20 yr old house, just bought in may; put new roof on/soffit vents installed; have ridge vent & insulation in attic. Ice daming and icecicles still forming over back of house. Icecicles seem to form mostly at roof edges-Any possible answers/solutions??
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DWEinst, I have written a document for my customers to give them some background to the roofing and ventilation issues we have to deal with. If you are interested, let me know and I'll e-mail you a copy (it's in PDF format).
However, to briefly review:
1) is there enough ventilation? (1:300 is the minimum, 1:150 is desired)
2) is the ventilation balanced? (is intake equal to exhaust?)
3) is there any obstruction between the ventilated soffit and the attic space (blocking insulation, incompletely cut soffit wood, blocking header board, etc.)
4) are the outlet vents high enough on the roof to allow proper circulation by convection?
5) are the vents positioned so that they short-circuit each other?
6) is there enough insulation for your climate?
The fact that icicles are forming means heat is being lost from the house into the attic, and there is not enough ventilation to carry away this heat before it melts the snow on the roof.
However, to briefly review:
1) is there enough ventilation? (1:300 is the minimum, 1:150 is desired)
2) is the ventilation balanced? (is intake equal to exhaust?)
3) is there any obstruction between the ventilated soffit and the attic space (blocking insulation, incompletely cut soffit wood, blocking header board, etc.)
4) are the outlet vents high enough on the roof to allow proper circulation by convection?
5) are the vents positioned so that they short-circuit each other?
6) is there enough insulation for your climate?
The fact that icicles are forming means heat is being lost from the house into the attic, and there is not enough ventilation to carry away this heat before it melts the snow on the roof.
