כְּלִי עֵץ הָרָאוּי לְמִדְרָס שֶׁקְּבָעוֹ בְּכֹתֶל בְּתוֹךְ הַבִּנְיָן. קְבָעוֹ בַּכֹּתֶל וְלֹא בָּנָה עַל גַּבָּיו אוֹ בָּנָה עַל גַּבָּיו וְלֹא קְבָעוֹ עֲדַיִן מִתְטַמֵּא בְּמִדְרָס כְּשֶׁהָיָה. קְבָעוֹ בְּמַסְמְרִים וּבָנָה עָלָיו טָהוֹר. וְכֵן מַפָּץ שֶׁנְּתָנוֹ עַל גַּבֵּי הַקּוֹרוֹת קְבָעוֹ וְלֹא נָתַן עָלָיו אֶת הַמַּעֲזִיבָה אוֹ שֶׁנָּתַן עָלָיו אֶת הַמַּעֲזִיבָה וְלֹא קְבָעוֹ מִתְטַמֵּא בְּמִדְרָס. קְבָעוֹ וְנָתַן עָלָיו אֶת הַמַּעֲזִיבָה טָהוֹר:
The following rules apply to wooden keilim that are fit to serve as supports that were permanently affixed to a wall in a building. If they were fixed in a wall, but nothing was built upon them or something was built upon them, but they were not permanently attached to the wall, they are still susceptible to midras impurity, as before. If they were affixed to the wall with nails and then one built over them, they are pure. Similarly, when a mat was placed over beams, if it was affixed there, but a ceiling was not built over it or a ceiling was built over it, but it was not affixed, it is still susceptible to midras impurity. If it was affixed and a ceiling was built over it, it is pure.
