Our clients

Our amazing clients are the main reason
we work so hard.
See what they say about us.

We have recently worked with GBG Building Services Ltd. The project involved converting two very dilapidated flats, on different levels, into one high end fully reconfigured/renovated flat. The work was complex, not least because it is a Georgian building with difficult access. Mariusz, Eric and the team delivered the project on time, on budget and to an exceptionally high standard. In our experience, this is rare.


Working with a contractor for the first time is always a learning curve on both sides. We were pleased to find that Mariusz’s approach is very much in the spirit of collaboration. Our attention to detail does not make for an easy ride for a builder, Mariusz was patient and understanding about this. However, it’s the fact that he cares enormously about whether the client is happy, and his determination to deliver quality that makes him stand out. He is intelligent, motivated, responsible, entirely trustworthy and generally a pleasure to deal with.


The pace of the work and involved nature of the design meant there was the inevitable odd minor mistake (on all sides). However, in our view the sign of a good builder is their willingness to rectify things, and the grace with which they do this. Mariusz scored highly on both fronts. There are so many things to commend about the team – they turn up on time, work very hard, are considerate, skilled, and it’s a tidy and professionally run site. As a result, there were none of the common complaints from neighbours or our client. Mariusz prefers to keep almost everything under his umbrella and can provide an extensive range of services. This comes at a premium, which our client was aware of from the start, but he made the decision that the benefits were worth the extra cost. He is delighted with the results, which have far exceeded his expectations.

Mariusz and GBG Building Services did an excellent job on my total internal renovation of a 2-bed period maisonette in Hampstead. The project included a complete stripping back to the bare brick walls, changing internal layout and completely rebuilding the interiors. Mariusz and his team were responsible for the full build, including all decoration and joinery works. While some (other) aspects of the project were challenging, GBG were a pleasure to deal with throughout. The team were thoroughly professional, completed on time, and have delivered a very high standard of finish (I have had it complimented by others who have much more experience of building projects than I..!). Mariusz and site manager Eric have a strong work ethic and run a tight ship, and they have gathered a team around them that are polite, diligent and capable. Never once did I see a mess left on site – everything was kept ship shape and tidy throughout the 5 months, and my neighbours have expressly told me how impressed they were with how little disturbance there was. (Never a stray cigarette butt in the shared garden!)


For me this was my first major building project, and I’m delighted to say that my experience with GBG was nothing like the horror stories I’d heard about builders from friends and colleagues. Quite the opposite: at challenging times during the project GBG were a huge help and went the extra mile to help the project succeed. I warmly recommend them.

Mariusz and the team at GBG delivered a complex and comprehensive redevelopment project in Fulham that exceeded expectations. Mariusz was given a very restricted time frame and a challenging specification, but he pulled together the resources needed to complete the project on time. Mariusz is very intelligent, trustworthy and creative. I would not hesitate to hire him again for similar or larger projects

We recently had our St John’s Wood apartment in a Grade 2 listed building renovated by GBG. They have done a stunning job in terms of both finish and service, the only downfall was the timing due mostly to unforeseen issues with the old nature of the building and the tight spaces within which they had to work.

We had quite a bit of work done, with a mezzanine being installed, the bathrooms rebuilt, kitchen renovated, access to 2 office/spare rooms built and much more. They constructed and installed inbuilt wardrobes and storage as well as designed the inbuilt desks for the offices, and the trapdoor access to the offices.

Our build definitely would not have turned out as amazing as it had without them as they did much more than just build, they helped design and used a lot of common sense when they were under time pressure and didn’t have/ couldn’t get guidance from us.

We will be using them again when the time arises, and would definitely recommend them to anyone who is looking for a builder with an eye for quality and design.

Jonathan Freegard Architects are delighted to recommend Mariusz Gawecki and his team at GBG Building Services who have just completed a high-end residential refurbishment for our clients under our direction in Hampstead, North London. The job has been executed to a very high standard, on time and on budget. The planning and programming of the work have been exemplary and the building team has been helpful, obliging and considerate to the neighbours throughout. The team members have brought their own considerable skills to the construction process and interpreted our design intentions with intelligence. It has been a pleasure to work with them.

The Green H LLP worked with GBG on a challenging project in Kensington and Chelsea, London. GBG demonstrated great professionality in delivering under tight timelines and under pressure. They have been able to produce detailed Gantt charts of works on site and able to maximise resources to the best effort. Will highly recommend this company for any residential or commercial job which require skills and thoughtfulness.

