Mass timber floors are being used increasingly in both mass timber and hybrid timber buildings due to its dry and rapid construction. Bare mass timber structural slabs have relatively low impact sound insulation performance. Though certain floating floor assemblies on mass timber slabs can provide adequate single number ratings, such assemblies are mainly effective in the middle to high frequency range. This paper will provide an overview of the research on the impact sound insulation perforamnce of mass timber floors with exposed ceiling and floating floor assembies conducted at the Universtiy of Northern British Columbia. The test data of bare mass timber floors, with continous floating concrete toppings, with raised discrete floating floor assemblies will be presented and compared. The effect of interlayer, concrete thickness and excitation sources on the single number ratings and frequency spectra will be discussed. Recommendations for future reseach will be given based on the discussion.