uPVC Sash Windows, Vertical Sliders, Box Sash

Timeless Style, Modern Efficiency

uPVC Sash Windows

Are you searching for top-quality uPVC Sash Windows, Vertical Sliders, or Box Sash windows replicating traditional styles for your period property? Look no further than our uPVC Sash Slider Window. Our design and installation services are perfect for all-period homes, from smaller Victorian or Edwardian terraced houses to larger Georgian stately homes. Our authentic-looking uPVC Vertical Slider Sash Windows feature Ovolo finishing details, blending modern materials and functionality with traditional design and character.

No Salesman Pressure

At Southeast Windows, we take a unique approach to sales. Since our team operates on a non-commission basis, you won’t feel pressured into making hasty decisions. Take your time to research and share your project requirements and concerns. We understand that every project is unique and prioritise addressing your needs. We are here to answer your questions and clarify, ensuring you feel valued and confident throughout the process.

Maintaining Traditional Style

If you want to maintain the classic style of your uPVC Sash Windows, Vertical Sliders, or Box Sash replacements, we can replicate them with Georgian Bar inserts. These inserts are placed between the glass panes or on the Astragal bar on the outside, creating the appearance of multiple glass windowpanes. For a more visually appealing look, we also offer sash horns with a run-through design, which are superior to clip-on alternatives.

Improved Insulation and Design

Many existing uPVC Sash Windows, Vertical Sliders, and Box Sash windows suffer from rattling, draughts, and poor energy efficiency. However, advancements in window technology allow us to improve your home’s insulation. Our vertical sliders can achieve U-values as low as 1.2 W/(m²K), enhancing soundproofing and energy efficiency. Additionally, the design maintains the original box sash window aesthetic, providing a visually pleasing upgrade.

Craftsmanship and Quality Control

Our uPVC replacement Sash Windows, Vertical Sliders, and Box Sash windows are crafted using advanced manufacturing techniques and undergo strict quality control. These windows significantly improve upon existing box sash windows, offering exceptional performance and durability. Our high-performance PVC-U sliders come in various colours and hardware options, including child restrictors, ensuring they complement any home. We are confident that your new installation will satisfy your expectations.

Legacy Vertical Slider

Introducing our Legacy Sliding Sash Window—a timber-look alternative that seamlessly blends elegance, British craftsmanship, and A-rated energy efficiency. This heritage-inspired design offers security and ease of operation, with a slim midrail and deep bottom rail for functionality. The traditional weather bar adds character, making our uPVC Vertical Slider Sash Windows look even more authentic to timber.

Our uPVC Vertical Slider Sash Windows have been tested against wind speeds up to 120mph, earning a 1200 rating. Additionally, they withstood being sprayed with eight litres of water per minute for 40 minutes without any leakage, achieving a Class 6A classification for water tightness.

Installation Options

Cill with Deep Bottom rail.

Astragal Bar in small midrail bar

You can choose from various customisation options for your installation. For example, depending on your preference, you can replace the existing frame architrave with hardwood, softwood, MDF, or uPVC trims. If the original plaster has degraded over time, repairs may be needed after installation. We ensure the area is ready for decoration once the work is completed.

Hardware Options

Our uPVC Vertical Slider Sash Windows come with white hardware as standard, but you can customise them with Brass, Chrome, Satin Chrome or Black finishes. Child safety locks can also be installed for added security, limiting the sash opening to 100mm.

Energy Efficiency and Compliance

Our uPVC Vertical Slider Sash Windows have an A energy rating, meeting the requirements of Approved Document L for energy conservation. They are also Building Regulation Part B compliant for fire exit status. As a FENSA-registered company, we provide documentation for FENSA self-assessment, and our windows come with a 10-year guarantee for added security and peace of mind.

Want to know More?

Call us today for your FREE, no-obligation quotation or fill out our Contact Form! For the most modern, energy-efficient replacement Windows, Doors and Conservatory with a 10-year Insurance Backed Guarantee for complete home Comfort & Designed to Keep You Warm, Safe, & Secure.

Alternatively, call your local number below to arrange an appointment.

