On Thursday, June 26, 2014 7:21:26 AM UTC-4, dadiOH wrote:
"Julie Bove" wrote in message





Well... Long story short, whoever built this building just slapped the

siding up over the 2 x 4's which is likely why it is rotting. Daughter

said she thought there should be Tyvek up underneath. My mom thought tar

paper. I looked online and it said specifically for a shed which is

basically what this is, to use house wrap. Not sure what house wrap is.



Tyvec is house wrap.



So my question is... How bad is it not to have anything underneath? And

what (if anything) should be underneath?



Tyvec et al is to minimize air intrusion/flow...to make a house more air

tight. It's presence or lack of same has nothing to do with siding or

sheathing rotting. However, its presence may help keep the internal

structure - the studs - from rotting by keeping water away from them.



I can think of no reason why you would need house wrap (or tar paper) on a

shed/storage building.


Seems you cited a reason, ie to keep any water that gets past
the siding from rotting the studs. And if water gets inside the
wall cavity, it's likely to remain there longer, possibly rotting
the siding from the inside. With Tyvek, any that get in doesn't
go far, it runs down and out.