Housetop (4)
I believe the answer is:
roof
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">housetop</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for roof that I've seen before include "Upper permitted limit" , "Canopy" , "Mansard is an example of one" , "One is angry when one hits it" , "Top covering of structure" .)