Family buy-to-let mortgages

A family buy-to-let mortgage is a buy-to-let loan on a property let to a close relative, such as a parent, child, sibling or grandparent. Parents buying a home for a student or adult child to rent, or children buying a home for an elderly parent, are common examples. It is a niche part of the buy-to-let market.

The difference from a standard buy-to-let mortgage is the tenant. Because the borrower or a close family member is living in the property, many lenders treat the loan differently, and some do not lend on family lets at all.

Families often consider this route when a relative cannot get a mortgage of their own, or when the owner wants to keep a property in the family while helping someone with housing. The mortgage choice then has to reflect both the investment side and the family arrangement.

A buy-to-let mortgage where the property is occupied by the borrower's close family is generally a regulated mortgage contract rather than an unregulated buy-to-let loan (FCA Handbook PERG 4.4, accessed 20 Oct 2026). The lender then has to follow FCA mortgage rules, including affordability checks on the borrower as well as the rent.

This is separate from consumer buy-to-let, which covers accidental landlords who did not set out to be in business. In both cases the borrower has more protection than on a standard buy-to-let loan, and fewer lenders offer the product. How standard and regulated buy-to-let differ is covered in the guide on how buy-to-let mortgages work.

Lenders still look at the rent, but many accept a rent below the market level on a family let and make up the difference with the borrower's own income. Others insist on a full market rent and a proper written tenancy agreement. The approach varies, so the same case can get different answers from different lenders.

Because the loan may be regulated, lenders also check that the borrower could afford the mortgage if the relative stopped paying. Income, existing commitments and the borrower's own home mortgage are all part of the assessment. How the rent and loan work together can be tested on a buy-to-let mortgage calculator before applying.

Where below-market rent is accepted, the lender may ask for evidence of the borrower's income and a lower loan-to-value. The rent agreed with the relative should still be realistic and paid regularly, because the lender treats the loan as relying partly on that income over the full term.

Lenders that offer family buy-to-let usually set out which relatives count as close family, the minimum deposit, whether below-market rent is acceptable and whether the borrower must own their own home already. Some require a written tenancy, and some limit how many family lets one borrower can have.

The usual buy-to-let checks still apply, including the property valuation, the borrower's credit history and the source of the deposit. Stamp Duty Land Tax at the higher rates normally applies when the borrower already owns a home (GOV.UK, Stamp Duty Land Tax: higher rates for additional properties, accessed 20 Oct 2026). Comparing lender criteria on a family case is easier through a broker who handles regulated buy-to-let.

Alternatives include a joint mortgage with the relative, a guarantor mortgage, a family-assisted mortgage where savings or property are used as security, or a gifted deposit so the relative can buy in their own name. Each option affects ownership, tax and responsibility for the loan in different ways.

The right structure depends on who will own the property, who pays the mortgage and how long the arrangement is expected to last. Legal and tax advice is often needed alongside the mortgage, especially when a property is bought for a child or an elderly parent.