Windows – leaks

Causes

Putty has failed (cracked, fallen out)  - timber windows

Glazing rebate not sealed when glass installed 

Glazing beads (rubbers) have shrunk, fallen out – aluminium doors and windows

Insufficient flange cover at jambs - aluminium doors and windows

Listed under: Interior, adhesives and sealants, glass, metal, aluminium, timber and wood-based, putty, timber, windows, moisture, leaks

Cause

Putty has failed (cracked, fallen out)  - timber windows

Repair

  • carefully scrape out the remaining putty with a hacking knife or a chisel

  • remove the glazing tacks with a pair of thin-nosed pliers, then remove the glass

  • remove any remaining putty from the rebate; clean and then prime the rebate with a good quality primer

  • after the primer is dry, insert new putty in the rebate, then gently press the glass into the putty – 2 mm of putty should be between the back of the glass and the timber window frame

  • install new glazing tacks and press putty around the edge of the glass

  • smooth the putty to a consistent slope (around 30–45 degrees) around the window edge with a putty knife

  • paint putty after 2 weeks, ensuring that all the exterior putty and 2 mm of the glass is painted

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Cause

Glazing rebate not sealed when glass installed 

Repair

  • remove putty, glass, clean and then seal rebates with two coats of primer, reglaze window (as above for putty)

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Cause

Glazing beads (rubbers) have shrunk, fallen out – aluminium doors and windows

Repair

  • replacement seals are available from hardware suppliers or window frame manufacturers. Take a sample of the existing seal to ensure a correct profile and size match

  • remove old seals by starting at one corner and prising out a section of the seal. Once a section has lifted, the rest of the seal will generally easily pull out

  • cut a replacement seal longer (5–8 mm approximately) than the size you want. When inserting new seals, length should be slightly oversized to give a tight fit

  • starting from the top centre of the frame, push the seal into the gap between the gasket groove or bead and the glass. Spraying soapy water on the seal can help installation

  • work the seal into the gap all the way around the perimeter of the frame. Take care to ensure that that the seal is properly fitted into the corners of the frame

  • do not stretch the seal as it is being inserted. If a seal is stretched during installation it will eventually retract, leaving a gap where the two ends of the seal meet

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Cause

Insufficient flange cover at jambs - aluminium doors and windows

Repair

  • install 30 mm wide scribers butted and sealed to the flange or facings rebated over the flange to aluminium window jambs

  • consider replacing existing aluminium windows with frames that have larger jamb flanges

  • where it is suspected that the building may be leaking and there is a risk of damage, engage a registered building surveyor to report on the building and advise on repair options.

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