My flat garage roof has been leaking and lack of funds means I'm having to tarp it. I have a load of old bricks so I was thinking of loose-laying a couple of courses down the centre then putting the tarp over thus forming a tent. The idea is that the tarp will last longer as any rainwater eventually leaking through will run down the underside of it rather than soak into the roof and any moisture from the roof if it does get a little damp in places will condense on the underside of the tarp and likewise run off down the undersides of the tarp. Or is this not worth the bother and I should just lay the tarp flat and keep replacing it until I can afford a proper roofing material installation?