East London uPVC Sash Window: 020 8472 4088 (head office)
South London uPVC Sash Window: 0203 856 6667
North London uPVC Sash Window: 0203 856 6669
Chelmsford uPVC Sash Window: 01245 208 058
Romford uPVC Sash Window: 01708 2 02 457
Great Dunmow uPVC Sash Window: 01371 704 771

Trust Southeast Windows Ltd to offer elegant, high-quality replacement uPVC Sash Window.

huong Luc

14:01 19 Dec 24

The team was led by Peter - great comms, double glazing patio door to insulate the ground floor bedroom, replaces single glaze door. After installation there was a slight problem but it was resolved in good time. Thank you.

Laurence Radford

15:17 19 Nov 24

Roy and team did an excellent and professional job replacing 3 front windows, making the change unnoticeable from the outside. They were worked with challenges getting large frames into the upstairs room and were courteous throughout. Would recommend.

Kate Cleaver

11:03 14 Nov 24

Really happy I chose Southeast Windows to fit my UPVC back door. Roy was friendly, professional and helpful at every step of the process. I was very happy with the workmanship and it was done so efficiently and with so little mess. I definitely recommend for a first class service !

Derek Wong

08:30 30 Oct 24

I would like to express my heartfelt thanks to Southeast Windows for their exceptionally good service. From the moment I reached out to them, their team demonstrated professionalism and efficiency that truly impressed me. The installation process of double glazing was remarkably fast, allowing me to enjoy the warmth of the new windows brought sooner than expected.Moreover, I was particularly impressed with the cleanliness maintained throughout the whole installation project. The team took great care to ensure that my home remained tidy, leaving no mess behind. This attention to detail speaks volumes about their commitment to customer satisfaction.Besides, the quality of the windows is outstanding. The windows not only enhance the aesthetic appeal of my home but also provide excellent insulation. I am thrilled with the results and would highly recommend Southeast Windows to anyone in need of window services. Thank you Roy and your team once again for your hard work and dedication!

Marc Jones

12:47 21 Jun 24

Amazing company and service. High quality work at very good price. Very efficient with great communication throughout. Would 100% reccomend.

David Gridley

11:10 07 Sep 23

Excellent work from Roy and his team. He installed our windows quickly and with a minimum of dust etc. They also took away the old windows which was a great help.

Arnold Cabanus

21:11 06 Mar 23

We recently had all our old windows replaced and installed by Southeast Windows. Everything, from the survey to the installation day runned smoothly .We are delighted with the excellent window installations that they did and left our house clean and tidy after. This company is very trustworthy , professional and courteous. If you need an honest and efficient windows installation company, definitely Southeast Windows Ltd is highly recommended.

Leah Corney

16:38 10 Feb 23

We chose southeast windows to replace our old upvc windowsfrom initial survey company were very informative explaining different options available fensa warranty fire regs etcquotation was very competitive detailing all widow specifications everything what we was getting including removal of all rubbishSo glad We went with triple gazing option not that much extraguys arrived early every morning we’re courteous and professional at all times did a fantastic job of installing windows clean and tidywindows look fantastic house is so much warmer and noise reduction really please we choose this company would definitely use againHighly recommend

Steve Clare

16:01 04 Oct 22

Had the double-glazing at the front of my house replaced. Really impressed with the quality of the work and the value for money. Roy is a real expert. All in all, absolutely delighted and very happy to recommend Southeast Windows. Five star review.

Hilary Armstrong

15:11 08 Sep 21

Roy and his team fitted new windows and French doors in our house earlier this year (we wanted to live with them for a while before reviewing!). We are really pleased with the quality of the windows and the service from Roy. He's a real gent to deal with and is punctual and professional. His quote wasn't actually the lowest but he was the only one to supply full details of materials, give fire safety and security advice, send a detailed quote etc. Thank you Roy

Megan Monaghan

10:33 04 Jun 21

I got quotes from a few companies however Peter was the only one who followed up to my questions on email so I decided to go with Southeast Windows. I am super glad I did, as Peter was professional and I am really happy with the work done in installing a new PVC backdoor and replacing glass in several windows. Peter was knowledgable, friendly and didn't take advantage of my lack of knowledge of window and door installation like some other builders have, being a first time home owner.I wouldn't hesitate to recommend Peter and Southeast Windows, I will for sure be using them again if I need. Thank you Peter!