Hi. I have been told I need to level an external lower threshold for sliding doors and increase height by 6mm. Is a sand and cement mix too thin? Will be fixing to brick and concrete. Thanks
Pretty thin for a mortar bed. It should work if you pva the surface with a mix of 50:50 pva: water, add 25% pva to the water for the mortar mix and lay the bed while the surface pva is still tacky. There are also epoxy based mortars which can be laid thinly
I’d look at a latex type Self Levelling Compound with added fibres for a job like this. On the off-chance you’ve got half a bag of flexible wall tile adhesive laying about, then this would probably work as an alternative.