Roofs or rooves?

The angles of the roofs or rooves of the ancient Knockhall Castle and the less ancient, but equally ruinous, Knockhall farm buildings.

The old brain must be getting frayed around the edges because I couldn't, for the life of me remember whether the correct plural of roof is roofs or rooves. A visit to the Oxford English Dictionary suggests that roofs is normal, but rooves acceptable. In passing I was intrigued to read that roof is derived from the Old Icelandic hróf meaning a boat-shed.

It's a real struggle keeping a boat-shed over our heads in these days of banker-induced penury!