Daf Yomi - Sukkah 14/15 - Beams and Potters

The Gemora on daf 8 stated that it was common for a potter to have a hut inside another one. Rashi explains that the inside hut cannot be used as a Sukkah because since the potter lives there all year, it is not discernable that he is dwelling in the hut for the sake of fulfilling the mitzvah. It is evident from Rashi that is not invalid from the Torah, rathe it is an injuction from the Sages.

The Gemora on our daf (14) rules that one cannot fulfill his obligation of sitting in a sukkah where the s'chach consists of beams larger than four tefachim. This is based on a decree that this sukkah would be similar to sitting inside his house. Rashi explains that one cannot fulfill his obligation by sitting in a house for the Torah states 'sukkah' and not his house where he resides all year.

It would seem that there is a contradiction in Rashi regarding the disqualification of sitting in a house, if this is invalid only from the Sages or is it unfit from the Torah?

Rabbi Y. B. Solovetchik explains the difference between the two cases. Regarding the potter's hut, the s'chach appears to look like s'chach of a sukkah, not of a house and therefore it is valid min haTorah. The Sages disqualified this hut because the person resides there all year. However by the beams, the roof appears precisely the way a house would look and therefore it retains the status of a house and therefore the Torah disqualifies such a sukkah outright.