We currently have a brick mantle over our fireplace & plans are to top it with wood. The brick mantle currently is made up of 5 rows of brick, each stepping back 1/2" - 3/4" from the row above, then has flat brick face on the whole wall. The top row is 7" deep. Should I drill & insert dowels to adhere the new wood top? Or should just plain construction adhesive be used? Plans also include going down at least 2 rows over the brick with trim moulding on the new mantle.