There was a time when I didn’t take installation seriously. I thought it wasn’t the most important stage. Today, my opinion has completely changed! Installation is a key stage! If installed incorrectly, even the most expensive premium-class window will perform worse than cheaper alternatives.
I want to share my years of experience. I’ve been working with aluminum window systems for over 15 years. During this time, I’ve tried different techniques and materials. This article is for those planning to build their own home. You’ll learn how aluminum systems should be properly installed and be able to assess the quality of the installers’ work. I believe even professionals will find something new and useful here. But let’s take it step by step!
We’ll cover two installation options: in-wall and offset mounting. We’ll also talk about the installation of frame products — windows, doors, sliding systems. In addition, I’ll explain the specifics of installing post-and-beam façade systems.
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What is special about installing frame window‑door systems?
Frame systems are fastened around the perimeter. The fastening point spacing must be no more than 600 mm. The spacing from each corner should be no more than 150 mm. Since a large weight rolls along the bottom frame, it is extremely important to install it perfectly level without dips.
What fastening options are there for installation into the opening?
The first option is using a mounting plate. It bends easily, which makes it simple to level the frame during installation. The challenge comes during the foam sealing stage. This type of plate lacks rigidity, so the frame may bulge when the foam expands. This creates an inward bend in the frame — like an hourglass. If the bend goes the other way, forming a “barrel” shape, it usually means the frame was overtightened during installation.
There’s a more rigid 2 mm thick plate available. It’s sold in rolls and must be cut and bent in advance. That’s where extra complications arise. A regular plate can be bent by hand, but this one requires special tools and precise measurements. You can’t adjust it on-site during installation. If you try to do so, the plate may rip the screws out of the aluminum. That’s why working with it involves several steps: you first install the window into the opening, mark the fastening points, take measurements, and only then bend the plate accordingly. After that, the plates must be screwed to the window and inserted into the opening along with them. As you can see, it’s not the easiest process!
I prefer installation using frame anchors. They allow the aluminum structure to be fixed directly through the frame. I used to work with standard yellow Chinese anchors, but I’ve stopped using them. These anchors are not universal and perform poorly in gas concrete, foam blocks, and ceramic blocks. They tend to spin and can be pulled out by hand — not the most reliable fastening method. Additionally, the visible anchor head doesn’t look good, so you have to plan for decorative caps in visible areas.
Eventually, we switched to Blaugelb turbo screws. This is German technology: the screws have a tapered thread towards the tip, which reduces the screwing torque. This allows them to grip better in porous materials. Turbo screws provide solid frame-to-opening fixation using wedges. As a result, the structure doesn’t bend in any direction during the foam application stage. Turbo screws are 2–3 times more expensive than standard anchors, but the result is worth it. You could say this is a universal fastening solution. My installation team uses turbo screws most often.
We also install sliding systems using turbo screws. Sliding systems have a plastic track around the perimeter. We remove these tracks, take out the sashes, and level the frame. Under the track, we place one turbo screw in both the inner and outer chambers. Installing the bottom frame of a sliding system is a critical task. As I mentioned earlier, the fastening step should be more frequent. The sashes, which are quite heavy, move along the bottom frame. Therefore, it must be installed perfectly level. There can be no unevenness — otherwise, the system won’t function properly.
When installing windows on a parapet, I used to use the regular support profile from Alutech. But with it, a cold bridge appears at the joint and condensate forms. Later we switched to warm support profiles such as those from Meesenburg or Compacfoam.
If you need floor-to-ceiling panoramic window installation, it’s often necessary to raise the window above the concrete floor by 150 mm to 300 mm. Building parapets is not the best solution — they can interfere with installation. Moreover, it’s much better when a heavy window structure is mounted directly into the concrete floor rather than into a parapet made of another construction material. In this case, we install a tall warm support profile underneath. Most often, we use Compacfoam — it’s easier to mill the required height and cross-section level in it.
For a sliding system the distance from the floor can be even greater. Previously we used fiberglass tubes on threaded rods to install such a structure. The tubes allowed us to set the required height and adjust the frame perfectly level.
