Weather proofing OSB tiny home

I'm thinking of wrapping the exterior of my house (currently OSB plywood) with a mositure proof membrane to buy me some time to clad it. How long do you think that will give me? I will be putting sheet metal on the roof as well. I don't have the time or money to clad it yet so I'm keeping it inside a cow barn. The cows are cramped because the house is taking up half of their space, so I'd prefer to get it out. I should also mention that I'm in Ireland on an exposed site on a hill - so lots of rain and wind.

I have used mistinted paint as a temporary water shedding but vapor permeable coating. But that had a large overhang on it. My concern would be shedding bulk water but allowing any that leaked past to dry back out, which typically means something permeable to water vapor or installed with an airspace/ gaps. If the structure doesn't have a real roof yet, I wouldn't personally put it outside.

I think I would cover it in "tar paper" underlayment.
Not very natural, but your already using OSB.
Its rated for a certain amount of exposure,and its very cheap.
When you are ready to sheath and roof, it will already be in place.

Is Tyvek or something similar not commonly used over there?

I hope you mean it will be getting a metal roof when itngoes outside.. if so, I would expect well anchored tyvek or similar to be just fine at keeping it dry. Much better IMO than tar paper for longevity and effectiveness.

It is rated for limited peroids of UV/weather exposure during construction... but I have a north facing, well shaded, wall that has had some exposed for 3+ years without issue.

I like to use a very minimal number of plastic cap nails, far less than the standard calls for; then I immediately screw vertical strips of rot resistant wood over top. These provide the air gap for the rainscreen, once steel panels are installed over top.

Siobhan Lavelle wrote:I'm thinking of wrapping the exterior of my house (currently OSB plywood) with a mositure proof membrane to buy me some time to clad it.

I built my rather large house myself, with only the help of the 75 year old neighbor who pushed me along every day.  We fortunately got the metal roof completed late November before the snow began to fall. I wrapped the exterior walls with the generic version of Tyvek house wrap and it kept the OSB dry throughout the winter and spring until I was able to afford and install the siding.  It will last 6 months without a problem, just staple it well and tape all seems, I used Gorilla tape.

Being a Tiny House you can probably cut one piece and with a helper you can wrap all the way around and overlap the front so you only have one seem.