Home Forums General Discussion Conference Call on Internal Moisture and Ventilation – 2 Dec Reply To: Conference Call on Internal Moisture and Ventilation – 2 Dec

Jo Wills

This was a recent post on the CEN forum in response to the question below, I thought it was relevant in light of the first Hub conference call coming up 2nd Dec:

‘There is a lot of condensation in my house – the window sills are covered in water every morning. How can I get rid of it?’

Richard, November 20th, 2013 on 2:30 pm
We have waged a similar battle against internal moisture and window condensation since buying a 1960s Rotorua bungalow in 2007. Previously had geothermally heated wall radiators and in common with other houses of its generation, had no underfloor or wall insulation, nor a ground vapour barrier. In winter condensation puddles on the window sills would overflow onto the floor, and I recently discovered rot in the sills and frames of a number of windows. We installed underfloor insulation, wall-insulated 2 bedrooms, upped the ceiling insulation, installed a heat pump for better space heating, and draught-stopped the doors and windows. All this made the house warmer, but the condensation remained in spite of us diligently opening windows, isolating bathroom moisture, and drying windows each morning with a scraper – through a series of drier/wetter/colder/milder winters.

Finally last summer I got around to installing a PVC sheet moisture barrier under the house. This winter the window condensation was considerably reduced – less effort to dry in the mornings, and the sill puddles were greatly reduced in size. In retrospect I would have tackled the ground moisture barrier first: it would also have made installing the underfloor insulation a more pleasant task!