Sequoia Property Care

19/11/2025

A Serious Warning About Modern Insulations in Cornish Granite and Other Heritage Buildings

Modern insulation systems are often marketed as suitable for older homes, yet many are entirely inappropriate for traditional Cornish granite buildings and other solid wall heritage structures. These buildings manage moisture through their mass and their ability to absorb and release water gradually. When modern insulation is added without understanding this behaviour, significant hidden moisture and mould problems follow.

Granite walls are cold, dense and moisture holding. When insulation is installed without correct vapour control and without the guidance set out in BS 5250 and PAS 2035, warm indoor moisture is driven into the colder stone where it condenses inside the wall. This form of interstitial condensation is rarely visible until damage is already advanced.

A common misunderstanding involves materials described as vapour open. Vapour openness simply means water vapour can pass through the material. It does not mean the material is safe for heritage walls. Many modern insulations are not capillary active, which means they cannot move liquid moisture safely towards a ventilated surface. Many are hydrophilic, meaning they absorb and hold moisture within the insulation layer. When this moisture sits against cold granite or other traditional masonry, it becomes trapped. The dew point moves into the structure and hidden mould and decay soon follow.

Internal finishes begin to fail. Timber lintels weaken. Mould grows inside the structure long before any visible signs appear.

Sequoia Property Care’s Advice
Heritage buildings require a moisture aware approach. Any insulation decision must include vapour resistance analysis, dew point calculations and ventilation assessment in accordance with BS 5250 and PAS 2035. Materials must be chosen for their moisture behaviour, not their marketing description.

If you are concerned about hidden mould or the suitability of existing insulation, Sequoia Property Care can carry out a detailed moisture assessment and identify any risks within the building fabric.

19/11/2025

We’re often asked about ECO4 grants — here’s what most people aren’t being told.

A recent report found that 98% of ECO4 external wall insulation projects are vulnerable to damp and mould issues. 98%!

Why does this matter?
Because when insulation is rushed or poorly specified, it traps moisture inside the building fabric, creating perfect conditions for mould to grow behind the insulation and spread into living spaces.

Many of these jobs are carried out by “here today, gone tomorrow” companies who chase the grant money, finish quickly, and vanish long before the mould problems show up.

This can lead to:
• Hidden mould inside the walls
• Condensation behind the insulation system
• Damp patches that keep returning
• Health risks for occupants
• Costly remedial work for homeowners

Grants can be beneficial — but mould risk must be properly assessed. If ventilation, moisture pathways and building fabric behaviour aren’t understood, the insulation can do far more harm than good.

If you’re considering ECO4, get independent, fabric-first mould and moisture advice before any work starts. It’s the safest way to protect your home and avoid long-term issues.

Wall insulation installed under two separate schemes was supposed to keep residents warm and dry, but instead left some homes damp and mouldy

15/11/2025

Mould starts when moisture can’t escape – and this image shows exactly why.

People often say “old walls need to breathe”… but walls don’t breathe. They evaporate. And when a home can’t evaporate moisture fast enough, mould takes over.

In the photo, the condensation on the door is extreme. Surfaces this wet stay damp for hours, creating ideal conditions for mould to grow and spread. This isn’t just a little moisture – it’s a clear sign the property can’t get rid of humidity.

Many Cornish homes have thick, solid walls that hold a lot of moisture and dry very slowly. When ventilation is poor, everyday activities like cooking, showering and drying clothes push humidity higher than the building can handle. Moisture stays trapped, and mould follows.

Breathable materials like lime help, but only when combined with good ventilation and controlled humidity. Without airflow, moisture simply remains inside the property, feeding mould growth.

So old walls aren’t “breathing.”
They’re evaporating.
And when evaporation slows, mould thrives.

At Sequoia Property Care, we find the real causes of mould and restore healthier indoor conditions. If your home is showing condensation like this, you’re already at high risk – and we’re here to help.

20/10/2025

Understanding Condensation in Cornish Homes
Condensation is one of the most common issues in Cornish homes, particularly in traditional cottages. It occurs when warm, moisture-rich air meets a cold surface, causing the air to cool and release water vapour as droplets.

