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Your DIY Guide to Draught Proofing Windows

As winter approaches, it’s a good idea to check your home to ensure it’s as thermally efficient as possible, to help keep your heating bills down. A main cause of heat loss and energy inefficiency in the home are draughts, with draughty windows being a common problem. In this article we'll explore easy ways of draught proofing windows. You'll find DIY step-by-step guides to window draught proofing, helping you make your home more comfortable and energy efficient.

Topics:

1. Finding Window Draughts
2. Controlled Ventilation is Not a Draught
3. DIY Ways to Draught Proof a Window
4. Easy Fix Self Adhesive Strips
5. Draught Proof Shrinking Film
6. Silicone Sealant & Calk Filler

Finding Window Draughts

To find the source of a draught might be easy; it may be obvious where it's coming from by the direction cold air is flowing. On the other hand it might not be obvious and you’ll need to go looking for possible causes.

If the draught is coming through your front door, look at this guide to find DIY ways to fix it. If a window is the culprit, read on. 

As you might expect, the first thing to do is look for gaps and cracks in your window, window frame and the surrounding wall. Use your hand to feel around your window for cooler air, especially when it's windy outside — a good tell for a draught is if a curtain or blind at the window moves during windy weather.

You could also use a gas fire lighter to help find draughts. Simply take the lit fire lighter and slowly move it around the frame and window edge. If the flame flickers there's a good chance you will have found the source of a draught.

Controlled Ventilation is Not a Draught

Controlled ventilation does not cause draughts. Remember, not every gap around your window and window frame will be the source of a draught. It's important to understand that your home needs to ventilate moist air to avoid condensation and damp. This is especially so in rooms that naturally are higher in moisture, such as the kitchen and bathroom.

When draught proofing your home you must never block extractor fan outlets, air bricks or wall vents. Look out for window trickle vents too — these are vents in the window frame that let fresh air circulate in a room. As the name suggests, air trickles through the vent and normally won't cause a draught.

DIY Ways to Draught Proof a Window

Let's look at three of the most common ways to stop or significantly reduce draughts from windows:

• Self adhesive draught strips

• Draught insulation film

• Silicone sealant and calk filler

Easy Fix Self Adhesive Strips

Self adhesive strips help create a tight seal at a window’s closing edge. Strips are available with different profiles, thicknesses and in different colours.

Note that if your strip is too thin it won't stop the draught. If it's too thick, your window won't close properly.

You’ll need some basic tools and materials to get the job done:

• Self adhesive strips

• Measuring tape

• Scissors or utility knife

• Clean cloth

• Soapy water or white spirits

• Pencil or marker pen 

Step 1: Clean the window frame

Use a clean cloth with soapy water or white spirits to clean the frame. Remove all dirt, dust, grease and grime, and dry properly to ensure the strip sticks properly.

Step 2: Measure up

Measure the width and height of the window frame where you fit the foam strips. Make sure to measure the top, bottom and sides separately as they may vary slightly.

Step 3: Cut the strips

Based on your measurements from Step 2, use scissors or a utility knife to cut the strips to the right length. Make sure to cut them slightly longer than the measured length to ensure a snug fit.

NOTE: The strip may be shaped like the letter P. If so, ensure that the protruding part of the P profile is facing up and outward. If you have square or E shape strips, there is no specific right way up.

Step 4: Apply the strips

Peel the strip’s backing paper to expose the stick side. Start at the window corner and press the strip, sticky down, firmly against the frame, aligning it with the edge. Take care not to stretch the strip.

Continue pressing the strip along the window, making sure it's centred and straight. Trim any excess at the end.

Step 5: Repeat as required

Ensure that each strip meets at the corners to create a complete seal. Press down firmly to make sure the strip is secure. Note that foam draught strips can be used for sky lights and loft hatches, which can be a major cause of draughts in the home.

Step 6: Test for draughts

Once you've applied the strips, close the window and check for any gaps or draughts. If you find areas where the seal isn't tight, replace the strip that has come loose.

Check out this video to see how easy it is to use slef adhesive foam strips to fix window draughts. 

 

Draught Proof Shrinking Film

Adding an insulating film to single glazing can be an excellent draught excluder to help keep cold air out. It acts as a kind of temporary secondary glazing. It's straightforward to fit and is very effective.

Here's what you'll need:

• Insulating film

• Measuring tape

• Hair dryer

• Scissors or utility knife

• Clean cloth

• Soapy water or white spirits

• Pencil or marker pen

Step 1: Prepare the working area

Clean the area where the film will adhere to the window frame using soapy water or white spirits with a clean cloth to thoroughly remove any dirt and grime. Ensure the area is completely dry before continuing.

