Loft insulation/ventilation

[a9blue]

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.

[Rich]

Hi A9...

Long time no answer, thought I would chip in on this, as that silver foil stuff is intended to be stapled to the rafters, very loosely, your not looking for air-tight, and should always start at the top and work down, ensuring the lower peices always overlap the higher peices, in case of moisture running down the inside of it.

It is however the case that put simply, non-breathable materials will cause moisture build ups and the only thing you can do is live with it or change it.

That silver foil stuff is far more useful behind radiators

[Gary]

Condensation is almost always because of a lack of ventilation. Are there sufficient soffit vents, more of these will help and be the easiest and cheapest option.

The hammock you're talking about I assume you mean when chicken wire is laid over the ceiling joists in between the ceiling material and insulation above. I think this is a building regulation issue, usually required over old lathe and plaster ceilings to prevent in the event of a fire the flammable insulation falling down with the ceiling onto people upstairs, or firemen fighting the fire.

If your kids are going to be up there playing/banging around and you have lathe and plaster that collapses easily it's worth considering.