Lack of baffling on insulation causing mould ?

[phillip30]

HI all,

would appriciate your thoughts. I have had an ongoing moulding issue for a while, it appears the insulation above the room may not have been baffled correctly. Is it possible this would cause a moulding issue around the end plate of the room ?

Thanks

phillip

[Wayne]

What do you mean by 'baffled'?

[Nick G]

http://homeguides.sfgate.com/important-using-baffles-attic-insulation-78043.html

[sidinz]

I read the linked page, and quite frankly, I'm baffled.

[phillip30]

thanks for the replies and sorry for my delayed response, just realised these replies were here.

my understanding of baffled is where there are joists and the the insulation is taken to the end plate it needs to be taken over and fastened down so air can't get underneath. It appears this wasn't done.

[Wayne]

thanks for the replies and sorry for my delayed response, just realised these replies were here.

my understanding of baffled is where there are joists and the the insulation is taken to the end plate it needs to be taken over and fastened down so air can't get underneath. It appears this wasn't done.

I have never seen that done in NZ.
Impossible to do for a retrofit - can't get to the top plate to staple.
Are you saying that you have mould around the edges of the room?

[phillip30]

thanks Wayne, essentailly developed mould around the endplate of a room. it appears to form in a specfic pattern, someone mentioned that it appeared the insulation has not been 'baffled' which to my understadning means that because it has been layed over the top of the joists it needs to be run over and connected down to prevent air getting underneather.

any thoughts appreciated.

[Wayne]

As I say that never happens that I have seen - the stapling etc to the top plate.
Could the top plate be getting wet?
You would think air movement would be more likely to dry the timbers rater than wet them.
Does the house have eaves? Could this be a sign of a 'leaky building'?

[phillip30]

thanks Wayne, my understanding is that this process is done to prevent air getting under the insualtion as that potentially drops the temprature of that area. the house does have eaves, a few people have had a look at it and it does not appear to relate to a leak

[Keithw]

How many people living in the room ?
What is the air flow like through the room ? - are the windows all closed up for the winter
How far from the bathroom or kitchen is it ?
Is there an unflued gas heater being used ?
What type of heating is being used ?
has a dehumidifier been tried ?
is it wet under the house, causing rising moisture in the room.

Patterns visible in the mould buildup on the ceiling are probably really just a symptom that mould is present at differing amounts due to differing temperatures of the materials. ie the rafters don't get as cold as the surrounding gib / plaster board, so there is less condensation at that point.

I think that trying to pin the problem on whether the edges of the insulation are pinned down or not is really just looking for a scape goat when other (perhaps more obvious) things are really the cause. Bad ventilation, too many people, blocked gutters, water under the house or leaky building etc

[phillip30]

thanks Keith, have look at the other areas but will review. Basically trying to see if there is a specfic cause.

[MikeO]

Is it possible that the insulation in the ceilling has been pushed too far out so that it is blocking air circulation from the eave? When I have installed ceiling insulation I have understood the correct method pushes the insulation as far as the top plate of the wall which leaves a space to allow ventilation into the ceiling cavity above the insulation. So the insulation in the wall is packed against the top plate and the ceiling insulation is sort of at a right angle to that provided an insulated cube which air can ventilate above.

If that was causing the problem it would be a pretty straightforward (although admittedly hot, dusty and all around miserable) job to get up there and pull each batt back and trim a bit off each one. Take a leaf rake or broom or something similar to push each batt down against the top plate as you go. You might also want to pull a few batts completely out to make sure they haven't soaked up water blown in from outside or something.

[phillip30]

Thanks Mike, I will check this

[ivanp]

Installers couldn't push insulation far enough (this is usual), so areas of the ceiling that don't have insulation directly above them (close to external walls) are colder than others, and obviously moisture inside the house will condense on these colder areas of the ceiling, resulting in mould.

Ventilation will probably help. Just make sure installers don't do a cheap job: most of them prefer to put ceiling grills in bedrooms close to doors, just to save few bucks on ventilation ducting. Installing ceiling grills in the far most corners, opposite to doors, is much better, and ducting is not expensive (typical 150mm insulated ducting costs about $27+GST per 6 meter, so probably extra hundred dollars for the whole house)