How to Avoid Having Swelling Doors During the Winter

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Sash Windows Refurbish specializes in providing repair and restoration services for wooden windows and doors in the UK, as well as various types of carpentry. During the process of fulfilling orders, we utilize a range of tools and paints, including saws, sprays, primers, resins, and adhesives. With more than 20 years of experience in carpentry, we have tested and used various brands and types of work tools, making us well-equipped to offer helpful advice on selecting the right tools and paints for your needs. Read more ...

What Makes Doors Expand?

Doors may swell due to various environmental factors and conditions. Swelling in doors is typically a result of changes in moisture content or exposure to extreme weather conditions. Here are some common causes of door swelling:

  1. Moisture Absorption:
  • Humidity: Wooden doors are particularly susceptible to changes in humidity. When the air is humid, wood tends to absorb moisture, causing it to expand. This expansion can lead to swelling in the door, making it difficult to close or open smoothly.
  • Direct Contact with Water: If a door is exposed to water directly, either through rain or spills, the wood can absorb the water and swell. This is especially true for exterior doors that may be subjected to rain or high humidity levels.
  1. Poor Sealing or Finishing:
  • Lack of Sealing: If a door is not properly sealed or finished, it becomes more vulnerable to moisture absorption. Sealing the door with an appropriate finish helps to create a barrier that prevents excessive moisture from penetrating the wood.
  • Damaged Sealants or Finishes: Over time, the sealants or finishes on a door may degrade or become damaged. When this happens, the protective layer is compromised, and the door becomes more susceptible to moisture, leading to swelling.
  1. Temperature Fluctuations:
  • Extreme Temperatures: Rapid or extreme changes in temperature can also contribute to door swelling. For instance, if a door is exposed to intense heat, the wood may expand. Subsequently, when the temperature drops, the wood may contract, but if the door is unable to contract due to various reasons, it can result in swelling.
  1. Improper Installation:
  • Misalignment: If a door is not installed properly or if it is not aligned correctly within its frame, it may be more prone to swelling. Misalignment can create gaps or friction between the door and the frame, making it difficult to open or close smoothly.
  1. Type of Wood:
  • Wood Species: Different wood species have varying degrees of susceptibility to moisture. Some types of wood are more prone to swelling than others. Choosing a wood species with natural resistance to moisture or using engineered wood products designed to minimize swelling can be beneficial.

How to Prevent the Swelling of Your Door

Dealing with a swollen door can be a nuisance and even pose safety risks if not addressed. Fortunately, there are practical steps you can take to prevent and remedy this issue. Understanding the root causes is crucial before implementing corrective measures. Swelling can result from factors such as high humidity, direct water exposure, poor sealing, temperature fluctuations, and more.

  1. Identify the Cause:
  • Before addressing the swelling, pinpoint the underlying cause. Examine whether it’s triggered by high humidity, direct water exposure, poor sealing, temperature fluctuations, or a combination of factors.
  1. Adjust Humidity Levels:
  • Combat high indoor humidity by using a dehumidifier, especially during wet seasons. Maintaining humidity levels between 30 and 50 percent helps reduce moisture content in the air, preventing the door from absorbing excess moisture and swelling.
  1. Ensure Proper Sealing:
  • Inspect the door for gaps or cracks in the sealing. Reapply or replace weather stripping and door sweeps to create a tight seal, acting as a barrier against moisture infiltration.
  1. Reapply Finishes or Sealants:
  • If the door’s finish or sealant is worn or damaged, consider reapplying or replacing it. This protective layer shields the wood from moisture and temperature changes, minimizing the likelihood of swelling.
  1. Repair Leaks and Redirect Water:
  • Promptly address water exposure due to leaks or poor drainage. Repair any roof or wall leaks, and ensure proper water redirection using gutters and downspouts to protect the door from direct water contact.
  1. Control Indoor Climate:
  • Maintain a consistent indoor temperature to avoid rapid fluctuations that contribute to door swelling. Use heating and cooling systems to regulate the climate, preventing adverse effects on the door.
  1. Sand and Plane the Door:
  • If the door has already swollen, gradually sand or plane it to reduce its size. Focus on areas where the door binds or sticks, checking the fit frequently to prevent overcorrection.
  1. Check Hinges and Hardware:
  • Examine hinges and hardware for proper condition. Tighten loose screws and adjust hinges as needed. Well-aligned hinges contribute to smooth door operation and help prevent further swelling.
  1. Consider Using Anti-Swelling Products:
  1. Explore anti-swell coatings or sealers designed to minimize moisture effects on wood. Applying these products adds an extra layer of protection to the door.
  1. Consult a Professional:
  • If uncertainty persists or if efforts prove ineffective, seek guidance from a professional carpenter or door specialist. Sash Window Refurbish expertise can guide the best course of action based on the specific characteristics of your door.

Taking proactive measures is crucial to control moisture, maintain proper sealing, and promptly address issues. Regular maintenance and attention to environmental conditions will enhance the longevity and functionality of your doors.

