Brillouin spectra due to thermally excited surface ripples (Rayleigh waves) have been observed on both porous and non-porous 6H SiC after deposition of aluminium coatings varying in thickness from 20 nm to 70 nm. The spectra were obtained at room temperature in a back-scattering geometry using a tandem Fabry-Perot spectrometer with a probe wavelength of 532 nm. The incident beam power was normally less than 50 mW in a focal-spot area of approximately 50 mum. Data were typically obtained for a series of incident angles varying from 20degrees to 80degrees. The surface wave velocity for the (1 (2) over bar 10) face of the non-porous material was 6000+/-200 m/s. The corresponding velocities for the (0001) face of the porous samples were in the range from 2400+/-100 m/s to 2850+/-50 m/s.