What does this mean?

[Carrerahill]

On my building warrant drawings, with regard to the timber frame it says, "... consisting of Tyvek Reflex and 2.0mm cavity breather membrane...".

 

What does that actually mean? To me I would just get a roll of suitable house wrap and attach it according spec - what gets me is the "and" and what does the 2.0mm refer to? rather than a dimension is this a typo and it was mean to be 2,000mm²/m or something... anyway confused and I cannot ask the guy who wrote it now. 

 

So, with the timber frame started at the weekend I will need a roll of something suitable this week - I know you can pay all sorts of prices for these, I don't want cheap but I want reasonable, I don't know that spending £400 on a roll of DuPont for example is worth it (well maybe it is) so what you guys have found to be good I'd be interested in hearing about - also, if I am buying a roll, as it is only an extension it would be good if it was one of those wall & roof membranes then I can use it all over.

 

Thanks

[Temp]

Could it mean Tyvek Reflex in the roof and a 2mm (0.2mm?) thick membrane in the walls?

Edited February 25, 2019 by Temp