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Installation & Measuring Guides

Our installation guides offer clear, step-by-step instructions for fitting our products with ease. Each guide includes helpful diagrams and tips for a seamless, professional installation. Trust our expert guidance for a flawless result every time.

Horizon Windows & Doors
5.0
Based on 20 reviews
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Romica Visan
12:02 17 Oct 25
Guy Maddison
10:35 09 Oct 25
Purchased new windows for a job we are doing for a customer in Portsmouth. These guys are great. Very responsive and know what they are talking about. They also keep up with building regulations to make sure everything they supply meets the standard. Thanks!!!!
Danny
10:21 09 Oct 25
Bought a set of bifolds very swift with delivery and good quality product. Thanks
daniel clark
13:03 15 Jul 25
Bought a bifold door and two windows
Great price and swift delivery!
Thanks.
Steve Winterberg
18:52 29 Jun 25
I have been using Horizon windows and doors on our properties and those of customers for over 10 years now and never ever had anything other than 1st class service and quality - light tunnels, roof lights, french and sliding doors, windows in plain, woodgrain and painted finishes and the replacement of blown sealed units originally fitted by others. Thoroughly recommend! Great company with 1st class professional staff.
jason knight
17:42 19 Jun 25
Bought a set of bifolds for new extension. Great guidance and friendly service from josh and his team. Product arrived on time and excellent quality. Very pleased and warm friendly family run business
Dan Ette
19:02 18 Jun 25
Great service
Imogen Farrell
17:55 18 Jun 25
Great experience! Ordered bifold doors and a roof lantern, everything arrived on time and looks amazing. Good prices, helpful support, and solid quality. Would definitely use them again.
Nicola Lilley
08:13 15 Jun 25
Great service- Window was installed quickly and promptly. Thanks so much. Would recommend!
Robert Belcher
15:46 14 Jun 25
Supplied and fitted a set of bi-fold doors in our new extension. Good workmanship and took away all waste afterwards. The doors look great and its really finished off our new patio area. Thumbs up ?
John Varndell
18:22 08 Apr 25
James Black
10:43 26 Mar 25
I used horizon windows & doors to carry out some work on our extention.. the quality of work and service received was excellent... highly recommend...
Vincent Dunne
21:03 20 Mar 25
We recently had bifold doors and windows installed and we couldn’t be happier with the results! From start to finish, their team was professional, knowledgeable, and incredibly helpful.

The quality of the doors and windows is outstanding and clearly built to last. The installation process was smooth and efficient, with great attention to detail. They kept us informed throughout, ensuring everything was perfect. Highly recommend to anyone looking!
Steven Wight
20:51 19 Mar 25
I used horizon for windows for my extension, we had a great service from start to finish we are using them again later in the year to replace the existing house windows after seeing the quality of the ones for our extension, super pleased with them.
Emine Holden
20:45 19 Mar 25
I purchased five windows for my home, and the experience was seamless. The team was professional, efficient, and very helpful throughout the process. Highly satisfied with their service!

Brett Martin Roof Lantern

Click here to open the Brett Martin Roof Lantern guide

Brett Martin Flat Glass

Click here to open the Brett Martin Flat Glass guide

Brett Martin Mardome Trade

Click here to open the Brett Martin Mardome Trade guide

Brett Martin Mardome Circular

Click here to open the Brett Martin Mardome Circular guide

Brett Martin Mardome Smoke Vent

Click here to open the Brett Martin Mardome Smoke Vent guide

Korniche Roof Lantern

Click here to open the Korniche Roof Lantern guide

Click here to download the Korniche Roof Lantern Measuring guide

Korniche Bifolds

Click here to open the Korniche Bifold guide

Korniche Flat Glass

Click here to open the Korniche Flat Glass guide

Click here to download the Korniche Flat Glass Measuring guide

Cortizo 4700 Sliding Door

Click here to open the Cortizo 4700 Sliding Door guide

Atlas Lantern

Click here to open the Atlas Lantern guide

Atlas Square Lantern

Click here to open the Atlas Square Lantern guide

Atlas Flat Roof

Click here to open the Atlas Flat Roof guide

Atlas Skyroom

Click here to open the Atlas Skyroom guide

Horizon Edge Flat Roof

Click here to open the Horizon Edge Flat Roof guide

Horizon H1 Lantern

Click here to open the Horizon H1 Lantern guide

uPVC Sliding Sash Windows

Click here to open the uPVC Sliding Sash Window installation guide

Sash Window Hardware

Click here to open the Sash Window Hardware guide

uPVC Casement Windows

Click here to open the uPVC Casement Windows guide

Aluminium Windows

Click here to open the Aluminium Windows guide

Bay Windows

Click here to open the Bay Windows guide

 

Aluminium Sliding Doors

Click here to open the Aluminium Sliding Doors guide

Slide and Fold Doors

Click here to open the Slide and Fold Doors guide

Internal Doors

Click here to open the Internal Doors guide

Composite Doors

Click here to open the Composite Doors guide

Cortizo 4700 Sliding Door

Click here to open the Measuring Guide & Technical Information

Click here to open the Configuration Guidelines

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