When this image was taken in Truro, the relative humidity was 91%. That means that at the air temperature at the time, it was holding 91% of the moisture it could hold before releasing it as water. At 100%, condensation appears.

Relative humidity is directly affected by temperature. As air cools near cold surfaces like glass, walls, or floors, its capacity to hold moisture decreases, and condensation forms. On cold, dry days, this is far less noticeable because the air contains less moisture overall.

In Cornwall, the lowest average monthly relative humidity is still around 81%, which means the air is naturally moisture-rich throughout the year. This is why condensation is such a frequent problem in Cornish homes and cottages.

To reduce condensation, the key is balance. Effective background ventilation and continuous running fans in bathrooms and kitchens help remove moisture from the air before it settles on cold surfaces. Consistent heating also plays an important role. When the air and walls are kept at a steady temperature, the risk of condensation drops significantly.

Opening windows for short periods may seem helpful, but it often causes more harm than good. The rapid heat loss cools surfaces, making condensation and mould more likely to form once the windows are closed again.

The most effective approach in Cornish properties is to maintain steady heat levels and ensure proper mechanical ventilation. Continuous fans, background vents, and gentle airflow are far better at controlling humidity and preventing condensation-related issues.

06/10/2025

When PIV Systems Can Contribute to Mould

Positive Input Ventilation (PIV) systems work on a principle called dilution. They draw air from outside, filter it, and push it into the property to dilute stale, humid indoor air.

However, this week outdoor relative humidity across Cornwall and Devon has been between 80 and 90 percent. In these conditions, the air being drawn in already contains a high level of moisture. When that moist air is introduced into home, it can raise the internal relative humidity instead of lowering it.

This can result in surface condensation, especially on cold walls, window reveals, and corners where air movement is limited. Over time, these damp areas can support mould growth, even in homes fitted with ventilation systems.

In short, PIV systems only provide any form of positive benefit when the outdoor air is drier than the air inside. When outdoor humidity is high, the system continues to move air, but the dilution process no longer provides a drying effect.

At Sequoia Property Care, we carry out mould and ventilation surveys to check whether systems like PIV are helping or hindering your building’s moisture balance.

If you are noticing mould despite having a PIV system installed, we can help identify the cause and guide you to the right solution.

www.sequoiapropertycare.co.uk

24/09/2025

Mould in the Loft - Investigation
During a recent survey, we found mould growing on the underside of “breathable” felt in the loft.

The absolute humidity levels told the story:
- Ground floor air held 25% more moisture than outside
- First floor air was a shocking 37% higher!

The cause? Inadequate ventilation within the living space, combined with a roof build-up that had no airflow at the eaves or ridge.

Remember: breathable felt is not ventilation. Without proper air movement, all that extra indoor moisture condenses on the felt — creating the perfect conditions for mould.

Left untreated, this can spread spores through the home.

At Sequoia Property Care, we don’t just remove mould — we identify and fix the cause with the right balance of ventilation and insulation.

If you’ve noticed black mould in your loft, get in touch today for a professional survey.

08/09/2025

Live Mould Risk Assessments with Thermal Imaging
At Sequoia Property Care, we go beyond the basics when it comes to identifying damp and mould problems. Our advanced thermal imaging equipment allows us to carry out live mould risk assessments on site, giving you clear, immediate answers.

Unlike standard thermal imaging cameras that only capture surface temperature, our equipment also measures humidity at the surface of the material. This means we can quickly identify areas where mould is most likely to grow, even before it becomes visible!

By combining temperature and humidity data, we can see where condensation is forming, pinpoint thermal bridges, and highlight hidden risks that often go unnoticed. And because the results are available in real time, we can carry out further investigations straight away while on site.

This proactive approach helps ensure:
- The true cause of mould is identified — not just the symptoms.
- Remedial action can be planned with confidence.
- Issues are resolved effectively, preventing recurrence.

If your home or property is suffering from damp, condensation, or mould, a thermal imaging survey is one of the most effective first steps you can take.

Call Sequoia Property Care today to book your mould risk assessment and take the first step towards a healthier, mould-free home.

