I have been doing home improvement for years and I think I have a good idea on what causes the black soil strips on carpet at carpet edge where it meets the wall.
I just wanted to see if this may be correct.
A lot of builders skip on materials due to costs and also due to the customer not knowing to ask (construction process)or not knowing what their builder is doing.
The area I am talking about is exterior walls. A lot of homes do not have a lot of wood on the exterior walls, builders use insulation then put the siding up.
Can this lack of solid wall area cause a major spike in air travel coming in through walls and escaping into house at wall/floor edge? Thus causing build up of dust, soil and more in the carpet area at wall edge.
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