What block to use ??????????????

Discussion in 'Builders' Talk' started by collectors, Jun 16, 2014.

  1. collectors

    collectors New Member

    Hi, we are building an extension with a brick outer & block inner & 100mm cavity, but not sure on which inner block to use .

    This is for a bungalow with a pitched tiled roof, so there will be some weight. I am assuming a 440mm x 100mm x 215mm 7n block is right, but can we use the light weight version for this as I am not sure what the difference is seeing as they are both rated at 7n.
    If you found a preferable make to use I would be grateful for the make & type.





    Hope you can help. (Thanks)
  2. Phil the Paver

    Phil the Paver Well-Known Member

    The really light weight one's are only 4n ain't they???.

    Use what ever one you wish, if you are laying them then choose the one your happy the move about all day.
    FatHands likes this.
  3. robbo69

    robbo69 New Member

    I Would not use thermalite blocks as they crack when your building moves my mate built his double extension and got a crack from top to bottom inside,got in touch with manufacturer told him it was normal movement (the mix was 6 to 1 ) ready mix so it was not to strong either go for 7n concrete inside and out but you must have a fully filled 100mm cavity to regain your thermal value.There are lite concrete blocks I think they are called flycrete they have strength of concrete blocks but also have thermal value they are more expensive than concrete

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