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Refurbish Wooden Windows Instead Of Replacing Them

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Refurbish Wooden Windows Instead Of Replacing Them
Refurbish Wooden Windows Instead Of Replacing Them

Video: Refurbish Wooden Windows Instead Of Replacing Them

Video: Refurbish Wooden Windows Instead Of Replacing Them
Video: Wood Window Restoration: This Process Brings Life Back into Old House Sashes (2020) 2023, November

What to do with heavily weathered wooden windows? Is the exchange really the only way? With a wood repair system, an inexpensive and sustainable repair is possible with the means of the painting and varnishing trade.

Author: Susanne Sachsenmaier-Wahl I Photos: Caparol

Even if the plastic window has already replaced many (old) wooden windows, there are still building owners who deliberately chose wooden windows. "The inventory of wooden windows in Germany is currently, depending on the source, only a maximum of 17 percent," says Bernhard Linck, Product Manager Lacquers and Glazes at Caparol. “Despite the growing awareness of sustainability and the environment, economic considerations are clearly in the foreground. Here the wooden window will always be the loser. Nevertheless, the wooden window will continue to exist in the future. It won't die out. The numbers for the current wooden window inventory have remained constant in the last few years.”Be it because of the look or because the decision was made in favor of a renewable raw material,the wooden window needs regular maintenance in the form of a coat of paint in order to give the owner long-lasting pleasure. If this maintenance is neglected, it can quickly happen that the wood is so badly damaged that a simple coat of paint is no longer sufficient. But even then the painter can be the rescuer in need and prevent further wooden windows from being replaced by those made of plastic or aluminum - and thus preserving valuable contract areas.that other wooden windows are replaced by plastic or aluminum windows - and so valuable order areas are preserved.that other wooden windows are replaced by plastic or aluminum windows - and so valuable order areas are preserved.

Extremely stressed areas

As a rule, it is the horizontal components of windows and balcony doors that show significant damage after a few years of weathering. “Rainwater not only hits these horizontal surfaces directly, but also runs off from the window surface and partly from the facade surface above it via these parts of the window sash and frame. These areas (e.g. weatherboard on the sash and lower window frame above the window sill) are the most heavily used parts of a window and are damaged first of all,”explains Bernhard Linck. If it is also less weather-resistant wood, such as spruce wood, then - if the complete window replacement is not an issue - there is often only one option at first glance:Have the horizontal window components replaced by a wood specialist. But there is another way. With the help of a wooden strip, the appropriate paints and a cover strip made of aluminum, the painter can renovate wooden windows professionally, relatively inexpensively and above all sustainably.

Away with the ailing wood

If the horizontal components are very badly weathered, a clean component edge can no longer be modeled using a filler. Therefore, in the first step, the crossbar should be freed from all wood that is no longer strong and stable. The weathered surface can be separated cleanly with an oscillating sawing tool. Wooden strips with a triangular cross section are available from specialist wood dealers. These can be used to produce a straight component edge on the crossbar. The triangular cross-section ensures that the edge also has the required drainage tendency.

To ensure good adhesion, treat both the shortened crossbar and the wooden bar with a suitable primer, e.g. B. a two-component primer based on epoxy resin. On the one hand, this impregnates the raw wood; on the other hand, it has a wood-consolidating effect. After a flash off time of

Approx. 20 minutes - the primer must never be wet anymore - a wood repair compound, also consisting of two components, is placed on the crossbar and wooden strip. It is the connecting element between the two wooden parts. As soon as the bar has been put on, align it with a spirit level. Then you let the wood repair compound dry. If the bar should be wider than the existing cross bar, it does not matter. The supernatant is simply ground flat after drying.

Painting structure

If the skirting or the window is made of spruce wood, the raw wooden surfaces should be properly protected from blue stain with a wood impregnation primer before the actual painting.

Now you can paint with suitable coating materials. Glazing can be used, for example, with an aromatic-free alkyd resin glaze or a water-thinnable PU glaze. For opaque coatings, there is a choice of aqueous PU paints or ventilating paints. Glazed wooden windows, in particular, are often so badly affected by the weather that a new glaze coating alone cannot achieve a visually satisfactory result. “Simply glazing over it is no longer enough,” says Bernhard Linck. “In the case of a window that has been damaged in this way, it must be considered for economic reasons whether the lightening or graining technique is the better solution. This would also lead to longer maintenance intervals, since covering coatings generally last longer than glazes.“The priming is done in a color that matches the wood. Then you glaze the window twice. The brush stroke creates the impression of a wood grain.

