What a joint home loan is, and why people take one
A joint home loan is one mortgage contract with two or more borrowers on it, where the bank combines their incomes to size the facility. The reason people do it is almost always the same: one income is not enough for the amount needed.
Banks assess debt against income, so adding a co-borrower who earns and carries little existing debt raises the approved amount immediately. That is the concrete benefit, and it is what drives most of these decisions.
What people rarely think through at signing is that a joint loan creates two separate bonds, and a great many treat them as one.
Debt and ownership are two different things
This is the sentence to reread before signing anything.
Being a co-borrower makes you a debtor. It does not make you an owner. Your name on the loan agreement and your name on the title deed or condominium ownership certificate are different documents, signed on different days.
The consequence is four possible positions, not two.
| Position | Must repay? | Owner? | Where it shows up |
|---|---|---|---|
| Co-borrower and named on the title | Yes | Yes | Couples genuinely buying together |
| Co-borrower, not named on the title | Yes | No | Parents helping a child qualify |
| Not a borrower, named on the title | No | Yes | A gift, or an inheritance |
| Neither borrower nor named | No | No | Someone paying with nothing in writing |
The second row is the most common and the most misunderstood. A co-borrower not on the title remains liable for the whole debt if the other party stops paying, while holding no interest in the property itself.
The fourth row is the most dangerous. A person paying every month while named neither on the loan nor on the deed has almost nothing to point to when a dispute arises.
Who can borrow jointly
Per the summaries published by AP Thai and DDproperty, the usual eligible relationships are:
- Spouses, whether the marriage is registered or not.
- Parents, and siblings by blood.
- LGBTQ+ partners, which many banks now accept.
For an unmarried partner, many banks have opened up, but the conditions are stricter than for a spouse and they often ask for supporting evidence such as photographs together, a joint deposit account, or a shared house registration.
Eligibility rules differ between banks, so ask each lender you intend to apply to rather than assuming the terms are standard.
The point most people miss: a co-borrower off the title still gets 100% on their own first home
The Bank of Thailand relaxed the LTV rules for joint loans explicitly: a co-borrower who is not named as an owner is treated as though they had not borrowed on that occasion, on the reasoning that the loan was not for their own residence but was help within a family.
In practice, where only one party to a first joint loan holds title, that contract counts as the first contract for the titleholder alone. When the other co-borrower later borrows on their own to buy a home, the bank counts it as contract number one, which means up to 100% LTV.
This matters enormously to anyone about to help a parent or sibling qualify. Signing as a co-borrower without going on the title leaves your own future first-home entitlement intact.
For the LTV rules and the measures extended to 30 June 2027, see the 0.01% fees and 100% LTV.
The interest deduction is divided among borrowers
Interest on a residential mortgage is deductible against personal income tax at the amount actually paid, capped at THB 100,000 per year, and on a joint loan that right is split among the borrowers, with the combined total not exceeding THB 100,000 a year.
Two co-borrowers therefore get THB 50,000 each, not THB 100,000 each. The ceiling belongs to the loan, not to the person.
The condition to read carefully: whoever claims must be named as owner of the building used as a residence, and must produce the bank's interest certificate as evidence.
The trade-off: on the title or off it
The two sections above pull in opposite directions, and this is where the decision should be made deliberately.
| Co-borrower named on the title | Co-borrower not named on the title |
|---|---|
| Can claim a share of the interest deduction | Cannot claim the interest deduction |
| A genuine co-owner with rights in the property | No rights in the property, though liable for the debt |
| The loan counts as their own contract for LTV | Not counted; their own later purchase is still contract one |
| Any sale or transfer needs everyone's consent | No power to block a sale |
A workable rule: if this is a genuine joint purchase and you intend to live there together, put both names on the title. If you are helping a relative qualify and do not intend to own, staying off the title preserves your own first-home entitlement.
Can a co-borrower be removed later
Sometimes, but not simply because both parties agree, because the bank is the creditor and the bank decides.
The lender assesses whether the remaining borrower can service the loan alone. If the answer is no, the request to remove a name is refused.
The usual route when removal fails is to refinance with a different lender in one name, which means starting the whole approval process again and paying a fresh mortgage registration fee.
Note also that removing a name from the loan does not remove it from the title, and transferring the title to one party does not automatically release the other from the debt. Both have to be done, separately.
If the relationship ends, whose house is it
As DDproperty summarises it, where no transfer has been made the house is joint property and both parties hold equal rights of possession, unless there is a written agreement, or it can be proved which party paid more.
"Can be proved" is the whole thing. Monthly transfers from your own account into the mortgage account are usable evidence. Cash handed over, or letting the other party pay everything, leaves no trace and helps you not at all in a dispute.
Three routes are commonly used: one party buys out the other and refinances alone; the house is sold and the surplus split after the debt is cleared; or both keep it, under a written agreement setting out who lives there, who pays, and when it will be sold.
What to put in writing before signing
An agreement between co-borrowers is not a document the bank asks for. It is the document that protects both of you when circumstances change. Cover at least six points.
- Who pays how much of each instalment, and through which channel so there is a record.
- The deposit, transfer costs and fit-out: who paid what.
- The agreed ownership shares, and whether they match the names on the title.
- What the other party may do if one stops paying.
- Sale terms: who has the first right to buy, and how the price is set.
- Who lives there, and whether a party who does not live there still pays the same.
One more thing to check is mortgage life insurance. A co-borrower without cover becomes liable for the entire balance if the other dies.
Frequently asked questions
Who can be a co-borrower on a Thai home loan
Generally spouses whether registered or not, parents and blood siblings, and LGBTQ+ partners, whom many banks now accept. Conditions vary by lender, so ask each bank directly.
Does being a co-borrower make me an owner
Not necessarily. Being a co-borrower makes you a debtor under the loan agreement; ownership follows the name on the title deed or condominium certificate, which is a separate document. A co-borrower off the title is liable for the full debt with no interest in the property.
Does a joint loan use up my first-home entitlement
Not if you are not named as an owner on that loan. The Bank of Thailand treats such a co-borrower as though they had not borrowed, so a later solo purchase counts as contract number one.
How much interest deduction does each co-borrower get
The right is divided among the borrowers with the combined total capped at THB 100,000 a year, so two co-borrowers get THB 50,000 each. The claimant must be named as owner of the building used as a residence.
Can I remove a co-borrower later
Sometimes, but the bank decides whether the remaining borrower can service the loan alone. If refused, the usual route is refinancing with another lender in one name, which carries a fresh mortgage registration fee.
After a break-up, who owns a jointly financed house
Where no transfer has been made it is joint property with equal rights of possession, unless there is a written agreement or it can be proved which party paid more. Pay instalments by bank transfer so a record exists.
If a co-borrower stops paying, must the other pay everything
Yes. Co-borrowers are liable for the whole debt, not half each. The bank may pursue any of them, and a default damages the credit record of everyone on the contract.
In short
A joint loan gets the approval through, but it creates two separate bonds, debt and ownership. The people who get hurt when a relationship changes are the ones who assumed they were the same bond.
Two numbers to remember: the THB 100,000 annual interest deduction belongs to the loan and is divided among the borrowers; and a co-borrower off the title can still buy their own home later at 100% LTV, because that loan is not counted against them.
Before signing, do two things: decide deliberately whether to go on the title, and put your agreement with each other in writing. Writing it costs an afternoon. Not writing it costs a lawsuit.
Model the instalment on the amount you are considering with our mortgage calculator, and browse what is on the market at properties for sale. Owners looking to sell can see our house sales service.