Hi, we're making our chimney hole bigger to install a cupboard inside.
I've installed a concrete lintel (see image attached) but there is too much gap between concrete and bricks so I've inserted slates and mortar to secure the lintel.
I'm told this is a sound approach; wanted to get second opinions here.
Pictures of gap (showing the slates in-between) are also attached.
Any comments?
Thanks.
ST