Smelling loft insulation

[BRENDANOFTHELOFT]

Hi, I have a fifteen year old house and the existing loft insulation, brown fibre wool, is really starting to smell. The centre section is boarded out but there are gaps around the boards. At the eves, daylight can be seen so ventilation is possible. When it is cold, condensation drips off the roof felt. I was going to replace all the insulation but your forum has advised other users to to lay the new stuff over the old. What do you think? Renew the insulation and re-board or do I have a more serious problem?
Thanks.

 

[JohnD]

You have to fix the condensation problem. More moisture is getting in than is getting out.

See if there is a through flow of air

Look for uncovered water tanks; or tanks that have hot steamy water in them due to a plumbing fault.

Look for leaking pipes or roof.

Verify that excesive humidity from the house is not getting into the loft
- does the bathroom have an effective extractor that is used during and after every bath or shower?
- is an unvented tumbledrier used?
- is wet washing left about the house or draped over radiators?
- does the loft hatch fit tightly? Are there gaps in the ceilings?

 

[BRENDANOFTHELOFT]

Thanks JD. I don't have much condensation. Only the odd drip off the edge of the roof felt. Do you think this could be enough to cause the smell? During summer, when everything is completely dry, the loft still smells!

 

[masona]

Is the smell all over the loft area?

Chemical in F&E tank(?)

Wood treatment(?)

Dead rat(?)

What sort of smell is it?

 

[BRENDANOFTHELOFT]

It is a fusty, damp sort of smell and appears to be worst around the hatch. The hatch is in the middle of the roof area and is near the large cold water tank. It has been smelling for a few years but just recently it's getting stronger. Thanks for your help.

 

[masona]

I'm guessing it's not enough ventilation

 

[JohnD]

Possibly the damp is collecting under the boarded area.

 

[BRENDANOFTHELOFT]

Thanks Masona and JohnD,

I'll remove some of the lagging around the outside edges of the loft and check under the boards for damp. I have also noticed that the builders have left the insulation in place under the cold tank, so this will have to go. I'll let you know the outcome in a few days and thanks again for your help.