Cladding & insulation

Hi All,

I am trying to get a better understanding on external wall cladding installation and thermal insulation.

When an external cladding material (e.g. weather board) is directly nailed in to timber frames (which are wall wrapped), the nail will penetrate timber frames while piercing the wall wrap.

With the number of nails piercing the wall wrap (to hold cladding in place), can this somewhat decrease the wall wrap insulation/ protection ability, in preventing thermal loss and barrier against moisture etc? Is this something to be greatly concerned about? Or maybe the overall impact is negligible?

Thanks.

in my understanding
on a cladding wall the wall wrap is a secondary barrier to water penetration
the insulation is placed in the wall cavity between the studs
on a brick veneer the wall wrap reflects the heat into the cavity between the bricks and the wrap and acts as insulation

interesting scenario ! the cladding material and frame are bad conductor of heat...the impact due to nails into the frame should be negligible. overall the cladding will reduce (compared to brick) the insulation on that side as well.

Because we are using timber cladding, I've been reading about thermal bridging, so it made me think about this scenario.

look up r value brick veneer vs cladding
cladding 0.55 r value
brick veneer 0.51 r value

Hi aussieta, thanks for the info. Actually, my original question relates more to thermal bridging impact between timber frame and cladding. As the nail joining both materials acts as a bridge.

the nail goes into the timber, which is a reasonable insulator
as opposed to an aluminium framed window which thermally bridges the gap between inside and out

Although there will be some thermal bridging from the nails, the timber studs themselves are a bigger thermal bridging concern (assuming that you're insulating between the studs - timber is much better thermal conductor than insulation). The practical impact of this will depend on your circumstances, e.g. house size and orientation, climate zone, overall insulation strategy, etc.

If you want to avoid thermal bridging altogether, then you'll need to look at either using a different construction than timber frame (e.g. ICF, SIPS) or using an insulating external cladding instead of weatherboard (e.g. EPS). Again, some or all of these options may be overkill for you, depending upon your particular circumstances.

If you are so concerned about thermal bridging caused by studs themselves as well as nails, consider a layer of rigid boards insulation such as XPS or (better) PIR placed in front of the studs. Use composite nails instead of metallic ones to attach the boards to your studs. Place your cladding on top and attach it to the board with the similar composite nails.

The surface area of each nail head and impact (Conductance & Transfer) is negligible
wood is a poor conductor or energy
there is no need to prove this with science, math & FEM illustration/simulation
OT, Here is a simulation example for "Shaded & Unshaded Esky with drinks
which is used to predict beer temperature in an esky at the beach... BTW the beer temp difference in WA during summer is 2 deg.. LOL no need for an app. Common sense should tell you that you don't need a better esky design

Thanks all for your input.