SashWise

Business Details

20 Years

experience

Trusted Sash Window Specialists in Twickenham

SashWise is a family-run business established in 2006, specialising in the restoration, repair, and replacement of timber sash and casement windows across West London. With over 25 years of combined experience, our team prioritises preserving architectural heritage while integrating modern efficiency. We use premium materials like FSC-certified Accoya timber and innovative solutions such as Fineo vacuum glazing to enhance energy efficiency and durability.

Our services include draught proofing, double glazing upgrades, and full window restoration, tailored to period and modern properties. Committed to sustainability, we partner with Ecologi to plant a tree per order and maintain a paperless, cloud-based workflow. Our local workshop in Twickenham ensures personalised service, combining traditional craftsmanship with contemporary performance to meet diverse client needs.

Services

Sash Window Replacement Draught Proofing Timber Window Restoration Double Glazing Upgrades Door Installation Rot Repair Fineo Vacuum Glazing Aluminium Window Supply Window Servicing Eco-Friendly Solutions

Details

Year established: 2006

Highlights and features

We have over 25 years of combined experience in timber sash window repair.
We operate a local workshop in Twickenham for efficient project management.
We use the highest quality materials, including sustainably sourced Accoya timber.
We charge 0% VAT on all draught proofing work.
We match original window designs to preserve period authenticity.

Associations and certifications

Forest Stewardship Council

What people say

Proactive and professional Delighted with the windows Faultless installation Polite and respectful Spotless workmanship

Website

Update Listing

Services

Sash Window Replacement

We craft and install custom timber sash windows that replicate original designs while incorporating modern double glazing. Our replacements enhance energy efficiency and security without compromising period aesthetics. Each window is tailored to match historical details, ensuring seamless integration with your property's character.

Draught Proofing

Our draught-proofing solutions eliminate cold air infiltration by fitting discreet seals, improving thermal comfort and reducing energy bills. This service extends window lifespan while maintaining visual appeal, using materials compatible with traditional timber frames for lasting performance.

Timber Window Restoration

We restore aged timber windows by repairing rot, replacing damaged components, and refinishing surfaces. Our sympathetic approach preserves historical integrity while upgrading functionality. Techniques include fine sanding, repainting with durable finishes, and installing modern hardware for smoother operation and enhanced security.

Fineo Vacuum Glazing

Fineo vacuum glazing provides high-performance insulation in ultra-thin units ideal for period properties. We integrate this technology into sash windows without altering original frames, achieving U-values as low as 0.7W/mK. This solution maintains heritage compliance while significantly improving thermal efficiency and noise reduction.

Aluminium Window Supply

We supply aluminium windows combining slim sightlines with thermal efficiency, suitable for heritage and contemporary properties. Our Alitherm ranges feature durable powder-coated finishes in RAL colours, offering low-maintenance solutions that meet modern building regulations without sacrificing aesthetic appeal or security standards.

People

Dan Johnston

Owner and Managing Director

Dan oversees SashWise's operations, combining hands-on expertise with strategic leadership. With over 17 years in the industry, he specialises in period window restoration and project management, ensuring every installation meets exacting standards while preserving architectural integrity.

Melissa

Office Manager

Melissa manages client relations, marketing, and administrative operations. Her organisational skills ensure smooth project coordination, from initial inquiries to post-installation follow-ups. She serves as the primary contact for customer communications, maintaining SashWise's commitment to exceptional service.

Tim

Senior Window Fitter

Tim leads on-site installations and complex restorations, bringing 15 years of experience in timber window craftsmanship. His expertise in heritage joinery techniques ensures precise execution of traditional methods while integrating modern performance enhancements for durability and energy efficiency.

Jay

Senior Window Fitter

Jay specialises in sash window mechanics and security upgrades. With a decade of experience, he excels in diagnosing window issues and implementing solutions that restore functionality while maintaining period authenticity, ensuring optimal performance and client satisfaction.

Thomas

Trainee Window Fitter

Thomas is training in all aspects of window fitting and restoration. His attention to detail and enthusiasm for traditional craftsmanship support SashWise's commitment to nurturing skilled professionals who uphold the company's high standards in future projects.

Questions

What areas do SashWise cover for window services?

We serve West London and surrounding areas including Twickenham, Richmond, Kingston, Wimbledon, and Surbiton, covering both period and modern properties.

Do SashWise offer draught proofing with VAT exemptions?

Yes, we charge 0% VAT on all draught proofing work, making energy efficiency improvements more accessible for homeowners.

How does SashWise contribute to environmental sustainability?

We partner with Ecologi to plant a tree per order and use FSC-certified Accoya timber, combining sustainable practices with carbon-reducing initiatives across our operations.

Can SashWise restore original sash windows effectively?

Our team specialises in sympathetic restoration, repairing rot, replacing damaged components, and refinishing surfaces to preserve historical integrity while enhancing functionality.

What makes SashWise different from other window companies?

We combine traditional craftsmanship with modern techniques, offering tailored solutions for period properties while maintaining a strong focus on sustainability and customer satisfaction.

Do you provide guarantees for window installations?

Yes, we offer comprehensive guarantees covering workmanship and materials, including 20-year colour stability warranties on aluminium window finishes.