Building with concrete block – good or bad?
GBA Editor
| Posted in Green Products and Materials on
We are looking at something like the Lite-block made in Houston which can be done by a homeowner. What type of roof should be used with this system – metal beams/roof or standard wooden trusses? Would like info on the ease of building with this material for a homeowner and the green factor.
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Replies
Doris,
There really is no limit to the roof-framing options on a concrete-block building. Conventional sawn rafters, wood roof trusses, or steel roof framing are all possible options.
Concrete block walls are not subject to termite attack. Of course, any wall system — including concrete-block walls — must include adequate insulation. For energy efficiency, the type and thickness of insulation is far more important than the choice between wood framing and concrete-block construction.
A roof made of structural insulated panels (SIPs) would be my choice. If you pay attention to the details at the roof wall connections, you'll end up with a very tight house. You could still have a flat ceiling with your air handler and ductwork above, and you'd bring it inside the envelope and reduce your duct leakage to zero.
Regarding wall insulation, make sure you do more than just fill the cells of the blocks. That buys you very little improvement in R-value because of all the thermal bridging through the block webs. Put continuous insulation on the outside of the house, and then you get the benefit of the thermal mass, too.