We have developed a facile, low-cost SiO2 physical vapor deposition technique based on the thermal decomposition of polydimethylsiloxane (PDMS) at atmospheric pressure. This technique allows for deposition of ultrathin, conformal, pinhole-free layers of SiO2, using a standard muffle furnace. We demonstrate the coatings’ uniformity and conformality on Si substrates, ZnO thin films, and high aspect ratio ZnO nanorods. We observe a linear relationship between thickness and source material mass (0.25 nanometers SiO2 per milligram of PDMS).