Thermal Bridging

[caz440]

Hi,

I am proposing to build a house with timber cladding directly onto the timber frame studwork which will be insulated and plasterboard on the internal face. I have spoken to a building engineer and he thinks that because the studwork doesn't have an OSB sheathing then the moisture wont "wick" into the structure. However, will this cause a problem with regards to thermal bridging?

 

[jeds]

Yes you will have a thermal bridge but that, and any condensation risk, should be calculated in the U-value.

 

[^woody^]

If you don't sheath the frame then it will not have any racking resistance (ie will twist or fold). This will be your main problem

With regards to a thermal bridge, the OSB (or lack of) wont make any difference at all. Think about it, its just another bit of timber between the cladding and the frame - whether its there or not, will not have any impact on the thermal transfer from the cladding to the frame.

If you insulate the internal face, then there will be no thermal bridge as the insulation is the barrier. It would be better with some insulation within the frame too though.