Vapour-open mineral insulation for pre-1919 buildings. Your walls and floor can breathe while your home stays warm.
Pre-1919 buildings were designed to breathe. Lime mortar, solid brick and stone absorb and release moisture as part of a natural cycle. Seal that wall with modern insulation and you trap moisture inside the structure.
The consequences (interstitial condensation, accelerating fabric decay, mould) are invisible until serious damage is done. The UK's 5.9 million pre-1919 buildings need a better answer.
See the BreatheTherm solutionPIR boards create cold bridges and vapour barriers that cause moisture to condense inside the wall, invisibly damaging the historic fabric.
Wet walls conduct heat up to 3× faster than dry ones. Conventional insulation that causes dampness can actively worsen energy performance over time: the opposite of its intended purpose.
Bulky insulation systems alter window reveals and room proportions: the very features that define a Georgian or Victorian building. BreatheTherm achieves excellence in as little as 25mm.
BreatheTherm breathable insulation is specifically formulated for pre‑1919 and listed buildings. Our systems use natural vapour‑permeable materials (including perlite and aerogel) that maintain the balance your walls depend on.
Vapour‑permeable materials allow moisture to pass through rather than accumulate at the insulation boundary.
Our hygroscopic products absorb peak moisture and release it gradually. This helps smooth out humidity spikes inside the building and within the wall.
No interstitial condensation means no timber decay, masonry spalling, failed renders or mould growth.
Dry walls insulate better. As moisture balances, heat loss reduces and efficiency genuinely improves.
Our breathable systems help walls operate closer to their intended thermal performanceHover or tap any marker on the diagram to discover the material properties, thermal performance data, and guide pricing for each BreatheTherm component.
Or select a layer directly from the legend below.
Walls (select one to learn more)
Floor (select one to learn more)
RETROFIT WITHOUT REGRET
The cheapest insulation is not always the lowest cost option. In traditional buildings, moisture risk, failed detailing and fabric damage can turn a quick fix into an expensive problem.
| Conventional Insulation | BreatheTherm System | |
|---|---|---|
| Upfront cost | Lower | Moderate–higher |
| Moisture safety | Higher risk in solid wall building | Designed to manage moisture safely |
| Breathability | Typically sealed systems | Fully vapour-open |
| Listed building suitability | Often difficult to obtain consent | Typically more acceptable |
| Build-up thickness | Often requires thick layers | Slim, space-saving build-up |
| Long-term performance | Can degrade if damp develops | Stable, moisture resilient |
| Remedial risk | Risk of corrective works if issues arise | Significantly reduced risk |
| Property value impact | Risk of issues arising at survey | Long-term quality increases valuation |
| Installer complexity | Multiple systems and detailing required | Simple, integrated system |
Select your profile to access the right starting point. Each path is different but every outcome is the same: a better, healthier, more efficient building.
Future-proof your heritage building. Reduce energy bills and eliminate damp without compromising the character or fabric of the construction.
Specification-ready systems for the most sensitive buildings. Full technical support from design stage to site sign-off and LPA approval.
Join the approved installer network and tap into the UK's 5.9 million pre-1919 buildings waiting to be retrofitted properly. First in your area.
Every project is different. Every outcome is the same: a warmer, drier, healthier building that retains its heritage character for generations to come.
Breathable internal thermal upgrade to bare brick walls and a retained lath ceiling using PerliScratch, AeroBond, mesh, and PerliTherm improving surface warmth and reducing condensation risk while preserving historic fabric.
Internal wall insulation across 12 flats with hygrothermal monitoring installed throughout. Zero moisture failures recorded at 36-month post-completion review.
Solid stone walls, cob partitions and original lime plaster. Significant thermal improvement achieved while satisfying Historic England's strictest requirements.
The work was carried out quickly and with a minimum of disruption or mess... The wall now feels dry, and warmer to the touch than a similar, untreated stretch of wall. There are also no signs of discolouration or damp patches. We are considering having all our affected walls treated by BreatheTherm.
Struggling for many years with a continually damp wall in barn conversion with no damp course... BreatheTherm ‘does what it says on the tin’. It allows the moisture in the wall to pass through and wick – result has been a dry wall throughout recent downpours.
The whole BreatheTherm process has been far more straightforward and succesful than I could have imagined. I am absolutely thrilled with the result and would have no hesitation recommending BreatheTherm to anyone looking to improve the performance of a traditional property.
BreatheTherm was founded by two practitioners who, for decades, watched conventional insulation fail. But with that frustration they built something better.
Josh founded HF Limited in 2003, building a reputation across the Cotswolds for high-quality construction and period property restoration. Two decades of hands-on work in traditional buildings revealed the same problem time and again: modern insulation was failing the structures it was meant to protect. That conviction drove the creation of BreatheTherm — a technically rigorous answer to a problem the industry had largely ignored.
Greg joined Josh at HF Limited in 2007, becoming the technical backbone of the partnership. Together they launched HF Building in 2016, specialising in the conservation and retrofit of period properties. Greg's deep knowledge of heritage construction — and his frustration with products that damaged the buildings they were meant to improve — made BreatheTherm the next logical step.
Everything you need to know before your free assessment.
Still unsure? Call us on 01285 407088: we're always delighted to talk through the specifics of your project.
Book an assessmentSpeak to a heritage retrofit specialist. No obligation. Clear advice tailored to your building type, age, and any conservation requirements. We typically respond within one working day.
Future-proof your heritage home. Reduce energy bills and eliminate damp without compromising the character or fabric of your building.
Specification-ready systems for the most sensitive buildings. Full technical support from design stage to site sign-off and LPA approval.
Join the approved installer network and tap into the UK's 5.9 million pre-1919 buildings waiting to be retrofitted properly. First in your area.
A member of the team will call within one working day to arrange your free property assessment.
In the meantime, call us directly on 01285 407088.
Your Heritage Home,
Our specialists will visit your property, assess your wall construction, and recommend a system tailored to your building's age, type, and conservation status. No hard sell — just clear, honest advice.
Specification-ready.
Our technical pack includes full NBS clauses, hygrothermal modelling support, BIM objects, and a comprehensive conservation area approval record — everything needed for a smooth specification and LPA sign-off.
Join the Network.
We train your team, support your jobs, and connect you with a pipeline of homeowners, architects, and conservation officers who need exactly what you'll be able to offer. No other certified installer in your area.
