Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Use of free and clear houses as Collateral
Any sensible lender will require a lean lien against your formerly-free-and-clear property, and will likely require an appraisal of the property. The lender is free to reject the deal if the house is in any way not fitting their underwriting requirements; examples of such situations would be if the house is in a flood/emergency zone, in a declining area, an unusual property (and therefore hard to compare to other properties), not in salable condition (so even if they foreclose on it they'd have a questionable ability to get their money back), and so forth. Some lenders won't accept mobile homes (manufactured housing) as collateral, for instance, and also if the lender agrees they may also require insurance on the property to be maintained so they can ensure that a terrible fate doesn't befall both properties at one time (as happens occasionally). On the downside, in my experience (in the US) lenders will often require a lower loan percentage than a comparable cash down deal. An example I encountered was that the lender would happily provide 90% loan-to-value if a cash down payment was provided, but would not go above 75% LTV if real estate was provided instead. These sort of deals are especially common in cases of new construction, where people often own the land outright and want to use it as collateral for the building of a home on that same land, but it's not uncommon in any case (just less common than cash down deals). Depending on where you live and where you want to buy vs where the property you already own is located, I'd suggest just directly talking to where you want to first consider getting a quote for financing. This is not an especially exotic transaction, so the loan officer should be able to direct you if they accept such deals and what their conditions are for such arrangements. On the upside, many lenders still treat the LTV% to calculate their rate quote the same no matter where the "down payment" is coming from, with the lower the LTV the lower the interest rate they'll be willing to quote. Some lenders might not, and some might require extra closing fees - you may need to shop around. You might also want to get a comparative quote on getting a direct mortgage on the old property and putting the cash as down payment on the new property, thus keeping the two properties legally separate and giving you some "walk away" options that aren't possible otherwise.  I'd advise you to talk with your lenders directly and shop around a few places and see how the two alternatives compare. They might be similar, or one might be a hugely better deal! Underwriting requirements can change quickly and can vary even within individual regions, so it's not really possible to say once-and-for-all which is the better way to go.