GBG Building Services have been employed by us to carry out general contracting and specialist sub- contractor services on a number of projects, over the past four years. These have included The Paddington London Hilton, The Millennium Mayfair Hotel Grosvenor Square, and the Royal Automobile Club Piccadilly and have ranged in value from GBP 50k – GBP 1.4 M.

Their approach to the works at all levels has been both helpful and highly professional, their craftsmen, tradesmen and management, working with our own team to provide a finish to the highest of standards, very often within extremely tight constraints on both programme and finance.

I believe the company has grown in stature over the years we have been working together and is quickly becoming a name within the industry that companies like ourselves can respect and rely on, to carry out larger and even more prestigious projects in the future.

GBG Building Services Ltd were our preferred contractor following a careful selection process for a residential refurbishment in SW London. Although not a large project there were a few complex areas of focus to the design and we required a skilled workforce to evaluate and execute the project to a high standard.


From the initial meeting GBG provided with detailed review of the design from a structural perspective and together we were able to assess any constraints prior to the build, allowing the program to run smoothly.


Mariusz Gawecki is a sincere, polite and extremely professional Project Manager. His background in Civil Engineering is another distinct string to his bow and is a huge asset to the design process. With this experience at the helm we able to create a uniquely adept forum with our clients’ as the build evolved. In the end, Mariusz and Eric’s team were so incredibly efficient we completed the program ahead of schedule with a highly successful outcome.

Mariusz is a very professional builder and works hard to make sure the scope of work is well understood before he starts helping him to deliver on time and on budget as he did for us. The quality of the finished work is of a high standard and any issues that arose were dealt with promptly.

Hi Mariusz,

I want to take the opportunity of thanking you and Eric for the work you completed on

my house. The soundproofing project was extremely complex and as you know I obtained several quotes from established building firms before I decided to go with you .

The result has been frankly truly amazing, way beyond my expectations and even though it was expensive was worth every penny. I also was delighted the project was completed on time and on budget. The wardrobes really add to the bedrooms and my tenants whom you know have the highest standards are delighted with them also. I would have absolutely no hesitation in recommending you to any potential future clients and would be happy for you to show this e-mail if you wish.

May we take this opportunity to thank you at GBG for the works undertaken at the house we now enjoy.

From the initial contact through consultations, quote and actual works, we have been pleasantly surprised at the total involvement, advice, creativity and shear hard work that has been put into the project by GBG. This includes meeting budgets and timing. At no time did we have any concerns with GBG acting as project managers, especially with the exceptional liaison experienced throughout.

We are very grateful to GBG for the efficient and effective manner in which the work in our home was carried out. Your workforce was polite and reliable, turning up precisely when planned, which as we were living in the property was important. You sorted out the problems left by our previous builders and also provided finishing of an excellent quality. You brought with you many good ideas and suggestions which improved the result for us. It was both a pain-free and stress-free experience. Thanks.

GBG team must be one of the best contracts turn key operators I had the pleasure of working with during my long professional career as an international designer in the contract and private field.

Reliable, experienced, managing a multi-disciplined team tackling projects from concept to completion, achieving remarkable results, on time, on budget and to a very high standard.

GBG had the flair and technical ability to interpret client’s brief, manage and implement their requirement in an efficient and stress freeway. Projects are personally supervised, and Client is fully informed as to the progress of the work. Projects include residential and hotel work. Attention to detail regardless of size and budget.

A small company, highly skilled core team, top results!

Mariusz and Eric and their team were , throughout our time with them, reliable trustworthy hard working and FANTASTIC. Mariusz I think prides himself not only on  attention to detail but also discussing with the client beforehand and during the works, to ensure there are NO chances of misunderstandings/miscommunications.

To know the detail, to know the team are completely engaged 100% on your project is invaluable and so reassuring. We all take pride in our home, to each of us it is a special project demanding all the attention of the people working on your house. Mariusz and his team always, without fail, made me feel like our project was  as special to them too.

Everyday Mariusz was available , invariably on site. Eric and his team, small knowledgeable, familiar, reliable, respectful.

Its not just the end product that we are so happy with, its the way the project went. Mariusz effectively took all the pressures away  . All I ever found was a „can do” approach, alternatives solutions to any issue , and a positivity and knowledge that was invaluable.

GBG and Mariusz have a wealth of knowledge and experience which is all too easy to underestimate because Mariusz is such a modest guy.

Thank You Mariusz . Thank you GBG.


Mariusz and his team provided a very thorough and sympathetic renovation to our period property.  They not only were meticulous in their attention to detail both in making sure that the structural elements of the refurbishment were soundly executed, but they also spent a lot of time on restoring the period detail of the property, which has enhanced its character and individuality.  Their work was executed on time and on budget, and their approach was unfailingly positive and reliable”.

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