An independent testing and certification company has launched its own stringent new scheme to tackle the reputation of poor quality bi-folding doors in the marketplace. Despite other brands – including aluminium door sets – failing the exacting test requirements, the PVCu Liniar ModLok™ bi-fold is the first to successfully pass.

The Folding Sliding Door Scheme has been devised by Build Check to raise the bar and bring a greater degree of excellence and reliability to a product that is still increasing in popularity, in spite of some negative publicity from some homeowners who have been the victims of inferior installations.

Many aluminium systems, often perceived as much stronger and more durable than its PVCu equivalent, have so far fallen short of the mark during these tests – whereas the Liniar ModLok™ bi-fold has passed with flying colours to disprove a common misconception.

Established in 2004, Build Check operates throughout the UK and Europe and has gone from strength-to-strength to become a highly respected provider within the marketplace, operating a management and quality system conforming to ISO/IEC 17025 (Testing) and BS EN 17065 (Product Certification) and accredited by UKAS and the BFRC.

Richard Bate, Build Check’s Technical Director, explains why they started the scheme: “There are a lot of poor quality bi-folding doors available out there at the moment. We decided to launch this scheme to assist homeowners in being able to choose a product that would be robust and fit for purpose.

“This makes sense for companies too. If they can provide a quality product then it will save them time and money in the long run on call-outs, repairs and replacement parts.

“We set the scheme up in August 2014 but have been unable to publicise it as we have been waiting for a product to successfully pass our stringent requirements – and we’re very pleased that the Liniar ModLok™ bi-fold door is the first to achieve that.”

There are three main sections to the test. Each product is put through 5,000 cycles by Build Check’s articulated robot, weather tested to 800 pascals (a wind speed of more than 80mph) and able to achieve a minimum U-value of 1.8.

“We’ve put several other bi-folding doors through the test, including aluminium doors as well as PVCu – and Liniar was the first to pass,” says Richard. “People might be surprised to hear that some of the doors did not even achieve 10% of the required cycles!

“Our whole intention for this scheme is that it will be difficult to pass. There would be no point in launching it unless it was going to encourage companies to raise their standards and aim for their product to be the best.

“Now that Liniar has achieved the required test levels, it can cascade the evidence to its fabricators. The fabricator will then be able to apply to Build Check to join the certification scheme and, subject to successful auditing of their quality system, manufacturing, installation processes and documentation, will be able to use the Build Check Folding Sliding Door Scheme mark.

“It’s taken until now for us to be able to announce a successful candidate but we believe that Liniar’s success will set the benchmark for other companies to aspire to.”

Chris Armes, Liniar’s Design and Development Manager, is delighted with the news.

“We’re very proud that the Liniar ModLok™ bi-fold is the first to successfully meet the testing requirements of the scheme. Obviously we have tested it excessively ourselves and have every confidence in the product. We’ve already put the bi-fold through its paces with our own in-house robot, which achieved 127,800 full opening cycles – but it’s good for its durability and robustness to be confirmed by an independent party.

“We’ll now be looking to increase the scope of our accreditation by expanding the dimensions of future test specimens and we look forward to continue working alongside Build Check.”

For more information on Build Check go to: or call: 01494 452713.

To find out more about Liniar go to: or call: 01332 883900.