With no loans, a 35 year term and room rental you qualify for a mortgage of up to €290,000 as a 92% advance or €255,000 as a 100% mortgage based on a salary of €60,000. With a self build you can borrow 100% of the build cost if you already own the site. There's no discrimination against single people and it's not a case of what you can hope for - a mortgage is a commodity the same as any other and you should shop around for the best deal.