ultra slim sliding doors

Slimline Doors and Windows

Slimline doors and windows, also known as minimalist, or ultra-slim doors and windows, comprise those products where the sightlines are smaller and less visible than regular windows and doors. With many of these slimline products, it’s the installation itself, with hidden frames resulting in minimal looks or appearance of frameless doors and windows.

The range of windows and doors marketed as slimline is frequently confusing. Consequently, it’s important to understand the difference between these many marketing messages and the genuine slimline and minimal or near-frameless product.

Information about slimline or ultra-slim doors and windows

First of all, most of the ultra-slim doors and windows tend to be upper-tier systems and therefore cost more than regular windows and doors. Often these systems come with engineering and design intended for large sizes and contemporary architectural glazing. As a result, they come in more expensive systems.

Furthermore, doors and windows of this type frequently rely on the glazing for structural stability. In other words, the slimline aluminium may not provide the strength required owning to its smaller proportion. Alternatively, while slimline and ultra-slim glazing appears thin face on, at the same time it comes deeper than regular windows and doors. Again this is for retention of the performance, strength and stability of the product.

Exterior quality doors and windows come with insulated aluminium profiles and a good specification glass. Interior doors as well a screens come in two versions. One is an exterior grade door customised for interior use. Another is a dedicated interior system. These frequently come without any profile insulation as it’s not required. As well as this, interior products come single glazed too.

Virtually any type of door or window comes in a slimline version. There are presently no PVCu, timber or hybrid systems offering dimensions even close to these thinner products in aluminium.

Slimline and ultra-slim sliding doors

slimline patio doors in silver fitted to a garden room

Probably the best known and most asked-for amongst slimline doors and windows is sliding doors.

Sightlines start at around 16mm at the door mullions, therefore making these perfect for making an interior space bright, spacious and light filled. Most of these doors use the structurally bonded design.

All these doors have a frame. Hiding the frame and track gives the slimline appearance.

It’s easy to assume with slimline and ultra-slim sliding doors that the frame proportions are the same as the heavily marketed slim mullion. They’re not and especially when using the standard non-hidden installation method, you usually get thicker sightlines at the surround frame.

Importantly, slimline sliding doors come with several considerations and questions when buying. Installation, options and configurations often come more complex than conventional sliding patio doors. We’ve comprehensive information about thin-framed sliding doors, helping to buy better.

Ultra-slim bifolding doors

ultra-slim bifolding doors

When it comes to slimline bifold doors, these are typically doors with reduced dimensions at the door mullions.

Bifold doors can’t achieve the same dimensions as sliding model. We’ve put together a list of the slimmest bifolding doors brands based on their door mullion sightlines.

Other systems provide even more minimal systems using the slide and turn design. Then you’ll find premium models such as Sieger Lux and Fineline with alternative designs and even proportions.

Finally, some more advanced systems offer options for recessing the frame into the structure creating even more minimalist sightlines. However these also come with a price to match.

Thin profile floor-to-ceiling glazing and curtain walling

slimline curtain wallingfloor-to-ceiling glazing
Used residentially, creating large picture windows and incorporating slimline sliding doors

For modern homes, floor-to-ceiling glazing and curtain walling provide products spanning two or more floors.

These products utilise designs found in commercial facades. The construction involves box mullions of various sizes, assembled on site and creating large screens.

As well as providing large fixed glazing, these systems also integrate fully with sliding doors, bifolding doors and opening windows. The slimness of these profiles depends especially on several factors.

Location, wind loadings, supports and whether tied back to any floors are all essential requirements. Often, the larger the screen the thicker the mullions and frames. However, it’s common to find face widths of 50mm. Frame depths vary from 50mm up to more than 200mm for the largest facades.

Ultra-slim doors and windows

aluminium windows prices information image

Finding slimline windows for regular window replacements is often confusing for buyers. Many aluminium window brands already come with a slimline version. The sightlines you get depend on the frame and opening element combinations.

However, it’s often the case that many slimline aluminium windows easier providing thin windows for new build openings than providing slimline windows for window replacements.

In addition to standard aluminium windows, specialist installers provide high-end minimal framed ultra-slim doors and windows, specifically designed so the frame hides behind the structure and giving an all glass look.

Interior doors, windows and screens

slimline steel-look doors

For interior windows and screens, products designed for internal use frequently provide the best solution. Alternatively, exterior grade doors and windows do work inside the home in many situations.

The insulation and performance benefits of exterior windows and doors aren’t required internally. However, double glazing provides acoustic solutions when correctly chosen.

You’ll find interior ultra-slim doors and windows as well as interior products with specific systems, brands and designs. There are also near frameless versions available too. Steel-look glazing is one of the most sought after amongst these thin-framed products.

Deciding which slimline doors and windows are best

It’s important to, first of all, understand the makeup of aluminium windows and doors marketed as frameless. However, for these types of products, frameless, structural glazing and slim-framed aluminium provides the best end result.

It’s even more important to engage with a professional installer demonstrating a level of expertise and knowledge with ultra-slim windows and doors. These suppliers tend to go beyond regular window and door installations also providing a broader range of technical glass solutions, of which slimline products form just one part. Expect with these installers to find glazed links, glass balustrades, fire-resistant glazing, glass floors and other such advanced glazing systems.

These more advanced ultra-slim doors and windows are usually best designed, made and fitted by the same business. We do not recommend buying these products online. Manufacturing quality and installation by trained installers always provides the best result.


Which slimline product is right for you?

How slim your new glazing is when replacing your existing doors and windows, very much depends on your existing opening and the type of product you need.

Sliding and bifolding doors, picture windows or floor-to-ceiling glazing provides the best slimline product. Once you start adding opening elements in windows, then these naturally need a frame to work, lock securely and stay weathertight. They’re slightly thicker as a result.

Slimline products are available when replacing older products but there are compromises to be made so speaking with a specialist installer is the best place to start or getting in touch with us.

The current range of structurally bonded or slimline sliding door products work best in new openings or extensions and are the best choice of thin doors. You can set the into the structure giving a near-frameless appearance.

If bifolds are your preference there are options for minimal or frameless doors with the bare minimum of essential aluminium at the mullions, although they still need a surround frame in their design.

French doors and aluminium windows don’t generally come as ultra-slim unless you go with the high-end products, but these too need some framing in order to operate and lock correctly. A good alternative to slim windows and French doors are steel-look products but without the horizontal bars.

The look you get generally depends on the design of the window or door itself. Get in touch for more advice.

Slimline windows are widely available with frame depth starting at around 35mm for a fixed window with a thin frame, but do expect sightlines to get thicker as you add opening vents with essential mullions and transoms.

It’s possible to go with the high-end frameless windows designed to hide in the structure and this hidden fixing method is possible with some aluminium systems too.

For general slim aluminium windows, Smart Systems, Aluk, Reynaers, Stellar, Schuco and Origin start with slim lines, but steel-look windows are also worth considering here too.


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