Cracks are common in skylights. Well, the incidences of repair are lower of you use shatter resistant or tempered glass. So, if the glass cracks, what do you do? If the crack is severe, you cannot help but replace the skylight. Hiring a professional is recommended for replacing the skylight because the whole set up has to be removed and fitted with the new one. When the skylight cracks, you could end up with water leaking through your roof. So, until the professional comes over to repair it, you need to make a temporary arrangement. The easiest thing that you can do is to cover it up with a plastic sheet from outside. You can use a tarp for cover. Make sure that the edges are secured. Use tape to attach the tarp well. You can patch small cracks by yourself. Caulk is a good material to be used as a sealant. You can also use putty. These materials are easily available in the market. Buy some and get to work. Follow the manufacturer’s instructions. Every skylight has two layers of glass or plastic in order to ensure insulation. If only one of the layers is cracked, you don’t have to do anything. Such cracks do not leak. You can just let it be until the crack demands repairs. At the slightest sign of leak, seal it.