Just what you've been looking for, a realistic AGED Tarpaper sheet.
These tarpaper sheets are available in seven (7) different colors and are laminated to a newsprint backer sheet to give them body.
Because they represent aged tarpaper, there may be occasional holes, small wrinkles, etc.
As these are made through the lamination of a fine tissue sheet to a thin newsprint some blemishes creep in. All sheets are larger than dimensions give so there is ample material.
Each packet includes four (4) sheets that each measure approximately 5" x 5" and are easily cut and applied to your sub-roofing.
Also available are laser pre-cut strips - your choice of 36", 42", or 48" wide strips for your selected scale.
If you desire a weathered appearance to the Tarpaper:
For the Black Tarpaper a light over-spray of Gray Automotive Primer. Keep the coating just a fine mist, do not over spray the tarpaper sheet.
For the Gray Tarpaper a light over-spray of a Flat Black will work. Keep the coating just a fine mist, do not over spray the tarpaper sheet.
For un-cut sheets, cut the sheet to a 3 foot width in your chosen scale. Use a sharp X-Acto blade and a very low angle on the blade. Use a steel rule as a guide held down firmly on the tarpaper sheet.
You can turn the sheets face down and draw pencil lines on the newsprint backer for easier cutting. Cutting the sheet in the face down position can also lessen tearing.
Use Tacky Glue or 3M #465 Transfer Tape to apply your strips of Tarpaper to the sub-roof of your model. Carefully smooth the sheets down and overlap successive sheets a scale 3" as you move up the roof with each row of Tarpaper. Seams can be highlighted with Gloss Black Paint to simulate fresh tar sealant.
Weathering can be done with pastel chalks and fixative sprays. A light application of a wire brush or scratch brush can be used to feather edges or show worn spots.