A: DreamLine recommends that the shower base that if the shower base that you choose is installed to the studs, it should be appx. 2" larger than your shower enclosure size. In the case of the Unidoor Plus shower enclosure that you have referenced, the appropriate shower base would be the 32" by 48" size. Hope this helps. DreamLine's Customer Support Team can be reached by phone at 866-731-2244 or by email at support@dreamline.com if you have any other questions or would like to discuss this further. We are available M-F from 8am-7pm EST and Saturday from 9am-5pm EST. Please give us a call and we can help you through any issue. Thank you for your interest in DreamLine