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Installing and maintaining interior doors correctly


Can non-professionals install an interior door correctly? The internet is teeming with do-it-yourself (DIY) videos and instructions for installing interior doors. Examples include the fact that the assembly of an interior door made of wood is "moderately difficult" and takes around three hours. On the other hand, the smiling and stylish young couple in the film seem to be able to complete the work in only 5 minutes. Hard to believe, even though the video has several hundred thousand call ups! How do you assemble doors correctly and securely? What happens if something goes wrong during DIY erection? And what role does professional maintenance play with interior doors?


Professionals install the standard interior door in one hour.

"If someone has never installed a door before, then I say: Hands off!" warns Holger Stretz and clearly advises inexperienced laymen against DIY door installation. As a master carpenter, owner and managing director of Stretz GmbH in Westheim, he knows what he's talking about: his company has been providing advice on door purchases, delivery, installation and maintenance for over 50 years - from private homes and apartment blocks to large construction projects such as apartment complexes, office buildings and industrial buildings.

Three hours to install an interior door? "If there are two of us, it can be done professionally in just over an hour," says Holger Stretz from experience. Of course, installing a standard interior door is not "witchcraft". Skilled craftsmen can do it.



No DIY trend for the erection of high-quality interior doors

On the other hand, this requires a particularly professionally equipped toolbox: But what layman has a Lamello plate, door lining spreader and a 1.80 metre spirit level? But if you don't have the right tools, mistakes can be made with serious consequences: because if the plumb line and rebate dimensions are wrong, the installation result cannot be right.

The Stretz team has already had to dismantle and reassemble a door that was not installed correctly by a layman. An effort that the buyer could literally have saved himself.

In general, Holger Stretz does not see a DIY trend in door installation among his customers. Because: "People who opt for high-quality doors don't tend to cut corners when it comes to installation."

Door maintenance: a "must" once a year

It's written in black and white on the invoice: the new interior door should be professionally serviced once a year. Failure to do so will invalidate part of the guarantee.

Does the door close properly, does the rubber seal fit correctly, do the lock and hinges function smoothly? Annual door maintenance is a good investment even for private single-family homes: without maintenance, however, the guarantee on moving parts of technical doors, for example, is invalidated.


How can I recognise a door specialist?

You can recognise a door expert by their professional profile and appearance. This includes

  • Qualifications: carpenters, joiners or experienced fitters - in a professional company, every employee receives regular specialist training. GARANT also regularly invites business partners, such as Stretz GmbH, to seminars and training courses on all aspects of interior doors.
  • Professional tools: The installation vehicle contains a well-stocked range of tools for door installation, maintenance and repair.
  • Care and attention: Before starting the installation, the experts cover floors and surfaces to protect them from damage and dirt. At the end of the work, the professionals clean the site.
  • Entry in the trade register or membership of a professional association: Recognised, well-trained specialists work here.
  • Complaints and a clean finish: The company also sends specialists back after the installation if there are any questions or defects.


DIY installation of functional doors? No way!

There are no "experiments" or DIY for functional doors. This is because not only does the warranty expire for a fire door, but the test certificate and insurance cover are also no longer valid. After all, this door can even be life-threatening in the event of a fire if it has not been installed and approved by a specialist. After all, only a specialist can guarantee that all the requirements of the test certificate have been met.

The trained fitter ensures that a functional door is permanently and securely installed in the correct position in the wall. The DIN standards regulate the details, including the wall material, the type of plugs and how they are to be fitted. Another must for these doors: professional maintenance once a year.


We are at the building site a lengthy time before the start of the work, because we take our own measurements. Also for private customers. This is how we ensure the important sizes and specifications for doors and windows, regardless of the size of the building project. The client realises that we are professionals as early as the consultant stage. Visitors feel that they are in good hands as soon as they walk through the GARANT showroom. This is because our people are constantly being trained and therefore know all about interior doors.
Holger Stretz Inhaber und Geschäftsführer der Stretz GmbH

Installing and maintaining interior doors

50 years of door expertise and a GARANT partner from the very beginning: stretz-tueren.de