Loft Insulation

[BazzaS]

The loft of my daughter's 'new' house is insulated - 100mm. From what I can tell from the paperwork this insulation was laid in the 1980's. It appears to be fibre rolls, still quite firm but appears to be quite dirty in places (presumably where there once was roof leakage).
I know insulation should be deeper than this.

My question is does loft insulation "go off" over time and if not I intend to lay a layer across the existing - is this sensible ?

Thanks

 

[phatboy]

If it's still about 100mm tall, then it's not compressed and should be fine.

The first could be air blowing through from the eaves, so no worries.

Top it up with 200mm, and job done! Maybe wait for cooler weather though...

 

[stealthwolf]

As above. If you're not using the loft for storage, get the super top up loft insulation which is 200mm rather than standard top up which is 170mm. I'd also echo the advice about doing the work when it's colder. I did it in winter when it was frosty outside and even then it was easy to get hot and sweaty very quickly. Especially if you wear disposable overalls, dust mask and eye protectors as I did.

 

[foxhole]

You might find cheaper to purchase during the summer.

 

[cdbe]

Might be worth a few minutes researching whether you can get it free under one of the ECO schemes - it changes all the time but loft insulation is one that's not generally means tested.