My Granddad died with a Will, does the house still go to probate?

Everything that was in your grandfather's name alone is part of his estate.   The process by which the assets of an estate pass on to the heirs or beneficiaries is called probate.   Since there is a will, you will have to retain an attorney to file a petition for administration with the Court.  This petition asks the court to admit the will and name you as personal representative.   Once you are personal representative, then you can go ahead and take the steps necessary to administer the estate.  Part of that administration is notice to the rest of the family.

Yes,the estate must go to probate so a new deed can be filed. The heirs must receive formal notice.  You are entitled to a commission as Personal Representative and can retain an attorney to assist you. Good luck.