We do however need to be careful with older buildings
They were made to breathe and need to
heres a quick Google on that
’ older buildings frequently suffer from these upgrades ( double glazing, roof insulation and sealing chimneys ) when installed incorrectly.
Traditional properties were designed to "breathe" using natural ventilation to manage moisture. Sealing them up with modern insulation or double glazing can trap moisture, leading to severe condensation, timber decay, and black mold.
The Problem with Specific Upgrades
Insulating Chimneys: Older homes rely on open flues and fireplaces for background ventilation. Sealing or capping them completely—without adding alternative background ventilation—shuts off a primary exhaust route for household moisture.
Too Much in the Roof (Over-insulating): Pushing excessive amounts of insulation into the eaves of a pitched roof can block essential cross-ventilation. Warm, moist air from below then condenses on cold roof timbers, leading to wet rot, dry rot, and mold. Additionally, using impermeable materials (like standard foam) rather than breathable options (like sheep's wool) traps moisture within the roof fabric.
Double Glazing: Fitting airtight double glazing stops the natural draughts that older, loose-fitting windows provided. This rapidly spikes internal humidity, often pushing moisture into the walls instead, where it can cause damage.
How to Prevent Issues
To safely upgrade an older building without causing structural damage, experts recommend a "whole-house" approach.
Balance Insulation with Ventilation: If you insulate heavily in the roof or block chimneys, you must install compensating ventilation, such as humidity-controlled extractor fans in kitchens/bathrooms or passive air vents.
Use Breathable Materials: Avoid rigid foam or petrochemical insulations in favor of moisture-buffering, breathable materials like wood fibre or sheep's wool.
Opt for Secondary Glazing: Instead of completely ripping out historic single-glazed windows, consider adding Secondary Glazing (such as discreet magnetic or fitted glass panels on the inside), which reduce heat loss while allowing the original windows to breathe.
For further advice tailored to older or heritage properties, refer to the detailed retrofit and energy efficiency guidelines provided by Historic England or the Society for the Protection of Ancient Buildings (SPAB).’
Just a thought for future renovators
SPAB offer excellent advice btw