Tarp over an RV? Experiences and ideas?

[LowePro]

Does anyone have experience securing a large tarp (silver or white) over a camper-trailer? I was thinking about draping the tarp over the roof and securing with cargo straps through the grommets. Fastening it will be a challenge in the wind, for sure.

My main question is: Will this be effective at keeping out some heat? Or would the tarp act as a blanket and make it even hotter in the camper? Looking for people with direct experience, not hypotheses (I have plenty of those!). Thanks!

[Captain Goddammit]

It works well if you elevate it a foot or two above your roof - that's the key. Not so much if you lay it in direct contact.
I put grommets every foot around the perimeter in mine to tie it down, or to a metal pole along the edge which I then use a larger rope to secure. Spreading the attachment load evenly is crucial, if a strong wind storm hits it can easily tear your tarp from it's original few grommets.

Your refrigerator needs a little ventilation anyway if you are going to run it on propane. You don't want a tarp lying right on the roof vent for it with no air space.

[FIGJAM]