1. Restoring wooden windows - what do you need to know?

If you live in a listed building, i.e. buildings of exceptional interest, particularly important buildings of more than special interest, or buildings that are of special interest, you cannot demolish, extend, or alter it without special permission. This includes changing its appearance or the materials it was built from. In practical terms, this means that you are not allowed, for example, to replace wooden windows and doors with metal or PVC ones, no matter how poor a state the original ones are in. However, certain steps can be taken to ensure the property is fit for purpose. This includes working services (plumbing, water/drainage, electrics) and cooling. One of the factors when adapting any property to ensure it is fit for purpose is its energy efficiency.

For an energy efficient building, the condition of the windows, doors, and facade is extremely important. This brings us to the topic of restoring old windows. Many listed buildings were built many decades, if not centuries, ago when construction techniques were different and when windows made of thin wooden and metal frames with single glazing were fitted. Today, they do not meet any of the industry standards and must be restored or replaced.

On the other hand, even when we are not dealing with a listed building, the appearance of some buildings would change completely if a different type of window was installed; in simple terms, they would look hideous, which unfortunately does happen from time to time. Many old brick houses or even wooden cabins are fitted with white PVC windows and this unholy hotchpotch of styles gives it a patchwork appearance.

2. How to choose the right firm or joiner to restore wooden windows

Restoring wooden windows requires a considerable number of decisions to be made. The first actually concerns the type of windows you have, how many there are, how they open, and the type of glass - in other words, the size of the job and the completion deadline. When you’ve decided on this, you’ll need to find a contractor. There are many offering their services, so we suggest you either contact us, since we only liaise with reputable companies and individuals, or look at their websites to check out their case studies, the comments of previous customers, and what exactly they offer.

3. What kinds of wooden windows are there and how are they restored?

3.1. All-wood windows

The oldest types of wooden windows are actually artisanal products made individually, usually by hand, from solid oak, fir, pine, or spruce and old types of glue. The only metal is the metal plates on each corner and the only opening mechanism is a simple lock. Such windows usually comprise thin frames and are single-glazed with ordinary glass. If you have such windows in your home, you’ll know that are completely inefficient from an energy point of view because the seal has usually failed so they are draughty and condensation builds up on them, leading to mould around the frames.

The other, somewhat newer, types of wooden windows are those dating back to the mid-20th century when factory production began. Some of these models are very attractive, high quality and durable, and like their ‘predecessors’ are made from the best types of wood for this purpose. It’s worth remembering that wood, as maybe the ultimate noble material, is excellent for any living space since in itself it helps regulate heat and moisture levels in the interior. Such windows should not be just cast away because, if restored in the right way and using good materials, they can last for just as long again.

3.2. Aluminium-wood composite windows

This type of window is actually ‘two-in-one’: on the outside there is an aluminium frame that is highly weather-resistant and long-lasting, while on the inside, there is a wooden frame that gives any space a warm, natural, and intimate air, meaning interior designers are only too happy to recommend it. Of course, as strong as they are, these materials are also susceptible to deterioration due to all the factors they are exposed to and so they need regular maintenance and to be restored from time to time.

3.3. Wood-fiberglass composite windows

Windows made from a combination of laminated wood and fiberglass are the latest products to hit the market. They have highly complex opening, closing, and moving mechanisms and are often connected to a smart house management system. As with aluminium-wood composite windows, the inner frame is made of wood, but the outer frame is made of fiberglass. Fiberglass is not a new material - it has been used for decades in shipbuilding, the automotive industry, and for various elements in building construction. However, only recently has it been used to make windows, thanks to innovations in manufacturing techniques and the technology of materials. Fiberglass is resistant to moisture, heat, cold and UV rays, so it is an ideal material for external features. In terms of aesthetics, it can be made to resemble wood so the window looks almost the same on both sides. Of course, after a number of years, it needs a bit of TLC, too.

4. The process of restoring or repairing wooden windows

4.1. Preparing the windows for restoration

Every restoration process has to begin with the windows being cleaned, no matter what kind of wood they are made of, how they were made, and how they operate. They can be taken out all at once or one by one, depending on how many people are working and what tools and equipment they have. When being removed, the windows should be handled with care due to the risk of any damage that cannot be seen with the naked eye and which can cause major problems later. When the casement has been removed from the frame, the glass can be taken out, although it doesn’t have to be, depending on which technique will be used to restore them and whether better glass will be fitted or not. The frames usually remain in situ, although they can also be removed if major restoration work is needed. Finally, all the window hardware is removed and then cleaned, lubricated, and put back on the window.

