6. Cold Bridging Accounts for 30% of Heat Loss!
Energy efficiency and u-values are important, but so is thermal efficiency!
A good u-value will not compensate for a poor quality, leaky construction.
And what self-builders often don’t realise is that thermal bridging alone can account for up to 30% of heat loss a well-insulated, airtight home.
The difference is massive!
So what exactly is ‘Thermal Bridging’?
Thermal bridges or ‘cold bridges’ are caused by breaks in the insulation layer.
Essentially, this happens when the cold outer leaf touches the warm inner leaf of the build.
Consider a block build for example..
The cold from the foundation rises to the walls above.
These walls surround your rooms – both internal and external.
And have you ever touched a block wall or lay with your head against one?
It radiates cold.. right?
So how can it be energy efficient?
Simple answer is – it’s not!
Not only do thermal bridges account for up to 30% of heat loss…
They can also result in the build-up of moisture, causing condensation and damp.
Yes – that’s why you’ll sometimes see those wet looking patches on the external walls of a block house, especially in the winter!
I’m sure you’ll agree, this isn’t something you’d expect from a newly built home?
But with timber frame..
The internal stud walls are packed full of insulation.
This insulation sits above the VAC pressure treated timber soleplate.
There’s a DPC layer underneath this to prevent rising damp/moisture..
And the insulation layer also works to force the cold back down so that it can’t reach your internal walls.
In the unlikely case that it does..
Your internal insulation will prevent thermal bridging through the timber studs!
This wall detail is essentially bulletproof (and we’re not just bias!).
So what are the takings from this..
If you focus on airtightness and thermal bridging, you’ll significantly lessen the energy demands of your build.
In turn, you’ll drastically reduce your heating costs!
So the obvious advice here would be to use a construction method that offers:
- A low u-value
- Excellent airtightness and;
- Minimal cold / thermal bridging.
And what construction method is that?
You guessed it.. timber frame!