How Emergency Roof Tarping Works
A roof tarp only works if water cannot get under its top edge. We use a heavy-duty reinforced tarp sized to run from below the damaged area, up and over the ridge, and down the other side, so water sheds over the tarp rather than behind it.
The tarp edges are rolled around wood battens, and the battens are fastened where they do the least harm, at the ridge, into areas already damaged, or into spots that will be reshingled anyway. Nailing a tarp straight through sound shingles creates dozens of new holes, which is the most common mistake we see on do-it-yourself and storm-chaser tarps.
On exposed deck we often apply self-adhered membrane before the tarp goes on, which gives a second layer of protection if wind works the tarp loose. A properly anchored emergency roof tarp is meant to hold for weeks while the permanent repair is scheduled, not for a whole season.