Step 2: Measure and cut the draught proofing film

Measure and note the width and height of your window frame.

Unroll the window insulation film on a flat, clean surface. Cut the film to size using your frame measurements, leaving an extra inch or two on each side to ensure it covers the entire window — you can trim it later.

If your film kit doesn't include a cutting tool, use scissors to make a clean, straight cut. You can also use a utility knife or box cutter for precision.

Step 3: Apply double-sided tape

Starting at one corner of the frame, apply the double-sided tape around the entire perimeter, ensuring that the tape is flush against the frame surface.

NOTE: If your window is large, you may need to use multiple strips of tape. Overlap the ends of the tape slightly to ensure a continuous seal.

Step 4: Attach the film to the frame

When in place, carefully peel the protective backing from the double-sided tape. Align one edge of the film with the top edge of the frame. Press it firmly against the tape.

Slowly unroll the film down, smoothing it out as you go to avoid wrinkles. Make sure the film is fairly taut, but not stretched.

Step 5: Seal the film

Once the draught excluder film is stuck into place, use a standard hairdryer on a low or medium heat to gently heat the film along the edges. As you heat the film, it will shrink and conform to the frame, creating a tight draught barrier.

Start on the lowest heat setting and keep the hairdryer moving to prevent overheating and potential damage to the film.

Step 6: Trim Excess Film

After you've heat-sealed the film, use scissors or a knife to trim excess film hanging over the frame edge. Be careful not to cut too close to the tape, as this could compromise the film seal.

Step 7: Final Touches

Inspect the draught excluder film to ensure it's securely in place. If you notice any gaps or areas that need extra attention, use the hairdryer to reheat and reshape the film as needed.

Silicone Sealant & Calk Filler

If you have draughts coming through gaps between the frame and surrounding wall, use silicone sealant or calk filler. Calk is best for filling indoor gaps and cracks between the frame and wall. Silicone is weather resistant, so is best for filling masonry outside.

To draught proof using sealant you’ll need a few simple tools and materials:

• Silicone sealant or calk filler

• Utility knife

• Scraper or putty knife

• Masking tape

• Warm soapy water or white spirits

• A clean damp cloth or sponge

Step 1: Prepare the Area

Clean the frame and surrounding area thoroughly to remove dirt, dust, and grime. Use a soft cloth with soapy water or white spirits to do this. Allow the cleaned area to dry completely before proceeding.

Step 2: Find Draughts

Carefully inspect your window to locate any gaps where the frame meets the wall, as well as gaps between the frame and the glass.

Step 3: Apply Masking Tape

To create neat, straight lines, and to prevent excess sealant from spreading, apply masking tape to both sides of the gap you intend to seal. This will also act as a guide when applying the sealant – this is not so important for outdoor sealing.

 

Step 4: Open the Sealant Tube

Cut the nozzle of the sealant tube at a 45-degree angle, making sure the nozzle opening is large enough to fill the gap, but not so wide that the sealant is unable to properly fill the gap.

Step 5: Applying the Sealant

Hold the sealant tube at a 45-degree angle to the gap and apply gently and steadily, moving the along the gap as you go, from top to bottom.

Apply a continuous bead(s) of sealant, completely filling the gap, ensuring it’s filled along its entire length.  Obviously you will need to apply less sealant for small gaps and more sealant in larger gaps.   

Step 6: Smooth and Shape

After applying the sealant, use a scraper or putty knife to smooth and shape it — or if you don’t mind getting messy, use your finger — to completely seal the gap. Make sure that the sealant is smooth and even along its entire length and the gap is completely sealed.

Step 7: Remove the Masking Tape

Before the sealant dries, carefully remove the masking tape. This will leave you with clean lines.

Step 8: Allow to Dry

Give the sealant time to dry according to the manufacturer's instructions. This typically takes 24 hours or more, depending on the type and brand of sealant you use.

Once the sealant is fully dry, check to ensure that the draughts have been effectively sealed.

Final Thoughts

Draught proofing your windows is a practical and cost-effective way to improve the comfort and energy efficiency of your home. Whether you choose foam strips, window film, sealant or other methods, the key is to ensure a proper seal.

These common draught excluder methods ensure that warm air in the home isn't compromised. They’re an easy fix for DIYers who want to fix draughty windows to increase home energy efficiency and save money this winter.

Discover more about how to fix draughts in How to Draught Proof your Home. 

For more DIY inspiration, visit Hiatt Hardware and browse a broad range of how-to guides, related articles and insights.