This strategy is where you buy a property that requires some work, refurbish the property and rent it out or refinance the property and take your money back out.
The essence of BRRR investing is to find a property where by you can add value. By adding value, you can then refinance the property and hopefully recycle most or even all of your money back out.
It also works well with buy to let as it enables you to build a very large portfolio quicker as you can purchase properties at discounted price due to the property being a little tired. Adding value can be done by undertaking minor refurbishment for example; putting in a new bathroom, kitchen, carpets, paint etc.