Beyond these general steps, there are additional measures you can take to prevent door swelling:

  • Inspect Your Door Frame and Hinges: Check for signs of excessive moisture or loose screws. Tighten them to prevent warping and ensure a secure fit.
  • Check Drainage Around the Perimeter of the House: Poor drainage can lead to dampness, causing doors to swell. Clear clogged gutters and downspouts to prevent water penetration.
  • Maintain a Consistent Temperature Inside The Home: Avoid drastic temperature changes by keeping indoor temperatures consistent. This helps protect doors from swelling during the colder months.

By incorporating these additional steps, you can fortify your doors against swelling, ensuring they remain functional and aesthetically pleasing throughout changing seasons.

How to Inspect the Moisture in Your Door

Regularly inspecting your door for moisture is vital to prevent issues like mould growth and wood rot. Check both the exterior and interior for signs of discolouration, warping, or peeling paint. Run your hand along the door’s surfaces, paying attention to dampness or soft spots. Inspect weather stripping, seals, and caulking for damage, replacing as needed.

Ensure the door sweep at the bottom is intact to prevent drafts and moisture entry. Invest in a moisture meter to quantitatively assess moisture content, probing potential problem areas. Promptly address visible mould or mildew and monitor condensation on the door surfaces. Examine nearby walls, floors, and ceilings for water damage signs.

If moisture-related problems are detected, take immediate action—repair leaks, replace damaged seals, or enhance ventilation. Moisture indoors can lead to peeling paint, mould, and bubbled finishes. Regular checks, including humidity levels, are crucial.

A moisture meter helps quantify moisture content; levels exceeding 10% require immediate attention. Swift problem resolution ensures your door remains resilient, maintaining your home’s structural integrity. If standing water or puddles appear, consult a moisture repair specialist promptly.

Keys to Weatherproofing

Ensuring a thorough defence against winter-related challenges necessitates a holistic strategy for weatherproofing your residence. From bolstering insulation to closing gaps, dedicating effort to safeguarding your home from the harsh elements is paramount.

As the winter season approaches, it becomes imperative to revisit the fundamentals of securing your home against the adversities of weather. The core of weatherproofing involves fending off the chill and moisture, simultaneously addressing potential sources of leaks that could inflate heating expenses.

Effectively sealing cracks around windows and doors, maintaining clear gutters and downspouts, and repairing any wall perforations are crucial steps in ensuring that the winter air remains outside.

Preserving the integrity of insulation, safeguarding it from dampness or damage, not only enhances warmth during winter but also contributes to year-round energy cost savings. Investing time in meticulous weatherproofing now proves to be a preventive measure that saves you from future inconveniences, guaranteeing a cosy winter season for all occupants.


Will my swollen door return to normal after winter?

In many cases, doors will return to their normal size as the humidity decreases. However, prompt action to address the swelling can prevent lasting damage.

Can Painting a Door Prevent Swelling?

Painting a door can provide a protective layer, but it’s not a foolproof solution. Combining painting with other preventive measures is recommended for optimal results.

What can I do if my door won’t close in the winter?

If your door refuses to close due to swelling, consider sanding or planing the edges for a temporary fix. Long-term solutions involve addressing the root causes, such as humidity control and proper sealing.

Do doors swell in winter or summer?

Doors typically swell more in humid conditions, which are often associated with summer. However, changes in temperature and humidity can affect wooden doors in both winter and summer.

How to open swollen wooden door?

To open a swollen wooden door, try easing it by sanding or planing the affected areas. You can also use a lubricant like paraffin wax on the edges to reduce friction.

How to stop a wooden door from swelling?

To prevent a wooden door from swelling, consider applying a sealant or varnish to protect the wood from moisture. Maintaining a consistent indoor humidity level and avoiding direct exposure to extreme weather conditions can also help prevent swelling.

About the author

Glen Ramsey, who presently holds the positions of customer support and content manager, is a cherished member of the Sash Window Refurbish team. He is in a unique position to provide advice on all questions pertaining to the renovation of historic windows because he has a wealth of experience in all elements of window renovation, dealing with clients regularly and assisting them in choosing the best window-related course of action. He oversees the creation of information for all of our platforms in his capacity as content manager, including web content and other materials. Glen has witnessed the whole gamut of Sash Window Refurbish's window restoration activities, from our work on significant listed Georgian homes to a wide variety of smaller-scale private residential projects.


My technician Andrew replaced all my sash windows that had rotten sills. Accessing the rotten sills was not an easy task. He explained to me what needed to be done in order to fix the problem. He is a great person and I’m happy that he was the one who did the job. He is reliable, tidy, friendly and very professional. I highly recommend him.



I hired Andrew and Alex a while back to repair my damaged sash windows. They were was very considerate and very patient as he did his job. A few days ago, I had another problem with one of my sash lock keys and I called him again to come and fix the problem. I’m very impressed that Liam responded quickly and he not only fixed the problem but he also gave me a spare key. What a great after sales service!

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Alex did a great job in fixing windows in our terraced house. The windows were broken, frames damaged and the wood was also rotten. Alex's job was high quality and he did it pretty fast. I was also very impressed that he was considerate of my son’s asthma condition and maintained cleanliness. Top work.



Andrew just recently replaced three sash windows in my Edwardian house. He also repaired and replaced some sills and draught proofed three windows. In addition to that, he also did some carpentry work. What I like the most about Liam is that he did a clean job. He is very professional and always updated me about the timescales and costs. He also did his job with minimal disruptions. I highly recommend him.

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