From family homes to older stone and slate houses, we add space, renovate and build patios across this part of Gwynedd.
Tell us where you are and what you need, and we'll arrange a time to come and look.
Gwynedd Construction Ltd has been building in North Wales as a limited company since 2016.
Book a free estimatePorthmadog, Tremadog and Criccieth sit between Eryri, the Llŷn coast and the Ffestiniog slate landscape, so more planning rules apply here than almost anywhere else in Gwynedd. Here is what each kind of job looks like in this area.
Family homes in Porthmadog and Criccieth often need more room downstairs – a kitchen-diner or family room on the back of the house.
Porthmadog town centre has been a conservation area since 1974, and Tremadog and Criccieth have their own. West of Criccieth, much of the coast is in the Llŷn AONB. In all of these, the extension rules are tighter.
New homes here may come under Gwynedd Council or the Eryri National Park Authority, depending on the exact address.
Every new home needs sprinklers, and most need SAB approval. Plots near the Glaslyn may also need to show they won't add phosphate to the river.
A garage conversion adds a bedroom or office without building out – useful where the garden is small or the plot is protected.
Inside the National Park, check with us first, because the rules are different.
Older stone and slate houses here were built with separate small rooms. Opening them up makes a better family space.
Thick stone walls need careful propping and a steel sized by an engineer.
Full-house and single-room renovations, including older stone and slate houses, are common in this area.
If the house is a holiday let or second home, or you plan to use it as one, check the rules first: planning permission is now needed to change a main home's use.
We take on plastering in Porthmadog and Criccieth as part of a bigger job, such as a renovation or extension.
Old Artex should be tested for asbestos before anyone sands or scrapes it.
Coastal gardens take a lot of wind and rain, so patios and walls need a good sub-base and proper drainage.
Slate suits the Ffestiniog and Porthmadog area well; porcelain is the low-maintenance choice.
This part of Gwynedd has a lot of protected places, so check early:
Rules change, so treat this as a guide – we check your address before you commit.
It depends on the exact address. Inside the Park boundary, it's the Eryri National Park Authority. Outside it, it's Gwynedd Council.
Planning permission is needed before a main home becomes a second home or short-term holiday let: in Gwynedd Council's area since 1 September 2024, and in Eryri since 1 June 2025.
Real words from real customers in Gwynedd, Bangor and Anglesey.
“Once the decision to FINALLY get a new kitchen was made the nerves set in. There was no need, Gavin and his team made everything right. Communication was excellent … And best of all done within timescale agreed. Very Happy.”
“I’ve used Gwynedd Construction on several occasions for general repairs in my office, and every time the service has been exceptional. Gavin, the owner, is professional, reliable, and clearly takes pride in the work his team delivers. … Highly recommended if you’re looking for quality workmanship in North Wales.”
“Can't speak highly enough of Gwynedd Construction Ltd. They completed the work on time and to an extremely high standard. Nothing was too much trouble … Will definitely use them again.”
“I must commend the excellent high-quality construction work that was delivered. … The planning phase was executed to perfection … the team's ability to effectively manage unexpected changes truly stood out. … 100% recommend.”
“Gwynedd Construction did an excellent job on the work i had done on my bedroom. They were very professional and polite. They cleaned up afterwards and you wouldn't have known they had done work on my bedroom.”
“Gavin and Geraint were extremely professional from our very first meeting. They are two hard working, trustworthy, reliable and extremely tidy workmen. … Can't recommend them highly enough.”
“Can't speak highly enough of Gwynedd Construction and the incredible work they did on our one-year renovation project. … What impressed us most was their ability to handle unexpected challenges with ease, offering creative solutions while staying on schedule and within budget.”
“The team built a large extension at the back of my property and a detached garage … I then had the team back to do a patio and a retaining wall. Also very clean and tidy workers … Good job Gavin and gang.”
“We are extremely pleased with the work that has been completed. … Everything was kept safely and out of the way at the end of the day. They all worked very efficiently to a very high standard.”
“A true craftsman, a master of his trade. A man of integrity and reliability always prompt and courteous. … I’d highly recommend this exceptional builder and his skilled team.”
“Gwynedd Construction provides excellent, quality professional service, project managed my extension, very impressive, on time and within budget, as well as offering innovative design advice along the way, highly recommended.”
“Hogia clên ac taclus iawn ei gwaith. Glanhau bob nos cyn gadael ac yn hollol ddi-drafferth. Awgrymu’r cwmni’n gryf!”“Friendly lads, very tidy work. They cleaned up every night before they left, and it was completely hassle-free. Highly recommend the company!”
“It was a pleasure to welcome this friendly professional and trustworthy crew every morning. Never let me down, in fact went out of their way to find solutions to unforeseen issues.”
A local builder you can reach on the phone, who turns up when they say and leaves the job tidy.
Based in Pontrug, just outside Caernarfon, with more than 15 years in construction.
Gwynedd Construction has been a limited company since 2016.
And 100% of people who reviewed us on Facebook recommend us.
From the groundwork to the plastering, so you're not passed between firms.
The site is kept clean as we go, and you're kept up to date the whole way.
As well as Porthmadog and Criccieth, we work across Gwynedd and Anglesey. Not on the list? Give us a ring and ask.
If you're inside the Park boundary, it's the Eryri National Park Authority. Outside it, it's Gwynedd Council. We'll help you check.
Yes. Call 07825 205657 or send the form below with a few details and photos.
Extensions, new builds, garage conversions, knock-throughs and kitchens, renovations, plastering and patios. See our services above.
Yes. We cover Porthmadog, Tremadog, Criccieth and the villages between.
Much of the coast west of Criccieth is. Inside the AONB, two-storey extensions can't be built under permitted development. We'll help you check.
Tell us a bit about the job. We'll come out, have a look and give you a free written estimate.