top of page
Garden Room Extension

Hello and welcome 

Celebrating over 35 years in Architecture

About GT Building Design

GT Building Design is a Chartered Architectural Practice based in the seaside town of Donaghadee, County Down. 


With over 35 years experience in Architecture, Glenn established GT Building Design in 2004 to help homeowners extend and improve their homes. Project experience includes extensions, attic conversions, alterations and new builds.


By appointing Glenn, you are assured expertise from one of the most experienced, reliable and trusted professionals in Northern Ireland today.

Glenn would welcome the opportunity to work with you on your project and as a chartered professional can:

  • Help you achieve your aspirations and vision

  • Add value to your project through good design and sound construction detailing

  • Bring creativity to your project whilst keeping it on track

  • Guide you through the design process

  • Help you obtain Planning and Building Control approvals

  • Give you peace of mind

To work with Glenn

If you would like the opportunity to work with Glenn on your project, click the button below and complete the form for support and request a quotation.

  1. No obligation introductory call to discuss your project.

  2. Written Quotation outlining fees and stages.  

  3. Measured survey of your home. 

  4. Preparation of Design Proposals for approval by you.

  5. Planning Application. 

  6. Building Control Application. 

  7. Selecting the right builder for your project.

  8. Support on Site.

Stay Updated!

To discover advice, tips and all the latest news don't miss Glenn's Blog. 

Google 5 Star Reviews

Allwyn Corrin

Within a tight time frame Glenn worked quickly and efficiently to draw up plans for a beautifully designed extension to my bungalow. He was very professional, patient and helpful at all times, dealing promptly with any queries. He kept me informed throughout the whole process, and I was really delighted with his service.

Best Residential Extensions & Conversions Architecture Company 2023 - Northern Ireland  ​

GT Building Design / Glenn Thompson 

Best Residential Extensions & Conversions

Architecture Company - Northern Ireland

Best Architectural Technologist (Northern Ireland)

GT Building Design / Glenn Thompson

Best Architectural Technologist Northern Ireland

& Residential Architecture Studio of the Year 2024

bottom of page