Can I just paint my roof white?

Unfortunately, installing a white roof isn’t quite as easy as opening a can of paint. Most roofing material manufacturers (including manufacturers of asphalt shingles) will not extend their warranties to roofs that have been painted or covered in some way. Many low-sloped (i.e. almost flat) roofs are covered with elastomeric coatings that are specifically designed to withstand weathering. These coatings can be painted on, which is why you see pictures of people painting their roofs with rollers.