Double protection

With a standard window renovation, the work would now be finished. The window looks attractive again, has a drip edge with a corresponding incline and is protected from the weather for now.

As mentioned at the beginning, the critical areas on a window are the horizontal sash and frame parts. All of the rainwater runs off the panes over these narrow component surfaces. The weather exposure is many times higher in these areas and as a result the coating degrades much earlier. So what could be more obvious than to protect these areas particularly well and thereby make them more durable? If you look at modern window constructions, they often already show the solution: The horizontal components are protected by an aluminum cover strip.

Why shouldn't you retrofit an old window in a very simple but extremely effective way?

Simple, but effective

A system consisting of cover strips, fastening clips and elastic rubber caps in various widths and colors is offered specifically for retrofitting existing windows.

For the correct length of the cover strip, take the dimension of the weatherboard on the pane and pull two five millimeters from it, making a total of one centimeter for the rubber plugs that are still to be attached. The cutting is done with a miter or chop saw. The rubber plugs are placed on the right-angled ends. They later ensure the tight connection to the vertical wooden components, even if the wood should move due to temperature changes.

The aluminum strips are attached using sturdy plastic clips. This means that the strips for a maintenance coat of the window can be removed and replaced at any time. The clips are screwed onto the wooden frame. A spacer on the underside of the clips automatically positions them correctly on the component edge. The spacing of the clips and thus their number are specified by the manufacturer of the cover strip. The appropriately sawn-off cover strip, which is fitted with rubber caps, is attached to the pane and snapped into the clips with slight pressure on its front edge.

Finally, the connection between the glass and the window frame is sprayed out with an elastic seal and pulled off with a joint smoother.

Durable result

At a window renovated in this way, the rainwater runs from the pane over the bar, which is inclined by 15 degrees, to the edge of the ledge, which protrudes eight millimeters. Here it drips in front of the wooden surface, which means that the weatherboard is significantly less stressed. The customer can look forward to a window that not only looks attractive, but is also much more durable. "This measure extends the renovation intervals by two to three times," clarifies Bernhard Linck. “Depending on the weather, renovation intervals of ten to 15 years can be possible on the north and east sides. Six to eight years on the south-west, so-called firedamp pages.”At first glance, this may reduce the painter's orders. Nevertheless, the bottom line also benefits:first, of course, from a larger order and, in the long term, from a satisfied customer. Maintenance coats are still necessary (albeit at longer intervals) and are retained by the painter, since the completely renovated wooden window does not have to give way to a plastic or aluminum window. A win for both sides.

Nevertheless, this window renovation naturally has its limits. "Of course you can't retrofit all windows like this," admits Bernhard Linck. "For lattice windows or generally in listed buildings, this is forbidden for reasons of a historically authentic appearance." But these windows are preserved as coating surfaces anyway - because here the plastic window definitely does not compete.

More photos for window


The crossbar is freed from the weathered wood with an oscillating sawing tool.


aluminum bar, sawn to the correct length, is pressed onto the clips.

The rubber caps on the ends of the aluminum bar nestle firmly against the wood and absorb temperature-dependent changes in length.

Finally, the area between the glass pane and the frame is sealed elastically and removed with a smoothing knife.

A wooden strip with a triangular cross-section can be

used to produce a straight component edge with the required drainage inclination.

After priming with a primer, a wood repair compound is applied to both the crossbar and the wooden bar.

The wooden strip is pressed onto the cross bar. The wood repair compound connects both parts firmly and without gaps.

The front edge is leveled.

If the bar is a bit too wide, it is sanded flat after drying.

If it is a spruce wood strip, it should be impregnated with a blue stain before coating.

For glaze windows that are exposed to severe weathering, we recommend the texturing technique, consisting of an opaque primer and a glaze.

Fastening clips are screwed onto the finished coated window. A spacer on the underside positions them appropriately on the component edge.


Caparol supplies the "Capadur Repair" wood repair system, consisting of a two-component wood repair compound and the associated primer, end grain protection and window glass sealant in three colors. The aluminum profiles for covering the critical window areas are available from Renova 1–2–3.



Bernhard Linck, Product Manager Lacquers and Glazes at Caparol

This measure extends the

renovation intervals for wooden windows by two to three times