“وَ” (wa)a joining word meaning “and.” It connects this word to what came before.Corpus grammarCONJ — prefixed conjunction wa (and).
“ال” (al)the Arabic equivalent of “the.” It makes the following noun specific.Corpus grammarDET — prefixed definite article.
“سَّقْفِ” (ssaqfi)means “By the roof” in this verse. It is a noun. a naming word. Here it is masculine, genitive.Corpus grammarN — genitive noun.