Insulation boards under Ceramic Tiles

[GrahamDIYer]

About to lay ceramic tiles in 50s bungalow with concrete floors (having removed Marley tiles and sealed old bitumen adhesive).

Is it worth putting a 6mm insulation board under the ceramics to prevent some heat loss? (dont wanna go 10mm + tiles as too much faff cutting down doors that much).

Any recommendations for boards, will any old insulating board designed for underfloor heating (which I'm not putting in) do the job?

thanks
G