When you are installing eave protection and underlayment, you must use a breather-type (no polyethylene). The felts described in the application of standard shingles should be used under all wooden shingle or shake roofs. Ensure eave protection extends up the slope the required distance. When you are installing the breather type underlayment under shingles, tack it sufficiently to hold the underlayment in place until the shingles are applied.