Reference for Shabbat 85:1

איתיביה כופין קערה על הנר שלא יאחז בקורה בבתי גחיני דשכיח בהו דליקה

He raised an objection: A dish may be overturned above a lamp, that the beams should not catch [fire]? This refers to houses with low ceilings, for it is a common thing for them to catch fire. [He raised a further objection:] And likewise, if a beam is broken, it may be supported by a bench or bed staves?<span class="x" onmousemove="('comment',' I.e., the longsides of bedsteads. ');">¹</span>

Jastrow