Two concrete foundations, one for the watt balance (64 tones) and one for the gravimeter (10 tones) have been cast in the new watt balance laboratory. Each is isolated from the main floor of the building but remains in lateral contact with the earth to avoid low-frequency swinging motions (excited by surface Rayleigh waves). The horizontal and vertical rms velocities due to ground vibrations are 1 µm s^-1 and 0.76 µm s^-1, respectively, (for 0.003 Hz < f < 100 Hz). These values are ~5 and ~10 times lower, respectively, than the corresponding rms velocities measured at the present location of the watt balance apparatus in 2010, and on the optical table which supports the watt balance.