Whenever someone wants to buy your house or you want to get a loan based on its value, you usually need an appraisal. That's not an issue with transferring your house to a living trust, as no money changes hands. Your trustee may have to appraise the property after you die, however, as part of managing your trust assets.
To transfer your house or an investment property to a trust, you have to write a deed. You as grantor -- current owner -- transfer title to the trustee, which with a living trust is usually yourself. A valid deed includes the date of transfer, your name as grantor and trustee and the legal description of the property -- which is how the property is described in county records, and not the street address. Then you get it notarized and file it. Some states have added requirements, such as a witness's signature.
The role of a living trust is usually to transfer your assets outside of probate or let someone manage your property when you're unable to do so. Both these jobs require that you name a successor trustee to take over for you. Her job will be guided by the trust documents you draw up. If all the assets go to one person, it's fairly simple, but if you're dividing up property, it's important to identify the house in the document and say who inherits it.
When you die, your trust gets you out of probate, but not out of estate tax. That's probably not a problem, because as of 2013 your estate must be worth at least $5.25 million to trigger estate taxes. If you do fall into that category, this is the point when your trust-owned real estate gets an appraisal. Your heirs also need to know the value of the house when they inherit it, because that will affect capital gains if they sell it.
Although the law doesn't require you use an appraiser, it may come in handy if your estate planning gets complicated. If you're trying to dole out your assets equally among your heirs, you need to know the approximate value so that you can divide them fairly. If your house has gone up in value since you bought it, say, dividing it among your children might be fairer than letting one of them inherit all of it. Some appraisers offer a shorter, less-detailed report than you'd need for a mortgage.