Gaps Around Window Frames
Gaps can appear around any type of window frame, on a house of any age. They may be caused by natural settling of the house cracking existing mortar or just by bad workmanship when the window was fitted. In either case, gaps around a window frame are not good and can lead to damp penetrating the internal walls window and beyond. Once damp penetrates, the gaps will usually get worse which, in turn, allows more damp to penetrate.
Using Mortar
Gaps over about 10mm should ideally be filled with mortar. You can buy ready-mixed mortar in fairly small bags, which are ideal for jobs like this. Mix up the mortar following the manufacturers instructions and then use a stiff brush to clean up any dust and loose material around the gap. Brush or spray the gap with water until the inside is damp.
Using a small trowel, press the mortar into the gap until it is filled. Use the face of the trowel to smooth the mortar flat and level with the surrounding brickwork. You now need to allow the mortar to dry completely. It is a good idea to further seal the window frame with frame sealant.
Frame Sealant
Small gaps around a window frame (less than 10mm) can be filled using frame sealant. Frame sealant is available in several different colours including white, grey, brown and transparent, and usually comes in a tube which needs to be fitted into a cartridge gun. You can also buy it in tubes that are applied by turning a screw cap on the bottom if you do not have a cartridge gun.
Cut the nozzle on the tube of frame sealant at an angle and, depending on how wide the gap is, either close to the tip or slightly further back to produce a large bead. Brush all around the frame using a stiff brush and then start to apply the sealant. Aim the nozzle into the gap and try to keep your movements smooth as you work along it. When using frame sealant, you should apply to all the way around the frame, rather than just where the gap is. If you apply it in a short strip it is more likely to peel away after a short time.
Hopefully Your bead of sealant is smooth and even, but if not, wet your finger and run it along the bead to smooth and flatten it. Let the sealant dry for the recommended time (up to 3 weeks) and you can then paint over it if required. If you are filling cracks with mortar as described above, it is a good idea to further seal the frame with sealant once the mortar is dry.
Large Gaps
If you have very large gaps around a window, you can fill them using expanding foam. Inject the foam right into the gap until it fills up and expands well outside of the hole. The foam will expand into all of the cracks and crevices inside the hole and provide a really good seal. When the foam has fully set, you can trim it off, sand it down and even plaster and paint over it.
Related DIY Guides:
- Painting Wooden Window FramesAlthough this might seem like a simple job, painting window frames should always be completed in a certain way. ...
- Maintaining Metal WindowsNot many houses still have old steel-framed windows nowadays, but some do and unless you plan to replace them with wooden or UPVC frames, you...
- Choosing FillerThere are many different types of filler available, and each has different use around the home. Choosing the right filler for the job will help...
- Repointing BrickworkThe natural action of wind and rain will cause mortar between the bricks of your house to loosen, crumble and wear down. This not only...