With the casement out of the frame, it is thoroughly cleaned to remove all the dirt and grime that has built up over the years. When this has been removed, it is time to strip off the old paint and varnish. In essence, this is the most important stage in the restoration of wooden windows. It must be done by someone who knows what they’re doing so that all the old layers of varnish and paint are removed down to the bare wood. Great care must be taken not to overdo it so as to avoid damaging the wood. There are many ways to approach this - a heat gun, a chemical paint stripper, or a paint shaver. Then the wood needs to be sanded with either an electric sander or fine sandpaper. Corners and hard-to-reach places will need to be sanded by hand.

Finally, the window will need to be cleaned once again to get rid of any sawdust left from the sanding. If you see any places that need more sanding, now is the time to sort them out before cleaning the whole window again.

4.2. Protecting, painting, or varnishing wooden windows

Once you’re down to the clean, smooth, dry bare wood, you can move onto the next stage. This part is also important because the longevity of the restored windows will depend on how well it’s done. A wood filler is applied to the clean wood to repair any cracks or other damage. The aim is to use the filler to get rid of all the problem areas. It is applied thinly and must be allowed to dry for at least 24 hours. Once dry, if needs be, more wood filler can be applied and then the window can be sanded again and then left to dry once more. Be sure to read and follow the manufacturer’s instructions to ensure the end result is as good as possible.

First, a special curative and preventive treatment against all wood parasites like insects and fungi is applied. These treatments are known as insecticides and fungicides. This is followed by a colourless primer or undercoat. If you want to leave the natural colour of the wood, you then apply a stain or varnish. If not, you can paint the windows whatever colour you have chosen with two coats usually applied. At least 24 hours must be allowed between each coat to give it time to dry properly. Otherwise, the paint will become sticky and everything will have to be stripped back again.

Finally, the windows are varnished. There is a huge range of different varnishes and countless suppliers and manufacturers, so we recommend you consult an expert about which to choose or at least ask around. Price is certainly an important factor whenever you buy anything, but bear in mind that this is a long-term investment and certainly not a job you’ll be doing on a regular basis, so choose wisely. When it comes to choosing the colour, if you decide not to leave the natural colour of the wood, make sure the one you choose fits in with the whole design concept of the exterior and interior of your home as windows are the largest and most visible elements in each room as well as the facade.

5. Improving the energy efficiency of wooden windows

The energy efficiency of your home is very important for three reasons: since you spend a large part of your time there, your health should not be put at risk in any way, maintenance costs must be such that you can afford them, and thirdly, but no less importantly, the negative impact on the environment should also be minimal.

In this sense, at the very outset, wooden windows meet two of these conditions - they are natural and therefore best for the specific microclimate and also do not have a negative environmental impact. This leaves the question of cost. By renovating and repairing old wooden windows, you’ll get new ones with the same physical characteristics and your original windows last twice as long. All that remains therefore is to make them ‘cost-friendly’ when it comes to energy efficiency.

Thanks to advances in the manufacture of paints and varnishes, there are now products available to protect and improve your windows in every sense. So your new windows, actually the old ones, will not only look better, but will also perform better. Here we are primarily talking about improving the frames and installing new glass and silicone seals. By installing the latest product - a PVC profile - in the old wooden frame, you will get a frame that is capable of incorporating thermal insulation and latest-generation low-emissivity glass, making the entire window more thermally efficient and also soundproof. A silicone caulk is the final step in the installation process and the sealant ensures the window is protected from mildew growth, water leaks, air drafts, dust, and pests. This also prevents the occurrence of thermal bridges, which are the biggest cause of heat loss.

6. Cleaning and maintaining wooden windows

When your wooden windows have been restored or repaired and look as good as new, you need to make sure you clean and maintain them on a regular basis to keep them looking that way for as long as possible and to make sure the financial outlay was worth it. Unlike aluminium and PVC, wood is a material that needs quite a lot of looking after.

This means it requires regular washing and cleaning on the outside and inside, all the while following the manufacturer’s instructions for those products used when restoring the windows. Any type of coating, paint, or varnish has a certain shelf life and must be reapplied every few years. This is particularly the case for the outside of the window, which is logical as it is exposed to the harshness of the elements. So, if you follow the manufacturer’s instructions and guidelines, your windows will continue to sparkle for years to come.