This might be worth reading before you add extra insulation to your loft.

jhs14

escapee wrote: »

But why don't the companies who fit this know the procedure, I remember the young lad sent to do ours and recall him saying he hated the job, especially in the summer months. I think companies are latching on to this for quick profit and not considering the customer and any future problems.

I think you've answeed your own question there!

Our windows are double glazed yes, I can't speculate as to why we get condensation now and didn't beforehand. All I know is that the house feels colder (as though cool air is now trapped internally) and if I knew then what I know now, I wouldn't have had it done. I advised my next door neighbour of this when he was approached about three years back, he ignored my advice and now complains of the same issues (house feeling cooler and damp). The neighbours living across from me have moisture dripping down the internal walls in the winter time, they've had professionals out to investigate and feel the problem is something to do with the insulation in the loft but haven't yet determined a remedy.

All houses were perfectly fine prior to the Government initiative to make homes more 'efficient'.

I do sympathise, but these are problems with shoddy installs rather than inherent problems with insulation. There's no way your house can be cooler now than before CWI - have you measured this? Is it actually colder, or does it just feel colder because of the damp? Are fuel bills lower?

'Cool air being trapped' is impossible, unless you maintain an internal temperature cooler than the outside temperature.

You have to be careful with insulation but it's not rocket science. Warm inside air holds water which will condense if it hits a cool surface - you have to stop that happening. You either install a vapour barrier to prevent the air seeping through the insulation, or keep the cold side of the insulation well ventilated (ie eaves space in a loft).

jeallen01

jhs14 wrote: »

I think you've answeed your own question there!
I do sympathise, but these are problems with shoddy installs rather than inherent problems with insulation. There's no way your house can be cooler now than before CWI - have you measured this? Is it actually colder, or does it just feel colder because of the damp? Are fuel bills lower?

'Cool air being trapped' is impossible, unless you maintain an internal temperature cooler than the outside temperature.

You have to be careful with insulation but it's not rocket science. Warm inside air holds water which will condense if it hits a cool surface - you have to stop that happening. You either install a vapour barrier to prevent the air seeping through the insulation, or keep the cold side of the insulation well ventilated (ie eaves space in a loft).

I totally agree with everything you say - my own experience bears it out.

When I installed a (by modern standards!) low level of interior solid wall insulation I made sure that I used material with integral vapour barriers.


As for the roof insulation, I used fibre glass above the bedroom ceilings without vapour barriers - but the roof space was well ventilated (ready "draughty"!). However, when I added solid insulation between the rafters, I made sure it had (foil) vapour barriers.


I have never had condensation problems apart from the occasional minor bathroom/ kitchen window issues as previously mentioned - and I got a GDHIF deal earlier today to add additional external solid wall insulation to two exterior walls (:D) without any worries about more condensation being a problem in the future.