The Thermal Bridge Problem: Joining New Extensions to Old Homes Seamlessly
For homeowners worried that a new extension will create cold spots and heat loss where it meets their older home.
Meet The Pereiras
The Pereira family are adding a large rear extension to their 1930s semi. They've heard horror stories from neighbours about new extensions that stay warm while the old part of the house gets colder than ever — with damp patches appearing right where new meets old.
What a Thermal Bridge Actually Is
A thermal bridge is any point where insulation is interrupted, letting heat escape (and cold or damp track in) far faster than through the surrounding wall. The junction between an old, poorly insulated wall and a new, highly insulated one is one of the riskiest spots in any extension if it isn't detailed properly.
What a Thermal Bridge Actually Is
A thermal bridge is any point where insulation is interrupted, letting heat escape (and cold or damp track in) far faster than through the surrounding wall. The junction between an old, poorly insulated wall and a new, highly insulated one is one of the riskiest spots in any extension if it isn't detailed properly.
Continuous Insulation Across the Junction
The fix is to wrap insulation around the junction itself — extending it back into the existing wall, floor, and roof for at least a metre or so — rather than simply butting the new insulated build-up against the old uninsulated one and hoping for the best.
Continuous Insulation Across the Junction
The fix is to wrap insulation around the junction itself — extending it back into the existing wall, floor, and roof for at least a metre or so — rather than simply butting the new insulated build-up against the old uninsulated one and hoping for the best.
The Architect's Value
An architect details every junction between old and new construction on paper before building starts, identifying exactly where insulation needs to be extended, lapped, or upgraded so the whole house performs as one continuous, well-insulated envelope.