— 01
External Wall Insulation Systems
Complete, high-performance EWI systems that wrap your property in insulation — dramatically improving warmth, energy efficiency and weather protection.
Jersey — External Wall Insulation Specialists
External wall
insulation specialists.
Jersey's dedicated external wall insulation specialists. We transform homes and buildings with high-performance insulation systems and flawless silicone render finishes — warmer interiors, lower energy bills and standout kerb appeal, delivered start to finish.
Or call direct
+44 7700 357027
20+
Years Experience
100%
EWI Focused
5★
Client Rated
Jersey
Based & Trusted
01 / Services
What we do.
We focus on one thing and do it exceptionally well. As Jersey's external wall insulation specialists, we install complete EWI systems and finish them with high-quality silicone render — for private and commercial properties alike.
— 02
Silicone Rendering
A flawless, crack-resistant silicone render finish over your insulation — self-cleaning, breathable and available in a wide range of colours and textures.
02 / What We Do
The insulation
specialists.
Founded by Gary Mc Geoghegan in 2017, GMAC has become Jersey's dedicated external wall insulation specialist. We don't spread ourselves thin across every trade — external wall insulation and silicone render finishes are all we do, and we do them to an exceptional standard.
- Specialists in external wall insulation
- Warmer homes & lower energy bills
- Flawless silicone render finishes
- Trusted on private & commercial projects
03 / Transformation
Insulated & transformed.
From tired, uninsulated walls to a warm, weatherproof and beautifully rendered exterior — see what a full external wall insulation system delivers. Drag the slider to reveal the transformation.
Before
After
⇆
04 / Process
How we work.
No vague timelines. No surprise costs. Every external wall insulation project moves through the same four stages, communicated clearly from day one.
01
Survey
We visit and survey your property, assess the walls, and recommend the right insulation system and render finish. No pressure, no obligation.
02
Detailed quote
Clear, all-inclusive pricing in writing — materials, labour and timeline. Full transparency on every cost, with no surprises at the end.
03
Install & render
Insulation boards fixed and reinforced, then finished with a high-quality silicone render — applied by our specialist team for a durable, weatherproof result.
04
Walk-through
A final inspection together. We keep the site tidy throughout and don't sign off until you're standing in front of it, delighted.
05 / Portfolio
Recent work.
A selection of recent external wall insulation projects across Jersey — high-performance systems finished in silicone render. Real homes, real transformations.
External Wall Insulation
Silicone Render Finish
Insulation System
Render Detail
Completed Project
Finished Exterior
06 / The Difference
Why GMAC.
There are plenty of general builders in Jersey. Few are true external wall insulation specialists. With a wealth of experience — working locally, in the UK and Ireland — we focus on one thing and do it exceptionally well.
-
01
True specialists
External wall insulation and silicone render are all we do. That focus means deeper expertise and a better, longer-lasting result.
-
02
Warmer, cheaper to run
A properly installed EWI system dramatically improves thermal performance — warmer rooms and noticeably lower energy bills.
-
03
Flawless render finishes
We finish every system in high-quality silicone render — crack-resistant, self-cleaning and available in a wide range of colours.
-
04
Clean working, on budget
Clear quotes, tidy sites and efficient project management. Your job is done on time and on budget, every time.
07 / Client Reviews
What our clients say.
Don't take our word for it — our reviews speak for themselves. Real words from real Jersey homes and businesses we've worked with.
"GMAC are a very professional service. Clean workers, got the job done quickly with a great finish. I'll use them again and would highly recommend them too."
C
Chris De Malorey Romeril
Professional Service
"I called Gary for a quote on a Wednesday afternoon and he was with me within a couple of hours. Arrived promptly the next day and the whole job was finished well within the promised timescale."
J
James Eden
Fast & Reasonably Priced
"Gary & his lads have done a fantastic job on our house, and we would certainly recommend GMAC to anyone."
A
Allan Shaw
5 Stars
"Great service as always. The job was done on time and to perfection, as you can see in the photos. Thanks GMAC."
G
Greg Kelly
Great Service
"Gary is a little grafter and super reliable. We've used him numerous times now and will without doubt again in the future."
L
Lyndsey Stirling-Stewart
Super Reliable
Worked With Us? Share Your Review.
Your honest feedback helps other Jersey homeowners and businesses find an insulation specialist they can trust. It takes less than a minute.
Review on Google08 / Careers
Join the team.
We're growing, and we're looking for grafters who take pride in the finish — experienced hands and keen learners alike. We focus on one trade and do it exceptionally well, which means consistent work, real skills development and a finish you'll be proud to put your name on.
Steady work
A full project pipeline across Jersey means consistent hours and reliable income — not stop-start contracting.
Specialist skills
Learn external wall insulation systems and silicone rendering — in-demand specialist skills that set you apart.
Tight team
Work directly with Gary and a small, skilled crew. No layers of management — just good people doing good work.
Pride in the finish
5-star rated by clients across the island. Join a team known for doing the job right, first time, every time.
What we're offering
- Competitive rates, paid on time
- Steady, year-round project pipeline
- Specialist EWI & silicone render training
- Quality tools, kit & site support
- A tight team that takes pride in the work
-
01
Send your application
Complete the short form with your details, the role you're after and a quick summary of your experience.
-
02
Quick chat with Gary
If it looks like a fit, Gary will call you for an informal chat about the role, rates and start dates.
-
03
Trial day on site
Join the crew for a paid trial day so both sides can see it's the right fit — then we get you started.
09 / Get in Touch
Let's get your project started.
Tell us about your property. We'll survey the walls, recommend the right insulation system, and give you a clear, all-inclusive quote in writing.
Phone
Email
Opening Hours
Mon – Sat · 07:30 – 18:00