Substantial energy label jump and increased comfort for residents

New frames, windows and doors for apartment buildings Goeman Borgesiuslaan in Harderwijk

Three apartment buildings on the Goeman Borgesiuslaan in Harderwijk are getting a major facelift. Housing association Uwoon and construction company Trebbe are improving and preserving both the inside and outside of a total of 189 apartments, including insulating outer walls and roofs, modernizing entrances and redesigning unsafe storage corridors. In combination with the frames, windows and doors of Verweij Houttechniek, the homes will achieve a significant increase in energy label. In addition, the living comfort will be improved and the buildings will have a fresh and contemporary appearance. "After a model home and model grade, the real work started at the end of February," says Jan de Jong, account manager for the Northern Netherlands at Verweij Houttechniek. "Production in our factory is running at full speed so that we can deliver the first flat before the construction period."

Verweij Houttechniek designs, manufactures and assembles durable windows, doors, (move-in) frames and ancillary products, such as dormers, storerooms, hsb walls and parapet panels. "We specialize in renovation projects and work a lot for renovating contractors and property maintenance companies," says De Jong. "We value sustainability and long-term relationships, of which the collaboration with Trebbe is a great example. Following several projects in Cuijk and Ravestein, we recently started with the improvement and sustainability of the 189 apartments in Harderwijk."

On-site project recording

Verweij Houttechniek was involved in the project at an early stage, using the construction drawings to make an offer for the new frames, windows and doors, says De Jong. "The initial request was to replace all window frames including rotating parts - such as the wooden windows and doors. To identify the quality of the existing frames, any repairs and challenges, we conducted a project survey on site. This revealed that the quality of the existing window frames in the front facade was still so good that they could be retained and only the windows and doors needed to be replaced. This resulted in significant cost savings." Consideration was also given to how best to transport the frames, windows and doors. "Using a crane, the various elements are transported externally. This vertical transport is provided by the contractor. All our findings were worked out in a quotation, on the basis of which we started measuring the elements."

BCRG-certified doors

The project consists of three separate flats. For flat 1 on Goeman Borgesiuslaan, Verweij Houttechniek manufactures, delivers and assembles 308 windows and 154 window frames. "In the window frames on the balcony side there will be 77 Verweij BestLife insulated EPA rear doors. In addition, we are installing 77 Verweij BetterLife insulated front doors," says De Jong. "The rear doors are BCRG-certified panel doors. These have an insulation value of well below the standard 2.0 Ud, contributing significantly to the thermal insulation of the facade. Moreover, the insulation value may be included in the energy label calculation."

All new frames, doors and windows are delivered fully painted and glazed, he says. "Verweij Houttechniek is STIP-certified. That means that all the wood we use comes from sustainably managed forests."

Fit size windows and doors

All windows and doors in the project are measured separately. "We call this with a fancy word 'fitting' windows and doors," De Jong emphasizes. "This ensures that the new windows and doors fit exactly to the existing frames and guarantees good draught-proofing and safety." The measuring is carried out by a permanent team from Verweij Houttechniek, which also applies to the assembly. "All work is carried out at a fast pace by three experienced fitters, with one complete house being fitted with new frames, windows and doors per day. Because we are dealing here with large elements up to 3.70 x 2.54 m (wxh), a crane is used for working at height." 

Model house and trial rod

The improvement and preservation of Goeman Borgesius Avenue started at number 155, where the largest of the three flats is located. "This flat has seven floors," says De Jong. "On the fifth floor, we set up a model home. Working closely with Trebbe, we replaced two inward-turning windows on the front facade, as well as the front door. In the frame at the rear, on our advice, an existing swing window with overhead light was additionally replaced with a large swing window with injury-safe glazing." On the balcony side, solar control glazing is used. "Special here is that a corner frame is used, with a special corner coupling between the balcony door and the fixed frame. The locks are so-called senior locks, where the cylinder is placed above the door handle. This increases the ease of operation for elderly residents."

The purpose of the model home is to gain early insight into any challenges during construction, says De Jong. "But mainly to show residents what they can expect in their homes. This creates more support." Following the model home, six more homes were tackled in the same strand.

Unsafe feeling gone

Following the homes, Verweij Houttechniek is also installing new frames and windows in the new concrete elements in the plinth. "Thanks to the new plinth design, the unsafe feeling has disappeared," De Jong concludes. "In consultation with the supplier of the concrete elements, we mounted the wooden window frames in the newly delivered concrete elements on site according to a very tight schedule."