1. Help with Ubakus 2. Outside insulation redux

[Garald]

Hi,

 

I'm trying to model my wall in Ubakus, and I'm stuck because I can't find one of the materials. (Long story short: the wall is already insulated on the inside, with a mixture of traditional and reflective materials; I am considering insulating it on the outside.)

 

1. This is the wall as it stands now:

 

From inside to outside (and top to bottom, within the diagram):

 

BA18 plaster layer (18mm)

45mm BioFib trio

unventilated air layer (R=0.53, supposedly)

ATI PRO MULTI HPV (reflecting insulation) (40mm)

ventilated air layer

masonry wall of unknown composition and thickness, from the 1930s (well, I suppose I could estimate its thickness, but I have no idea of how to get an accurate measurement).

 

The problem is that, while BioFib Trio is in Ubakus's database, ATI PRO MULTI HPV is not. Is there a close substitute?

 

2. I'm starting to get quotes from different artisans for the possible outside insulation. (My goal is to get an R of about 4 on the outside alone - in part because that way I might be able to get subsidies (finally)).

Here are some options, all of which cost more than I expected (for a wall of about 72m^2 excluding windows):

 

Business 1: 17621eur for rockwool (16 cm, R=4.55)

Business 2: 14432eur for expanded polystyrene (14 cm , R=4.4)

I should have an estimate from Business 3 soon.

 

Are prices in the UK similar? I can provide some links with pictures so that people can tell me whether what these folks do looks like quality installations.

 

(Also, is rock wool really eco-friendlier than polystyrene? What advantages that it pose, other than being fire-proof? Is polystyrene on the outside a hazard?)

Edited June 13 by Garald