Technical Specifications
Here you can read in more detail about the technical details of the windows we produce and the materials we use within our repair and upgrade services.
Heritage Glazing
Our conservation-approved toughened Heritage Double Glazing is just 16mm thick, but with superior Krypton gas (not standard argon) in the 8mm cavity, your windows perform exceptionally well while maintaining a traditional slender appearance.
- Slim profile, superior performance – At just 16mm thick, our units use Krypton gas (twice as dense as standard Argon) to achieve a centre-pane U-value of 1.2 W/m²K
- Authentic appearance – Black spacer bars replicate the shadow gap of traditional single glazing, maintaining the historic character of your windows
- Long lasting – Guaranteed against cavity failure for 10 years, and expected to last much longer. Toughened glass in both panes ensures durability.
Product: 16mm Heritage Double Glazing with 8mm Krypton-Filled Cavity, Black Warm-Edge Spacer Bar, Toughened, Low-E Coating
Values (the term used to measure thermal efficiency)
A U value is a measure of heat loss in a building element, therefore, it is the measurement of the whole window and not just the glass. It can also be referred to as an ‘overall heat transfer coefficient’ and measures how well parts of a building transfer heat. This means that the higher the U value the less efficient the thermal performance of the building element. A low U value usually indicates higher levels of insulation.
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Vacuum Glazing
We are accredited suppliers of LandVac Vacuum Glazing.
Upgrade to Vacuum Glazing for unrivalled heat and sound insulation, while keeping the windows looking completely original. Perfect for listed buildings and conservation areas where authentic appearance matters.
LandVac Enhance Vacuum Glazing delivers exceptional performance at just 8.4mm depth, making it virtually indistinguishable from traditional single glazing, especially when paired with white glazing tape.
_What you’ll notice:_
- Exceptional warmth – U-value of 0.4 W/m²K, outperforming triple glazing, and dramatically reducing heat loss and energy bills
- Remarkably quiet – 39 dB Weighted Sound Reduction Index, in line with mid-range (and much thicker) acoustic glazing
- Unrivalled Durability – With a 25-Year manufacturer’s guarantee, and a life expectancy far beyond that, LandVac Enhance represents a one-time upgrade
Product: LandVac Enhance S1.10 Vacuum Glazing, 8.38mm
Important: This glass features microspacers in the cavity, which are visible upon close inspection.
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Accoya timber
We are also approved suppliers and manufacturers of Accoya wood. Accoya turns everything you know about wood on its head. It is timber that has been modified via a process called ‘acetylation’, which increases its durability, enabling it to resist rot, defy the elements and stay strong and resilient for decades to come, without effecting its natural appearance.
The treated wood is thoroughly tested for dimensional stability, durability, paint retention and in-ground conditions, ensuring it achieves the optimal performance.
From a sustainability perspective, while other types of durable woods tend to be slower growing species, Accoya is made using fast growing, sustainably forested radiata pine.
Accoya offers outstanding durability, meaning it is long lasting and also easy to machine, sand and paint and its incredible dimensional stability means it will not swell or contract with temperature and humidity changes – which makes it ideal for windows and doors.
Great stability
Dimensional stability is the degree to which a material maintains its original dimensions when subjected to environmental changes. With Accoya, swelling and shrinkage is reduced by 75% or more, which means doors and windows will open effortlessly all year round.
Durable
Accoya offers the best level of durability possible in wood. Lasting 50 years above ground, and 25 years in ground or freshwater, it has Class 1 durability. This surpasses even teak. It forms an effective barrier to insect attack, being indigestible to microorganisms and insects and therefore more durable to wood-destroying fungi, and is virtually rot-proof.
Robustness
The process used on the timber increases the wood’s strength and hardness. Its high strength-to-weight ratio makes it suitable for even the most challenging applications.
Accoya works well with all known coatings systems. The wood is easy to coat as it requires less preparation and sanding that others. Its improved stability also means coatings last up to two times longer, which reduces the need for maintenance. And the less time spent maintaining the wood, means less money being spent on coatings and the less coating used during the life time of the wood.
Superior insulation
In comparison to other commonly used hardwood and softwood species, Accoya wood offers superior thermal insulation. This provides energy conservation advantages such as when used in applications including window frames and doors.
Attractiveness
The modification process does not compromise the wood’s natural beauty. It remains comparable in colour to the original source species, allowing for a natural look to be created in a property. Alternatively, it can easily be coated in a wide range of colour finishes.
Sustainable
Accoya is sourced from FSC® and other regionally certified woods, meaning it is a naturally renewable material. Only abundantly available, fast growing source species, such as Radiata pine, are used in its creation.
Environmentally-friendly
Accoya wood provides compelling environmental advantages over slow-growing hardwoods, woods treated with toxic chemicals and non-renewable carbon intensive materials such as plastics, metals and concrete.
The manufacturing process is also non-toxic and adds nothing to the wood that does not already naturally occur in it. It protects the environment from the harmful effects of common treatments and may be safely reused, recycled and incinerated.
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Sashcraft’s Advanced Sealing System
Cambridge Sashcraft’s patented Advanced Sealing System ensures optimum operational, acoustic and thermal efficiency on all period windows we work on.
The Sashcraft Advanced Sealing System is protected under UK Patent No. 2580028, and European Patent No. EP3670809.
Our in-house system utilises an optimal arrangement of Schlegel weather seals that are built into sash and casement windows to eliminate thermal and acoustic ingress.
Unlike brush draughtproofing systems which fail when brushes are exposed to moisture or paint, our sealing system is highly durable and effective, with our system benefitting from the following properties of Schlegel seals:
- Excellent memory – returns to original shape after compression
- Stability – low/no stretch gained by glass fibre internal cord or insert
- Easily compressed – low compression forces, unaffected by temperature variance
- Acoustics – outstanding acoustic performance – independently tested
- Thermal conductivity – unrivalled thermal performance – independently tested
- Paint and Stain Proof – properties unaffected by standard paints and stains
- Stabilised – unaffected by rot, fungi, UV light or ozone
- Patented – Schlegel has been innovating seals for over a century
- Temperatures – the widest operating range +70ºC to -65ºC
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Ironmongery
For sliding sash windows, we supply and fit new high-quality window accessories: brass/chrome pulley wheels, sash lifts and a lockable heritage fitch fastener – which has been approved as a Secured By Design Official Police Security Initiative.
For casement windows, we supply and fit high-quality fasteners and stays: solid brass or chrome as preferred with lockable options.