This is a situation where the Residential Tenancies Act does not set out any clear guidelines or provisions as to how to deal with the tenant and getting work done in the unit. It is usually up to both parties to try and work out an arrangement where the tenant may have to move out temporarily while the work is being done, in which case you would provide a rent rebate or offer to pay for the temporary accommodations. Whatever arrangement you both agree on, make sure to put it in writing to avoid any misunderstandings.