Timberframe Wall Improvement?

[JOE187]

In 2011 I built a 2.5 storey timber frame house with render board on lower sections and wood cladding on upper levels,

Final uvalue 0.17 and air test of 0.9

Sound reduction is very good.

 

Wall make up from outside was.

 

12.5mm render board with parex top coat.

25mm cavity.

Housewrap taped  at joints.

50mm Rockwool Duorock

11mm OSB nailed and glued

145x45 studs filled with rockwool flexi

Reflective airguard stapled and taped

25mm service cavity.

12.5mm  Board skim finish  

 

   I had to do alteration to boiler flue at weekend and inside of wall looks good!

  I have another self build to start in near future and would like to improve/ Simplify? the wall build up so looking for ideas  and thoughts for improvements?

 

                                              

[redtop]

we used propassive OSB on the inside which removes one layer.  Also used the solid woodfibre boards on the outside  (140mm) which contributes (how much I don't know...) to the wall stiffness, gives it mass as well as insulation, not meant to need to wrap that with vapour control layer but we did.  Only issue so far, for a self builder, is the woodfibre boards are bloody heavy to handle on your own at height on the upper walls!  Ive had to resort to shoving them out through the window openings and onto the scaffolding.  No way in a million years I could get up ladders with them.  Hoist would work but that's a lot of time.

 

So woodfibre:- no problems with skin irritation, bit messy to cut cos it clogs the saw loads and very heavy to lug around on your own. prob takes longer to wrap house with it than it took to build the timber frame.

[Iceverge]

Hi Joe,

 

Those pictures look excellent. A perfectly continuous gap free insulation layer.

 

Are you framing on site or purchasing a kit?

What are your target U values? 

 

For a kit build an MBC 300mm twinwall or similar is a very elegant option as long as care is taken at the window+door openings. 

 

For a stick build your options are endless but something like @ProDave with rendered woodfiber as your weathering layer might save on the complexity. As with your rock wool duo, any external insulation does an excellent job of managing bridging at openings.

 

A wider, mineral wool insulated service cavity can be a cheap way of improving u-value also. 

 

[JOE187]

 Yes I would frame on site and look for around 0.15  u value!

  Have looked at wood fibre previously but local rendered examples did not look so good when a few years old.

 Went with rockwool as you can order by the pallet and just order right amount of packets to complete, off cuts can be put in internal walls.

 No extra transport costs or exchange rate hikes.