If you have an asphalt roof, yes, you can install new shingles on top of existing shingles. The process is called re-roofing, and while possible, professionals do not recommend it.  You should only consider re-roofing if your underlying roof structure is in good condition. The process is faster and less expensive than a roof replacement, however; it presents many more cons than benefits, including:    ◉ Adding weight to your roof ◉ Impossible to inspect the underlying roof foundation without prior shingle removal ◉ Shingles are not designed to be installed over existing ones  ◉ Only works for asphalt roofs ◉ Re-roofing does not last as long as a full replacement