Fire starter! Insulate upstairs.

[GalliMattias]

Throwing in a firebrand. I've read many threads on the subject, but years go by and opinions and knowledge change.

Going to build new. 1.5 floors with a fully insulated upper floor. Wood fiber and vapor barrier in walls and roof (sloped roof). I haven't received the truss drawings yet, so I don't know how thick insulation I can use. Need some input on:

1. Air gap between roof sheathing and insulation? Or wood fiber directly against the outer roof?
2. Eave ventilation or not?
3. Regular roof felt or diffusion-open?
4. Ventilation at the ridge? Mold stoppers?

How would you have done it based on my conditions and choice of insulation/vapor barrier? Which combination do you think is the safest?

It feels like my QA, engineer, and carpenter have slightly different opinions on the best way to do it...😅

 

[fribygg]

Haven't received the roof truss drawings yet, so I don't know how thick insulation I can use.

I wouldn't let the choice of timber in the truss decide this but rather make it thicker so I get at least 400mm.

 

[GalliMattias]

Absolutely! Included it in case anyone thinks it matters for my thoughts. 😊👍

 

[fribygg]

Absolutely! Included it in case someone thinks it matters for my thoughts. 😊👍

How much are you planning to insulate?

 

[GalliMattias]

How much are you planning to insulate?

At least 400 mm, preferably 500 if possible.