condensation between rafters

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I have recently increased the depth of my loft insulation and tacked insulation across my roof rafters, ( the thin silver stuff ). I now have moisture behind the roof insulation , not so much during this present cold snap, but a month ago. I have maintained the gap between insulation and eaves.
I have also maintained a flow from one soffit to the other, ( front to back ).
Tile vents have been suggested but because I have insulated right across the rafters doesnt this make a series of seperate voids or cells with one cell cut off from the next one?
One further question - what is the reason fro fitting a netting "hammock" under floor insulation?
I would be grateful for any help on any or all of these matters.
 
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Re: Netting hammock

Because if you are using wool-type insulation, how else will you hold it up ? Good wishes and pure thoughts maybe ?
 
I've got this thing called a ceiling which is somehow managing to stop it falling through into the room below.
 
Exactly. you've got a ceiling, but if you look at what you first posted you asked why is netting used...

"....... under floor-insulation.. "
 
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The floor is in the loft and the ceiling is in the rooms below. Get the picture?
 
He does understand what you mean, he was just answering your question regarding the netting. You use it to hold the insulation up between the rafters, which is being used more often now as an extra layer of insulation which doesn't reduce the storage space as much as doubling up the layers rolled out above your ceiling.
 
Can somebody read my original post properly and provide advice to my query on netting for FLOOR insulation in a loft?
 
I have maintained the gap between insulation and eaves.
I have also maintained a flow from one soffit to the other, ( front to back ).
Do you have an air flow from the bottom soffit and vented out at the top via ridge tile vent? If you're getting condensation there's a possibility there is no air movement therefore needs more ventilation
 
Each gap between the rafters is isolated from the others because I have fixed the foil type insulation across them, so any tile vents would only ventilate the gap between the rafters where it was fitted, if you see what I mean.
 
if you are getting condensation, then you do not have enough air flow. check your insulation is not to close to the roof timbers, pull it back a few inches and see if this makes a difference. the netting you refer to, i have seen this only a couple of times and only on housing association houses that were timber framed. they put the insulation in the walls and ceiling before any other trades got in the house so there would be no ceiling to hold it up, a very strange way to insulate a loft if you ask me but not a surprise when a housing association is involved, they do have some strange ideas. :eek:
 
Wire netting (chicken wire) can be used on the loft floor with fire resistant insulation on top to prevent the spread of fire.
 
Each gap between the rafters is isolated from the others because I have fixed the foil type insulation across them, so any tile vents would only ventilate the gap between the rafters where it was fitted, if you see what I mean.
You need ridge tile vents and not tile vents plus a 100mm insulation gap at the top and bottom to allow the air flow.
 

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