I'm replacing a damaged beam under my house with bricks under each floor joist. The bricks are 15mm lower than the original beam. I've been told to use roof slates to pack the rest of the height.
I'm slightly skeptical due to slates being brittle. Could I use synthetic slates instead?
I've read about dry hard packed mortar but that isn't an option for me.
What other materials are used for packing in these instances?