Incorrectly Installed Insulation? Information, help, tips and advice on cavity walls, ceilings and lofts etc....

[Red_48]

My homes loft had loose fill fiberglass insulation added over top of fiberglass rolled between joists as part of a government scheme.

However, there is a non perforated radiant barrier under the loose fill fibreglass that I suspect will cause moist air escaping the house to condensate and rot the original fibreglass installed between joists.

I am considering adding more insulation, but want to confirm this is a problem I'll need to tackle first.

[stoneyboy]

Hi red_48,
With all loft insulation there will be a point in the depth of the insulation where damp vapour from the house may reach dew point and condensation will form, this depending on the temperatures on the hot and cold sides.
In your case if the metalised sheeting is lower in the insulation than the dew point then there should not be a problem and adding further insulation on top can only reduce the likelihood of this happening.
Suggest you look at the underside of the metalised layer and if there is no evidence of condensation just add the extra on top.
Regards S

[Red_48]

Much appreciated StoneyBoy.
No evidence of condensation on the underside or dampness but I would need to wait for cooler weather to be sure.

[Red_48]

Mold found on top of insulation that's in contact with the vapour barrier.

Do I treat the insulation with anti mould spray or replace it?

[stoneyboy]

Hi red_88,
Presumably the mould is at the top of the insulation which is under the vapour barrier. If this is correct, has this occurred since you increased the depth of insulation on top of the VB? If not and it is a pre-existing localised condition you need to establish why this is happening - is there a bathroom below the area; is there a ceiling vent below; is there vent ducting in the area; is the insulation above the damp area, above the VB, thin or non existent?
If the mouldy area is wet it's best to remove it and replace it with new.
Regards S

[Red_48]

Correct, the mold is on the top surface of the insulation (which is dry), directly in contact with the radiant barrier.

I have not yet started to add insulation so this mold was present before.

I discovered it whilst installing a bathroom extractor fan and will assess the extent of the mold growth tomorrow. The pictures are of the insulation directly over the shower.

However, the whole house suffers badly in the winter with condensation (>70% RH first thing in the morning), and I'm considering this might be because the warm wet air can't escape through the radiant barrier (RB) installed.

I'm considering removing the RB but, with loose fill glass fiber blown over the top it's going to be messy and I don't know whether to spray anti-mold on the affected areas or pull it all out.

[stoneyboy]

Hi red_48,
Thanks for the response and the pictures. I agree with you that removing the vapour barrier is Important. Cut it in sections and tip the loose fill off. The mould will just die once it no longer has a damp environment so longer term I don't think it will be detrimental.
Regards S

[Red_48]

Thank You!