We are an established and vibrant company based in Mill Hill who has completed a lot of extensions, loft conversions and refurbishments in London in recent years, delivering exceptional costumer satisfaction and great value for money.
We offer
· Great value for money-with no hidden costs.
· Guaranteed work-6 years guarantee under JCT contracts
· We are a member of FMB including Trustmark.
· Our clients are happy to speak to you to confirm our reputation.
· Structure engineer on site throughout the building process.
· Designer if needed to help you decide.
· All trades are fully qualified.
· We have Liability Insurance and Professional Indemnity Insurance to give you the peace of mind.
  If you would like to know more about our company we would be happy to carry out a free assessment, quotation and arrange for you to visit one of our completed projects local to you.

Trades offered

Garage Buildings/Garage Doors
Builder general
Basement/Cellar conversions
Loft conversions
General extension
House Builder
New build
Custom/Self Build
Wall tiling
Floor tiling

Case studies

Where space matters

  • 14 Aug 2020
  • St Albans

Back extension, loft space and internal remodelling

  • 16 Feb 2020

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Customer testimonials

03 Aug 2020

As an RIBA Chartered Architecture practice we have worked with many contractors over the years. We have been absolutely delighted with the quality and service provided by Triangle Construction on two recently completed house refurbishment projects. Both involved the modification and total upgrade of a whole house, including complex structural steel installations, new services and new finishes throughout, but both finished on time and on budget, to an excellent quality of finish with impressive attention to detail. Altin, Esmeralda and the team were attentive and easy to work with. We will definitely be proposing them to our clients again… we only wish we had discovered Triangle Construction sooner!" - Fiona


21 Jan 2020

Excellent experience. Altin delivered to time, cost and quality. 100% recommend Altin and his team to others for all renovations or building works. Happy to offer reference visits to any potential clients. Our house required a full internal renovation with extension work. We had a local architect draw up plans and obtain permitted development approval. We were introduced to Altin via a colleague and also spoke to other clients, and saw his work first hand. Of the 4 builders we got to quote, Altin was the one who gave us the most confidence that he could deliver to the cost, quality and time we wanted. This proved to be the case. This was a relative stress-free experience. The project took 5 months once work commenced. This included Altin accommodating a few changes to the design and some extra work. He quoted for this in advance with rates that were fair and reasonable. Altin's background as a qualified engineer shone through in his ability to identify issues and recommend options. One example was the roof design which was not fully detailed in our plans. Altin proposed an option and commissioned a structural engineer to draw up the plans. His experience of working on houses of this age was also invaluable. He was prepared for problems with damp, poor foundations and uneven floors. The level of professionalism shone through in all aspects of the work. From the initial introduction to the neighbours to the final decoration and finishings. Altin is very hands on which commands the respect of his team and his customers. We decided to avoid the cost of a project manager / architect so took on the responsibility of working directly with Altin. This ensured quick decision making and probably contributed to the short completion time. Altin was very good at communicating progress and laying out when decisions were required. As long as you have the knowledge and time to do this, I would recommend it. - Andy


06 Jun 2019

"In both experiences (2010 and 2018/19), the work has been delivered to the high standards expected, and within 5 and 1/2 months as planned. Any extra structural work necessary, that was unplanned has been flagged in advance, was discussed and agreed together for it to be reflected in the overall budget. From a cost perspective, certainly not the cheapest but quality which is fundamental in delivering structure is essential and well worth paying for. The building site, was safely covered, to limit disrupting to the neighbouring properties, with the adeguate roof temporary covering and scaffolding sheets. There are cowboys out there that simply don't care about neighbours or quality. Altin team is the exact opposite. Altin Ndoni himself, in charge, is a highly experienced and trained civil engineer that goes well beyond simple execution, working in close collaboration with the architect and structural designers to ensure the best for the project. Solid structural work is delivered to high standards of professionalism by all his crew, tidy, clean, patient, quiet and smiley people. A real pleasure to work with closely. Praised by both neighbours. It did require quite a hands-on role from my side, which I thoroughly enjoy. the carpenter team went beyond the routines job with some bespoke joinery and carpentery that was decided along the way. Good kitchen fitting skills as well. good plumbing and electric teams." - Elena


29 Aug 2018

"We first used Altin and his team from Triangle Construction in 2014, after strong recommendation and seeing some of his work, to complete a loft conversion and refurbishment to the upper floors of our house. We were extremely happy with the results and were confident that he would be our contractor of choice for the second stage of our project. Triangle Construction recently completed major works to the ground floor of our Victorian house, incorporating structural glazing to create a contemporary kitchen, utility and w.c and refurbishment of the living area and garden. Altin and his team are immensely hard working, honest, reliable and efficient with tremendous pride in their work. We cannot fault them and would use them again without hesitation." - Roksana


15 May 2017

We employed Triangle Construction to build our dream home. We received several quotes from local builders, as it was a large, complicated project and even if Triangle was not the cheapest, we do not regret our decision. Altin’s qualifications on structural engineering and his experience in construction, reassured us that they were the right team to take on the build. Altin dealt with other companies (Thames Water, National Grid, BT etc ,as it was a new build and it needed services connected) in a very professional manner, updating us weekly about the progress of the work. He was patient, polite and considerate. He kept to the time given and there were no unexpected costs involved. The quality of the finish is excellent. The house is truly beautiful. I highly recommend Triangle Construction. - E.Q

Mill Hill

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