Calculating U-Values

[borderfox]

I have the BRE U-Value Calculator. However, there are still some basic materials that are not listed. Is there a list out there of the conductivity/resistance of basic building materials?

Also, when it comes to lightweight/medium/dense concrete blocks, in what situations would you use one as opposed to another?

 

[jeds]

The table on this site might help.

http://www.learn.londonmet.ac.uk/pa.../building_fabric/properties/conductivity.html

As for type of block. The first factor is loading - the block you use must be sufficient to take the load. The second factor is heat loss - aerated blocks are generally more expensive but will give you an advantage on the overall U-value. Third is cost - you would obviously want to select a block that is not disproportionately expensive. Fourth is sound transmission - the block you select can have a significant effect on sound attenuation.

I also usually try to select blocks that I know are readily available from local builders merchants. There's nothing more annoying for contractors to have to order blocks and wait days for delivery because they are an odd specification.

There are other factors but these are the most important ones.