I've seen really beautiful home-made doors that do an excellent job, but unless you've got great building skills, I don't recommend it.
Pre Hung Insulated Exterior Door:
It's cheaper and faster to buy a standard pre-hung insulated exterior door. This is because the key to the door is that it seals up tight and that's not so easy to get right! If you leave the smallest gap in your door, much of the effort you put into insulating and sealing up the rest of your structure will be wasted.
Heres a few tips to get the most out of your door:
- Make sure your door opens to the outside world (make sure the cooler is up a bit from the surrounding ground level so the door can swing freely)
- Glue another layer of 2" rigid foam to the inside of the door (it'll break down in the sun on the outside).
- Remove the bottom metal piece of the pre-hung doors so it doesn't dam up the water inside your cooler (and that means you have to cut the sides of the door down so the bottom stays flush against the floor). inner floor. **This is only important if you plan on hosing out the cooler, otherwise keep the threshold in place.
- They sell door sweeps which can really help seal up any drafts which may be sneaking in at the bottom of the door, like this one here:http://www.homedepot.com/p/Frost-King-E-O-1-3-4-in-x-36-in-Brown-U-Shape-Door-Bottom-Sweep-with-Drip-Cap-U37BRH/100666120?MERCH=REC-_-PIPHorizontal1_rr-_-203231840-_-100666120-_-N.