Hello!
It's time to replace the roof on our house from the late '60s. It's a single-story house with a basement from the late '60s, roof pitch around 15°. Currently, there are tiles of a slightly thinner kind than what you usually see today. The base is just thin wooden boards.
We want to switch to classic tongue and groove, felt, and new tiles. What I'm concerned about is the increase in weight. Today's tiles are heavier than the ones we have, plus some addition from the tongue and felt, but perhaps that can be disregarded. But let's say we almost double the weight even though that's an overestimate. I'm not worried about the trusses; they will hold. But all the exterior walls in this house are 90-studs. It's a modular house from Myresjö, dating from 1969.
The neighbor with the same kind of house has replaced theirs and it hasn't collapsed yet

. Is my concern unfounded?