The wooden window: environmentally-friendly and durable

The traditional wooden window, casement or sash, with 4, 6 or 12 panes, contributes to the character of an old building. But when the time comes to repair or change wooden windows, we must consider if those made of aluminium or PVC are a wise alternative. Actually, the answer is no for several reasons.

— by François Varin, architect. Collaboration: Continuité Magazine.

6 pane wooden windowPeople are increasingly concerned about making “greener” decisions. In this regard, the wooden window should become the popular choice, since this material, in addition to being durable, is environmentally-friendly. The same cannot be said about vinyl (or PVC), which is made of polluting chemical components that can hardly be conciliated with the principles of environmental protection and sustainable development.

Of course, windows must first and foremost be well designed, airtight and functional. As long as they are made by qualified carpenters, wooden windows are quality products. And contrary to popular belief, a PVC window costs as much as a wooden window of matching quality.

In addition, wood has an insulating capability that is superior to PVC or aluminium – the latter in fact offers no resistance to heat loss. Traditional windows are made of an inside window and an outside storm window. This assembly procures superior insulation with two layers of wood (i.e. the frames) and an insulating air space between the window and the storm window. It has been proven that traditional windows are as efficient as a singleframe thermal glass window. The latter is exposed to extreme temperatures from the outside and the inside and therefore ages rapidly.

Multi-paned wooden windowsThe window is the weak link in a building’s envelopeProtective covering elements of a building.. Regardless of the material from which it is made, heat will escape through its frame and its glass panes. Air space between the panes will significantly reduce this problem. Heat loss in the case of single-glaze windows is 45% more than in the case of double-glaze thermo pane windows that benefit from 1.25 to 1.88 cm (½” to ¾”) of air space between the two panes of glass. It is pretty much the same for a window and storm window assembly.

In any house, the number and dimensions of the windows are an important factor for the quality of life of its residents. Windows let natural light come in our homes and this light is essential to our well-being. We must however accept these facts: heat loss through windows is inevitable and thermal insulation properties of windows will never be as good as those of a wall.

Home with traditional wooden windowsChange or repair?

Considering these facts, think twice before deciding to change your windows. This option should only be considered if the existing windows are seriously deteriorated and no longer provide adequate insulation. If the window and storm window assembly is in fairly good shape, repairing it would be more advantageous because new windows will not significantly improve the energy efficiency of the house.

Original wooden windows can be repaired without spending enormous amounts of money. Often, only their secondary parts need repairs: the lower rail, the sill, the lower part of the frame. The structural frame and the movable parts are rarely deteriorated.

It is quite possible to restore a wooden window’s original qualities. To do so, you first need to replace the parts that are rotten or deteriorated, then caulk the areas where the frame is in contact with the building wall, repair the putty around the glass panes and apply weatherstripping on the inside, in the appropriate sections according to the movement of the movable parts.

House with traditional wooden windowsWooden windows can also be stripped. Once the wood is exposed, it can be protected against rot with a sealer over which a base coat is applied, followed by two coats of paint. This is also the method to repair the parts where paint is flaking or cracking or looks like chalk. This will ensure that water and humidity cannot penetrate the wood and start a rotting process.

Why replace windows when simple repair work can restore their original condition for less money? Repair and conserve is much more in keeping with sustainable development.

If replacing the windows is the only solution, careful planning is essential, since there might be major consequences for the curb appeal of the house. The important thing is to respect the original materials, dimensions, type of windows (casement or sash) and the colour.

Wooden windows in the atticWood, beautiful and durable

Wooden windows offer several possibilities where design and assembly details are concerned. A qualified carpenter can repair deteriorated windows or replace them, if need be, with windows of the same type and with the same dimensions and look.

The standard aluminium window will not readily fit in the original openings; only a custom-made product will allow the maintenance of the windows’ original dimensions. Reproducing some of the original details of the windows will be costly or impossible to achieve, in addition to the fact that metal is a cold transferring agent and does not provide an adequate thermal coefficient.

Traditional home with traditional wooden windowsSince vinyl windows have various sections and are pre-assembled, it will be difficult to reproduce the original windows’ characteristics without a sizeable investment. Because a vinyl window’s dimensions are standardized, it will be installed inside the existing wooden window frame, thereby reducing the window’s size and decreasing the natural lighting of the room. The space between the new window’s posts and upper rail will need to be filled and covered with PVC panels that have no moulding, thereby changing the look of the window and decreasing natural lighting.

Though vinyl is a lesser cold transferring agent than aluminium, such plastic products will deteriorate over the years and cannot be repaired.

Indeed, a window’s performance must be evaluated over the long term. As long as they are properly maintained, wooden windows offer a better value for your money when durability and thermal qualities are considered. The cellular structure of wood makes it a poor heat transferring agent and it is therefore known as an effective material for thermal and acoustic insulation. Furthermore, compared to aluminium or PVC, wood reacts to a lesser degree to freeze-thaw cycles. Aluminium and PVC windows therefore need re-caulkingFilling material or filling the joints of an opening to make them air-tight. more frequently.

It is true that wooden windows require meticulous maintenance to maximize their useful life. But the new and more effective stains and paints make this task easier. Overall, wooden windows remain an unbeatable environmentally-friendly and aesthetic choice.