Building a cellar- are aerated blocks waterproof?

[james1251]

I am intending to build a cellar under/in my garden.

I was thinking of building it from aerated blocks as they are cheap and easy to use. However I am worried that water/moisture may seep though the bricks. Do I need to seal them in some way? How can I do this if I don't have access the outside of the cellar (because the soil will be in the way, unless I dig a hole that is far too big and fill it in after)

Thanks

 

[^woody^]

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