DraughtBusters

Energy saving advice and help

  • About
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    • A typical DraughtBust
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  • Draught proofing
    • How to get started
    • A Case Study
    • Why draughts?
    • Windows and doors
      • Front Door
      • Draughty roof windows
      • Trickle Ventilators
      • uPVC door problems
      • UPVC window seals
    • Redundant AirBricks
    • Floors
    • Loft and first floor ceilings
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    • Pet Flaps
    • What is going on under your bath?
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    • How to survey a building for draughts
    • Problem encountered during 2021/2022
    • Dry lined homes
    • Modern timber frame
    • Victorian terraced houses
    • Chalet Bungalow
    • Cross walled homes
    • Early cavity wall homes
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  • Help Reducing Energy Use
  • Advanced Air Sealing
    • Problems with Drylined Homes
      • Problems with dot and dabbed walls
      • Around openings in walls
      • Draughts in the first floor void
    • Going Further
      • First Floor Void
      • Condensation mini case study
      • Controlling your heating system
      • Heat loss from unused chimneys
      • Types of damp in the home
      • Draughts and condensation
      • In House Winter Cooling Systems
    • More Advanced
      • Upgrading to Underfloor Heating
      • Lead Pumping
      • Why so many flat roofs fail
      • Summer Condensation
  • Contact

uPVC window seals

We are finding an increasing number of problems with uPVC window seals. The predominant seals are rubber and these go brittle and loose their springiness allowing draughts to enter the building (see if your curtains move when it is windy outside).

In other cases, seals and glazing rubber seals have shrunk back, leaving gaps at the corners. This could be as a result of the original seals having been stretched into place rather than pressed into place.  Alternatively the seals may be shrinking with age, UV exposure or ozone action. 

Some budget windows omit the outer seal on the sash but generally have the grooves for them present. Replacement seals are readily available and if yours have failed for any of the above reasons they should be replaced. Please do this rather than replacing whole windows. 

My own windows are wood clad with insulated aluminium sections on the outside with two rubber seals and two foam filled nylon tube seals to each sash. If I had uPVC windows with rubber seals I would seriously consider using encapsulated foam seals.

This happened with the uPVC windows we inherited. Massage the seals back into the corners and add a blob of superglue in the corner sticking the seals together. If they have shrunk a lot do alternate corners in pairs with a day in between. Voila!

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