the tarp technique is common out here. the key thing is that the higher end of the tarp needs to be arranged such that much rain doesn't seep under it; i.e., drape it over the peak of the roof and weigh it down there, or nail it to the side of the building under the eaves where it's protected from the wet. draping sides of the tarp over the side of the roof (weighted) where possible is also good.
if you want to be really thorough, i don't see any reason why you couldn't assemble a number of tarps into one mega-tarp that covers the entire roof, overlapping each other enough to prevent leakage. i'm thinking with the help of a stud finder you might even be able to nail it in place and then use some sort of tape or sealant to cover the nails.
do you know anyone who sails? i bet sailors know all sorts of useful things about keeping things dry.
(no subject)
if you want to be really thorough, i don't see any reason why you couldn't assemble a number of tarps into one mega-tarp that covers the entire roof, overlapping each other enough to prevent leakage. i'm thinking with the help of a stud finder you might even be able to nail it in place and then use some sort of tape or sealant to cover the nails.
do you know anyone who sails? i bet sailors know all sorts of useful things about keeping things dry.