Mine are 1 1/2" thick. So 1/4" pvc inside and out and 1" foam insulation in beteen. I epoxied pvc vertically however so when reinstalled the screws would have plenty of material to go into. In other words, the fasteners are not going into only 1/4" of pvc. I did the same at top and bottom. I paint pvc without priming. I have found that if you prime the pvc, it doesn't pass the scratch test. Simply sand with 320 and sprayed. As far as the edges, I chose to put teak trim because I am a brute for punishment,, but like a lot of wood trim on our boat. You can simply cover the ends with PVC and fair with thickened epoxy. I will attempt to post picures here but if not successful, send me your email and I will send.