How could tell if the plasterboard is for exterior alfresco ceiling?

[emmab1986]

We have a alfresco area, the plasterboard ceiling was observed with some water stain following a storm event. there is no issue for any other thing, and the insurer said the water stain may be caused by the wrong plasterboard, the interior plasterboard was installed exterior. how to tell if the plasterboard is interior or exterior when the plasterboard has been attached to the ceiling, with no label, no stamp and couldn't see if there is blue paper?

I went to bunnings another day, and a guy in the plasterboard section told me the plasterboard is all the same for internal and external uses. Is this statement correct?

Help, please!

[Jewelleryrescue]

Hi @emmab1986 

The real issue here is that the roof/ structure leaked during the storm event.  So a storm with high winds can blow water backwards at times and can momentarily defeat normal weather tight areas and standard building techniques> ,  Its almost impossible to waterproof 100% That is why we have insurance usually

Is the structures roof and water proofing, ok? not damaged Needs to be fixed if it is  thats a given.  This is for insurance usually.   let's assume it not damaged for 1 min. 

 During a freak storm event and structure water incursion. Plaster board is not designed to be wet and will readily water stain in future major storm events may get soggy and collapse if it is wet enough. So in deeper hindsight a wet area interior liner may have best suited that area.

So for the future it may be better to use Duratex blue board, or Villa board or durasheet cement cladding if your gyprock  collapses  to be able to withstand freak weather events (I make these comments with the design of your structure and the cause of your leak being unknown.  ) These wet area materials still may be leaked on and even stained but they are designed for wet areas and will usually survive intermittent wetting if that is a regular occurrence. 

[emmab1986]

The structure roof is okay, tiles lined well. The insurance plumber found the sarking underneath the tiles was deliberately damaged during the construction to allow trades enter the void doing some work. But the rafter less than 6m and the roof pitch is 22.5 degree, from building code point view, the damage sarking is not non-compliance as no requirements for the sarking in this case (the builder argued). there is no water marks or mould on the sarking damage areas where rafter and frame exposed.

The insurer denied the claim citing the interior plasterboard was installed exteriors.

that's why I asked how to tell the plasterboard is exterior ones?

[MitchellMc]

Hi @emmab1986,

I've been advised by our plasterboard supplier that water staining can occur on internal and external plasterboard if water accumulates on it and leaks through. Staining alone, would not indicate that it is definitively an interior plasterboard. Exterior plasterboard is water resistant and not waterproof.

For CSR, their sheets are typically branded on the side edge, which would obviously be difficult to access. 

Regarding interior and exterior plasterboard being all the same, that is incorrect. Exterior Aquachek is used outside and in wet areas and interior plasterboard is used for internal rooms.

Please let me know if you have further questions.

Mitchell

[emmab1986]

Greatly appreciated!

I have more questions though:

1. I have read some articles about Table 4.2.2 AS/NZS 2589 2007 citing there is no requirements to use back-block on the plasterboard ceiling installation back in 2008. Is that correct?

2. If the interior plasterboard was installed externally, what scenarios would be? 

[MitchellMc]

Hi @emmab1986,

1. For the interpretation of construction codes, you'd really need to speak with someone specialising in that area. I suggest, depending on the scale of the damage and situation, that you enlist the services of a qualified building inspector to provide their own report.

2. I'm not entirely sure of your questions here. Could you please provide more details? Interior plasterboard should not be used outside, whether it is a covered area or not.

Mitchell

[emmab1986]

Thanks, MItchell.

Sorry for the unclear message. 

It's alfresco ceiling, semi attached to the building (two side attached the house) with tiles roof. I mean if the interior plasterboard been installed exteriors, what kind of damage the ceiling would have? We only have water marks along the edge, want to know if these are not the signs of the wrong plasterboard installed.

[MitchellMc]

Hi @emmab1986,

According to our plasterboard supplier, if the correct exterior plasterboard was used and there was a leak that saturated the board, water stains could be expected too. So, in their opinion, speaking to their own products, a stain on the plasterboard is not solely an indication that the wrong interior board was used.

Mitchell