Loft insulation, polystyrene?

[CVHO]

Hello,

I have been clearing out a section of my loft and discovered that it has been 'bordered' out with timber onto the joists when originally built, 1890ish.

I don't want to remove the wood ideally as they look original and while cleaning I have found bits of old polystyrene packaging have been shoved under as insulation, I am looking to top up the insulation at the moment the build up is this.

1. 50mm fibre insulation
2. Timber boarding
3. 80mm of loosely Broken bits of polystyrene
4. Lath plaster ceiling

Modern wiring is located amongst the polystyrene, is this a fire hazard? It was probably put in mid 70s.

Am I best off leaving the polystyrene or topping it up with more polystyrene and then putting 100mm of insulation on top of the timber my best approach? If I leave as is and just put 100mm more of insulation down would this be OK? It would essentially have a 80mm air gap between the lath plaster and timber

 

[mattylad]

That polystyrene is doing nothing as far as insulation goes, its just rubbish - I'd remove it along with any bricks, lumps of plaster or other debris that's adding weight to the ceiling but then thats a lot of cleaning up.

 

[CVHO]

That polystyrene is doing nothing as far as insulation goes, its just rubbish - I'd remove it along with any bricks, lumps of plaster or other debris that's adding weight to the ceiling but then thats a lot of cleaning up.

That was my fear, I will remove - in terms of putting insulation back is there anything I can put in which is more flexible than fibre insulation? I have seen polystyrene peanuts etc or small balls, is this a viable option?

 

[mattylad]

There probably is but I'm not the person to advise on that as I have only ever had the normal stuff.

 

[Diver Fred]

Duplicate post - deleted.

 

[Diver Fred]

No Way do you want to use Polystyrene - it's flamable and the fumes are dangerous to health (Carcinogenic).

The stuff you are thinking of is Vermiculite but even then that is not the most effective insulation material. It will find gaps and holes to move through and if wind gets into your loft it will blow around similar to snowdrifts.

The best insulation is the rolls of insulation laid out to a depth of 300mm or more.

 

[CVHO]

No Way do you want to use Polystyrene - it's flamable and the fumes are dangerous to health (Carcinogenic).

The stuff you are thinking of is Vermiculite but even then that is not the most effective insulation material. It will find gaps and holes to move through and if wind gets into your loft it will blow around similar to snowdrifts.

The best insulation is the rolls of insulation laid out to a depth of 300mm or more.

The 300mm rolls would be my go to, I am keen not to disturb the timbers that have been put down though, My thinking is that I use granulated cork to fill up between the joists and below the timber (Roughly 80mm) then put 200mm rolls on top of this it will give a good level of insulation and also stop the granulated cork from blowing around, not that it is particularly drafty