Is performing Tayammum required when wiping over a dressing (like a bandage or cast)?
Chapter on Tayammum
Al-Mughni
Book of Purification
Primary text
Wiping over a dressing does not necessitate Tayammum. This position is supported by the ruling regarding wiping over footwear (Khuff). Since the area covered by necessity requires wiping, and the excess part requires Tayammum, some scholars suggest combining wiping and Tayammum if the dressing exceeds the necessary area. Furthermore, if the dressing was applied when the person was not in a state of purity, Tayammum might be obligatory if one holds the view that wiping over it is not permissible in that state.
Supporting text
There is a scholarly debate regarding combining wiping (over the dressing) and Tayammum. Some scholars allow it based on the Hadith of Jabir concerning the person who sustained a severe head wound (Shaja), suggesting that where wiping is prescribed, Tayammum might be required for the excess portion, or when the dressing was applied without prior purification. The dominant view, however, is that combination is impermissible because it is a single location, thus rejecting the combination of two different forms of purification, similar to the ruling on footwear.