A heavy-weight asphalt roofing felt made of a specially formulated organic sheet which has been fully saturated with waterproofing asphalt. This sheet is pre-conditioned to lay flat and remain stable during and after installation. Application guidelines are provided every 2" across the sheet to aid the roofer in keeping asphalt shingles aligned. May be used as an eave protector on sloped roofing or as a complete high performance underlayment beneath heavy roofing such as tile or metal.