Quote:
Originally Posted by Fourbtgait
I was simply curious if any one had for the fact pointed out before that the true R value is below what manufactures state.
As pointed out, “low cost” trailers like I own probably don’t vent roofs. True, I learned something there. Namely there is such a thing as roof vents for trailers, found them with google.
Problem with them is, are you really venting the roof? Without edge venting you have to increase the number of square inches of vent per square foot of roof area if you truly want to lower the trapped heat and moisture vapor in the roof system. But that square inch of venting would need increased because the screen used in vents technically reduces that vents capacity. To technical? Not really. One square foot of vent covered with 1/4” hardware cloth is only .75 square foot now. Decrease screen size, it drops even more.
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Few have pointed out that these manufacturers exaggerate just about everything about a RV. I've never seen once insulation being anywhere as dense as house insulation. And the foam board used is rated like blue board even though is the cheap styrofoam. Add some reflectix to that overated stuffing and you get R40+ as they say. R18 for the non dense stuff then another R20+ for something actually rated at 1.1.
The venting, well I guess people misunderstand why vents are
used , how they work to release excess hot air, lessen/prevent ice jams etc. And you have to have a lower inlet to go with the higher outlet, OOPS, doesn't have one.
Go ahead and stuff the attic of the RV, it'll only be better. If I could easily get into mine, it wasn't new, I'd do the same thing because that's where and RV biggest loss area is.