Ah, yes, that mythical "cost to actually build."
As in, the cost to build things in ways that completely ignore regulations. Regulations about building materials that won't collapse, and won't catch fire, and won't give everyone living there cancer. Regulations about safe electrification; safe, clean, adequate water; wastewater systems that won't drown the lower floors in raw sewage.
Do you know about the Grenfell Tower disaster?
70 people died, 70 more were injured, and hundreds were left without places to live, because the builders didn't think it was important to follow regulations. So they could make an extra buck.
So tell us about what the "cost to actually build" is. Please. Just remember that cost isn't only denominated in dollars and pounds.