17/08/2025

Why Internal Wall Insulation Can Be a Risk in Heritage Homes

At Sequoia Property Care, we’re seeing more cases where ECO4 grant-funded insulation schemes are causing serious problems in older buildings, particularly traditional stone, cob, and solid-wall properties across Cornwall.

Internal wall insulation (IWI) is often installed quickly to meet government targets, but in heritage homes it can be highly damaging:

Traps Moisture – Historic walls are designed to “breathe.” When covered with insulation boards or vapour barriers, moisture can no longer escape, building up inside the structure.

Mould Growth – Condensation often appears on cold bridges (around floors, ceilings, and window reveals). Once mould takes hold, it’s not only unsightly but a real health risk.

Decay of Original Fabric – Damp trapped in stone, cob, or timber causes salts, frost damage, and rot – sometimes hidden until it’s too late.

False Promises of Efficiency – While grant installers promise lower bills, poorly specified insulation can make the property harder to heat and more expensive to repair.

ECO4 companies are under pressure to install fast and cheap. Too often, there’s no proper survey, no moisture testing, and no consideration of the building’s age or construction. The result? Homeowners left with damp, mould, and even structural damage – and no support once the grant money is paid out.

At Sequoia, we take a very different approach. Every property we work on is surveyed properly first – using moisture diagnostics, ventilation assessments, and an understanding of how heritage buildings perform. Our aim is always to balance comfort and efficiency with long-term preservation.

If you’re being offered ECO4 internal insulation, speak to us before you sign anything. We can advise on safer alternatives, ventilation improvements, and energy upgrades that won’t compromise your home.

👉 Protect your property. Get the right advice.

Sequoia Property Care – Conservation-led building repair and retrofit across Cornwall.

16/07/2025

Fogging And mould Washes Are Not Remediation
Don’t be misled by quick fixes.

Mould is often "treated" with fogging or surface sprays and sold as remediation. It’s not. In many cases, the chemicals used are more harmful than the mould itself.

Proper mould remediation means addressing the cause — not masking the symptoms. That means:

- Identifying the moisture source
- Fixing ventilation or insulation issues
- Repairing defects
- Treating mould safely and thoroughly

Fogging has a role — but only after remediation, never instead of it. If you're being sold fogging as the solution, you're not being sold remediation.

www.sequoiapropertycare.co.uk

12/07/2025

Why Mould Testing Matters.
You can’t manage what you haven’t measured.

Mould testing isn’t just about confirming what you can already see, it’s about understanding the type, spread, and risk level of the problem.
Here’s why it’s worth doing:

1. Identify hidden mould
Mould often grows in cavities, behind walls, or under floors. Testing helps uncover what’s not visible.

2. Know what you're dealing with
Different mould types produce different toxins. Some are harmless. Some are a serious health risk.

3. Protect health
Testing helps assess potential health impacts, especially important for vulnerable occupants with asthma, allergies, or respiratory issues.

4. Target the solution
A proper diagnosis leads to a proper plan. No guesswork. No overspending.

5. Prove the outcome
Post-remediation testing provides proof the job’s been done right. Ideal for landlords, tenants, and insurers.

If you’re guessing, you’re risking.

Test first. Treat properly. Live healthier.

www.sequoiapropertycare.co.uk

11/07/2025

Heritage Damp Surveys
Poor surveying practices often lead to costly misdiagnosis.

This case was incorrectly labelled as rising damp.
But our gravimetric testing and salt analysis confirmed otherwise.
The real issue? Penetrating damp from a leaking gutter and failed pointing, not capillary rise.

When it comes to heritage buildings, assumptions can do real damage. We take a scientific, conservation-led approach to diagnosis and repair.

- Gravimetric moisture testing
- Salt analysis
- Detailed reporting
- Conservation-aware damp solutions

11/07/2025

Flat Roof Repairs
Sadly, this roof is well beyond its serviceable life.
Water ingress has caused extensive damage to the deck, and the insulation is completely saturated.

Flat roofs should be inspected regularly, especially if they're more than 15 years old. Catching issues early can save you thousands.

Sequoia Property Care offers detailed roof condition reports and honest advice.
If your flat roof is leaking or showing signs of age, get in touch today.

- Professional repairs
- Full replacements
- Insulation upgrades
- Drone surveys and reports