We currently use adjustable HILST supports for installing sliding systems. Here’s how it works: the frame is placed on top of a 30 mm support profile, followed by the HILST support. The support profile is necessary to install galvanized bottom flashings and to allow proper waterproofing connections.
The supports have proven to be very effective! They are easy to adjust and securely bear the load. This allows for perfect leveling of the structure, ensuring no sagging will occur. Then, we install Penoplex insulation between the supports, and mounting foam is applied. On both sides, we attach galvanized flashing, which is fastened to the concrete with sealant and nails.
Features of offset installation
There are several quality installation options for this type of setup. The first option is using an external warm profile such as Trioterm or Compacfoam. A frame is created around the window from this material, which is fastened to the outer wall with turbo screws. The depth of the extension can vary. Additional support legs are added under high-load areas to increase load-bearing capacity.
The frame made from this material serves both as structural support and thermal insulation. The window is screwed directly into the Trioterm with turbo screws, then filled with foam and sealed. We rarely use this installation method on projects because the material is too expensive.
There is a more affordable yet equally high-quality method that my team uses most often. It’s installation using the German Knelsen external mounting system. The set includes: bottom load-bearing brackets with gussets and special extension plates.
Unlike the standard mounting plate I mentioned earlier, Knelsen is much more rigid. It has a special U-shaped profile with a thickness of 3 mm. This hardware is specifically designed for external window installation.
We create a frame around the window from foam board (penoplex). It acts as an insulating material and does not carry the structural load.
How to install a sliding system with an offset?
For a two‑rail frame you can use Knelsen brackets in the same way as described above. If the frame is three‑rail and heavier, we weld a steel sub‑frame made of angles and fix it to the brackets, and only then mount the sliding system.
Installing a façade stick curtain‑wall system
In a mullion-transom façade system, only the top and bottom of the vertical mullion are fixed. The horizontal transoms are not mounted to the wall opening; they are attached to the mullions. Accordingly, the main load is distributed to the bottom fasteners. The top bracket in a façade system only bears wind loads.
When installing the façade system into an opening, I use Alutech aluminum mounting plates. The mullion is fixed at the top and bottom with anchors. If possible, the bottom part is extended and secured with bolts. If not, above the transom, we fasten with stainless sleeves and decorative washers, tightening with a screw. This method is suitable for heavy insulated glass units. If the glass unit is not heavy, 4–6 screws are driven in from the gasket side. This is an acceptable system solution.
Next, we create a sandwich joint around the perimeter. Then the structure is foamed. The gap between the transom and the floor is filled with insulation, usually full-depth penoplex.
We installed an 8.2 m‑high stained glass window weighing 7.5 tonnes in offset. For this we specially designed a huge bracket which was fixed to the reinforced concrete columns of the building. You can see how we did it in the video.
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How do we do hydro‑ and vapour‑proofing?
According to GOST standards, a vapor-permeable waterproofing layer must be applied on the outside. It blocks water from the outside while allowing vapor from inside the building to escape. On the inside, a vapor barrier layer is applied to prevent indoor moisture from entering the installation joint.
There are two main ways to create vapor and moisture insulation: using sealants or tapes.
Most installers typically use standard cheap tapes. My team has long stopped using them. These tapes don’t adhere well and tend to trap moisture. They are often pushed out after foam expansion. As a result, the tapes hang loose around the window perimeter, and finishers usually end up tearing them off. In my experience, no one has managed to attach them properly.
There is a more expensive and higher‑quality option: German tapes from Meesenburg. These tapes have a wide working temperature range, are self‑adhesive and can withstand high loads. They are easy to apply and adhere perfectly.
But on my projects I prefer to use sealants. This method effectively holds moisture and the mounting seam maintains its quality for many years. Inside we use Stiz B, and outside Stiz A.
However, these sealants do not hold the bottom node, where a large amount of water accumulates. Therefore, at the bottom we additionally use Kortlinger 791. If you do not have such a sealant yet, I advise contractors to create one for themselves. This will help perform installation even more effectively and with higher quality. I hope the article was useful!
