristic.