Muscle mortgage is the colloquial term used to describe home improvements. In other words, everything that you or your family and friends can do yourself when you build a house. If, for example, you do the tiling or painting or have someone in your circle of friends who can install the electricity, you can save the money that you would otherwise have to pay to the relevant trades. That reduces your acquisition costs. And this means that your loan amount can be lower, which, in turn, means better conditions — i.e., lower interest rates.
However, you can't give yourself a guarantee on your own work, which is why you should think carefully in advance about what you can and would like to do yourself, and for which work you would like to commission the relevant trade so that you are covered in case of doubt.
In our podcast episode, you can also find everything about acquisition costs and incidental acquisition costs. Feel free to listen in: