Top 5 Common UPVC Window Installation Mistakes and How to Avoid Them

Installing uPVC windows is a significant investment in a property’s energy efficiency, security, and enhanced aesthetic appeal. However, an improperly installed uPVC window can lead to a range of issues, including leaks, drafts, and compromised structural integrity. At Sternfenster, with 50 years as an industry-leading home improvement expert, we understand the importance of high quality window installation services. Which is why in this article, we will guide you through how you can ensure optimal performance and longevity, and avoid some of the most common installation mistakes.

1. Incorrect Measurement of Rough Opening Dimensions

One of the most frequent errors is misjudging the dimensions of the rough opening of a window. If the opening is too large compared to the size of the window unit, it may cause the window to shift out of alignment. This will likely lead to operational problems and the potential for leaks and water damage. On the other hand, a rough opening that is too small can result in deformation, and naturally, difficulty in fitting the window. 

Solution

The key to minimising the chances of having the incorrect opening dimensions is always to ensure that you adhere to the dimensions specified by the manufacturer. Before installing the window unit, measure the height, width, and depth at multiple points around the opening to account for any irregularities. This will ensure a perfect fit and ultimately help maintain the integrity of the window for years to come.

2. Inadequate Sealing & Insulation 

Inadequate sealing and insulation around a window can cause draughts, impacting energy efficiency and potentially leading to moisture problems in a home. 

Solution

Airtight seals are essential for the performance of a uPVC window. It is crucial to apply high-quality sealants around the window frame and to ensure that all gaps are filled. Additionally, use insulation materials that are compatible with uPVC to enhance thermal performance and to prevent both air and water from entering a property.

3. Neglecting Proper Flashing Installation

Improper installation of flashing or flashing that is absent within a window unit can lead to water infiltration. The risk of water entering through a window is that it can cause lasting water damage to the window frame, which, in time, would require replacement. It is essential to install flashing correctly to divert water away from the window.

Solution

Refer to the manufacturer’s guidelines for correct flashing installation, ensuring it overlaps correctly to direct water away from the window. Also, ensure that you use the proper techniques and high-quality materials to create a watertight seal.

4. Improper Use of Expanding Foam

Expanding foam is a great way to fill gaps efficiently and effectively. However, excessive use can put pressure on the window frame, leading to distortion or operational issues with a uPVC window.

Solution

To prevent this, use low-expansion foam that is specifically designed for window installations. Apply it sparingly to avoid adding excess pressure to the frame. Always follow the manufacturer’s recommendations for applying expanding foam. 

5. Overlooking Structural Support

Particularly in heritage buildings, the original timber window frames often provided structural support. Therefore, replacement uPVC windows require adequate lintel support to prevent structural issues, such as cracking or sagging, above the window.

Solution

Before installing a new uPVC window, ensure to assess the existing structural integrity of the building. If required, install lintels or other kinds of structural support mechanisms to hold the load above the window. This is especially crucial when replacing timber frames in older constructions.

Expert Window Installations at Sternfenster

Proper installation of uPVC windows is essential to maximise their benefits. By avoiding these common mistakes and adhering to best practices, installers can ensure that the windows perform optimally, enhancing the property value and comfort. Always follow the guidelines specified by a manufacturer, and when in doubt, seek professional advice to guarantee a successful uPVC window installation.

If you are interested in discussing an installation project or have any questions, please get in touch with a member of our expert team at Sternfenster via our online contact form or by phone at 01522 512525. To receive a competitively priced, no-obligation quote, use our online quoting tool today.