CRP or galvanized? Which one do you choose?


First, we will give a brief introduction of CRP and state its advantages. Then, in the rest of the article, we will discuss the current conditions of using galvanized, and finally we will leave the choice of galvanized or CRP to you.

CRP stands for Composite Reinforced Plastic, it means composite reinforced plastic and is made of compressed fiberglass, which its manufacturers believe is a good alternative to galvanized profile.

CRP profile

It is made in different sizes and cross-sections, the dimensions of which follow the dimensions of galvanizing and are mostly specific to the desired profiles in the UPVC industry. And each cross-section has different uses, among which we can mention CRP inside the frame, mullion, window sash and door sash and even waiting frame.


Advantages of CRP frame over steel frame

Waiting frame or frame frame is a frame that determines the range of door and window and is generally (not always) placed as the main frame and base for the window inside and outside the wall. Using CRP in this frame has the following advantages:

  • Approximately 50% price reduction compared to the iron frame
  • Approximately 30% reduction in weight compared to the iron frame
  • No need to paint, rust-proof and no rot
  • Easy to form curved and arched – more insulation than iron
  • The same coefficient of contraction and expansion between the subframe and the double-glazed window

(The advantages we mentioned above are the points of view of CRP producers. Of course, the approval or disapproval of this matter is left to the reader of the article)

Using CRP inside the double-glazed window

The CRP profile is similar to the Persian Upvc profile, and they are connected to each other using a profile welding machine, and even the best time to use it is that because they are produced in the form of six-meter branches, they are placed inside the UPVC profile compartment before cutting. take and cut at the same time as cutting the uPVC profile.

Advantages of CRP compared to galvanized:

• After placing the CRP inside the UPVC profile, both profiles are cut at the same time.
• Reinforcement profile (CRP) is welded at the same time as the profile, so the welded part becomes strong and strong.
• Due to the thickness of the CRP profile, which adds about 1.2 cm to the UPVC profile, CRP manufacturers claim that it increases the profile’s insulation.
• Due to the components of the CRP profile, the issue of rust and decay is eliminated, unlike non-standard galvanized structures. Of course, you should know that galvanizing and the galvanized layer, which is made of zinc, should not rust in scientific reality, but since some galvanizing manufacturers use galvanized sheets with improper coating, the question of rusting arises in galvanizing.
• CRP is fireproof and inflexible against cold and heat.
• Its skeleton is more compatible with the structure of upvc double-glazed doors and windows.
• It is possible to use CRP profile for form and mullion in U shape and square box.
• • The CRP profile eliminates the need for double-glazed window manufacturers and consumers to use screws.
When using the CRP profile, the speed of work reaches at least 2 times, and the elegance and power in production increases.
• We already mentioned that the CRP profile is 6 meters long and it is cut and welded at the same time as the profile.
(Keep in mind that the benefits we mentioned above are the points of view of CRP manufacturers. Our suggestion to the dear readers of the article is to do more research on the above content)




The key and important role of the standard galvanization in the uPVC window is that when it is placed inside the uPVC profile housing, it acts as a washer or holder and keeps the screws that pass through the profile as a result of connecting the hinge, connector and mullion fastener. For this reason, after a lot of opening and closing and the pressure caused by the weight of the window sash and glass on the hinges, the galvanization inside the window does not allow the screw to move and keeps it in place, and as a result, increases the life of the window.

Advantages of galvanized sheet

  1. Long service life of galvanized sheets (about 20 to 30 years)
  2. High hardness and strength of galvanized sheets and its invulnerability
  3. High resistance to rust, corrosion and friction
  4. Durability and durability of the cover
  5. Easy inspection and detection of galvanized sheet

Review the use of galvanized or crp

In recent years, there have been many disagreements between experts regarding the evaluation criteria and the use of galvanized in double-glazed windows, and in the meantime, some profiteers have also used this muddy water for their own benefit, including by reducing the thickness of galvanized. By removing it in the opening with non-scientific and technical arguments, unifying its design, etc. In the following, we will try to answer this issue and these disagreements:


Why should we use galvanized?

The use of galvanization for strengthening and also for bearing dynamic and static loads (including external loads and direct loads) to the window is one of the undeniable requirements of the double-glazed window system, and it is claimed that it can be used for a specific profile, or in specific conditions. He did not use galvanized, it is baseless and has no technical, scientific or standard support, and there is no such issue in any of the standards developed either in Iran or in other countries. We must not forget that the UPVC profile is not able to withstand any weight or any load placed on it, and if galvanized is not used, the possibility of breaking, deforming, changing the shape or losing the sealing will be the simplest possibilities. .

Of course, recently, some German companies have released new profiles that do not require galvanizing. Regarding these profiles, which are known as Fibre-reinforced, it should be said that these profiles have a special technology and have an upvc profile top that acts as insulation, while the main structure of the profile and the constituent columns The chambers are made of very hard polymer. In addition, due to the very high price of these products, this system has not actually entered Iran, and if it does, it will not be able to compete with conventional types of upvc profiles in terms of price.

Is there an alternative to galvanized windows?

But regarding this question, is it possible to use another example or an alternative product instead of galvanizing in the usual profiles?
Despite the advantages mentioned above for CRP, the use of this product has not yet been approved by any of the legal authorities, and in addition, none of the prominent manufacturers of the country’s profiles offer a guarantee for the UPVC door and window product. Issue a quality written letter that the assembly work has used CRP instead of galvanized.
This means that CRP profile producers could not provide the necessary standards for UPVC profile producers, so it is not recommended to use these profiles instead of reinforced galvanization.


In the next article, we will examine the selection criteria for galvanizing and the static and dynamic loads on a window.

With the above information, it seems that the use of CRP with all the advantages that the manufacturers state, is practically not standard and it is strongly recommended to use galvanized.

Picture of علی حاجی جعفری

علی حاجی جعفری

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