Can I replace dense concrete blocks with aerated ones?

[lookieluke]

Hi,

I have a quick question. I need to replace a few DENSE concrete blocks in the inner leaf of a cavity wall (house built in 60's). Is it ok to replace them with standard aerated ones (3.5N/mm2)?

Many thanks in advance.

Luke

 

[tony1851]

If it's only a two-storey house, and the replaced blocks are not near any heavily-loaded beam ends, you can use the lightweight block.