Concrete Blocks......

[The one 8,393]

Aye they look like breeze blocks we built our garage and extension with them and you do need to render them the frost took the facing render off thei front step and the blocks crumbled so we had to replace them but I put a air vent in this time

[Flacko 1,732]

They are 7n blocks for use in block and beam, or below dpc for footings.they can be used any wher but heavy so most wrk above ground level ash blocks 31/2n good solid block and very dense like some on here lol.

[Rabid 1,936]

Not all block and beam floors are 7n, some are only 3.6n either way those blocks will not be insulated, but are suitable for building with depending on the use, 7n are often used to bring footings up below ground as they are a load bearing block.

If you are planning to use the outside above ground then they will either need sealing or rendering. Not a cheap block to buy now, I am paying around £7 a m2 and that's cheap compared to some places

[Truther 1,579]

Both sets of blocks in the picture are 7n, the ones on the left are just "rough" for general use and certain load bearing work, and the ones on the right are "paint grade" only real difference is paint grade are finer aggregate, the red paint stripe tells you that. Neither are very good for kennels because of their "U value" they don't hold heat in very well at all, you can't use either above DPC in domestic dwellings on external walls for eg, heat loss, certain exeptions apply though.

 

You could build kennels, but they would need expensive foam board type insulation, then a ply skin over that internally, rendered or well painted externally for weather proofing or they will absorb water then break when it freezes in winter, but all blocks are the same, no matter what quality.

[slip lead 862]

The smooth blocks are facing blocks

Used for face work.