&quot;Every hole in the roof is a dagger through the heart of the house&quot;.  That&#x27;s a problem. Roofs, as building elements, suck.  Walls and foundations can last for centuries.  Roofs have trouble in 20-30 years.  Solar panels add unplanned loads to roofs and involve holes through them. Some tile roofs can&#x27;t even be walked on without damage. There&#x27;s no roof standardization.  Hence the problems of home rooftop solar.<p>Commercial roofs are in some ways more promising. They tend to be flat, and much stronger, designed to support air conditioning units and other mechanical systems. But they have other problems.  One big one is that the owner and tenant are usually different parties, and there may be complex tax shelter arrangements in place.[1] Negotiations become very complicated.<p>There&#x27;s interest in new roofs which are solar panels, and there are &quot;solar shingles&quot;, but those are not in widespread use yet.<p>[1] <a href="http:&#x2F;&#x2F;www.solarindustrymag.com&#x2F;issues&#x2F;SI1501&#x2F;FEAT_01_Commercial-Rooftop-Success-A-Little-Ballast-And-A-Lot-Of-Business-Sense.html" rel="nofollow">http:&#x2F;&#x2F;www.solarindustrymag.com&#x2F;issues&#x2F;SI1501&#x2F;FEAT_01_Commer...</a>