Brick identification

[bandejapaisa]

These engineering bricks have grooves on one face. Do the grooves serve a purpose ? Such as a better key for rendering over ?

How would i search for this type of brick, as the lower half of my property is rendered and I need some for an extension.

Alternatively, after Ive laid up to DPC with the engineering bricks, what other non facing brick would be suitable above DPC, but will be rendered.

Thanks

 

[opps]

Erm... photos may help.

 

[bandejapaisa]

Haha. Yeah I forgot the photo

 

[^woody^]

They may make a theoretical key, but you don't need to match these exact bricks. You could just take rake the joints to achieve the same performance, but a rough faced concrete block would be better.

 

[bandejapaisa]

Thanks. I'm not fixed on matching these exactly, just kind of curious about the grooves on one face of the brick too and what it's for