Gyprock Gurus

[Tandum (Robin)]

I noticed a ceiling problem upstairs the other week and was wondering if what I've worked out makes sense. Two storey Brick and Tile house and the center upstairs looks like this.

http://starshed.net/Roof/1.jpg

See the cornice is pushed down both left and right. That is a join in the gyprock boards along a truss. Put a builders level at either side and it rocks. Put it in the middle and it's flat. The cornice in each room either side is also sagging to some degree and the level rocks there too.

I can't get on the roof to look, it's too high, but I put a canon on a stick with a long USB lead, stuck it out a window and took this shot.

http://starshed.net/Roof/roof.jpg

Obviously there is a busted tile sitting in the channel and I'm sure that will make a decent QLD downpour overflow the channel. That tile is very close to the truss in question.

Will water swell gyprock and cause the issue we are seeing here? There are no water stains at all.

I have a roofer coming in a couple of weeks to do a report and insurance is event driven so I'm hoping a busted tile causing a water leak is the event.

Sound like a plan

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[simmo]

Hi Robin,

How long has it been like this?

Are you talking about half way along the left and right side walls in the photo?

Usually water on gyprock will leave a stain as in colour difference after a while. Also depends on how much is getting through. Any stains?

Looks in the photo that you have a bit of sagging between the ceiling joists. ie. ripples.

Also it looks as though something like a beam above is actually pressing down on the gyprock. Causing the sagging.

Do you have a ladder and a manhole to gain access to the roof space? Other idea could be to use your stick and canon and get a photo of whats above that area.

Can you also please send a close up of the sagging area?

[Tandum (Robin)]

Hi Simmo,
The boss changed to much lighter curtains before xmas and that's when I noticed it, but it may have been like this for years, just too dark to see it. We are about to click over to 20 years since hand over.

Yes, half way along. It's too dark for the canon to focus right now but this is an earlier shot of the left side. Not a good one either.

http://starshed.net/Roof/3.jpg

Almost all the ceilings in the house have pillowing to some degree. Shine a torch across them in the dark and they all look pretty similar, even downstairs. There are no stains at all anywhere.

I did a bit of reading and believe they make trusses with a bow in the bottom chord which bends down with the weight of the roof. They are supposed to only apply load to the frame on the outer ends. The rest is supposed to float but can move up/down seasonally.

I've been in the roof space expecting the guprock glue had given way but it hasn't and saw no evidence of water incursion but I did see bird feathers up there?

That roof pic of the broken tile is pretty much right above the problem. We have nothing on the roof apart from a TV antenna.

[troypiggo (Troy)]

Looks to me like there's either a beam or girder truss spanning from wall to wall, and the point load at the walls is too much for whatever is supporting it to handle. Possibly a local failure (sagging) of the top plate in the wall under the beam/girder truss? Just a guess based on photos. You'd need to get into ceiling space to have a look at those 2 spots. You should have a manhole access somewhere to get into roof space. Do it early in morning with this heat

Doesn't look related to the tile in valley gutter or water related.

[AussieTrooper (Ben)]

Originally Posted by troypiggo

Looks to me like there's either a beam or girder truss spanning from wall to wall, and the point load at the walls is too much for whatever is supporting it to handle. Possibly a local failure (sagging) of the top plate in the wall under the beam/girder truss? Just a guess based on photos. You'd need to get into ceiling space to have a look at those 2 spots. You should have a manhole access somewhere to get into roof space. Do it early in morning with this heat

Doesn't look related to the tile in valley gutter or water related.

Agreed. Which actually makes it a more serious issue than a water leak. Get onto this quickly.

[simmo]

I'd say its been a slow process which is why there are no stress related cracks formed from a sudden loading. A bit of seasonal moisture as the beam/truss has deformed would see the gyprock change shape slowly without cracking. Shouldn't be too dangerous in the meantime but i wouldnt sleep or sit under it in.

You've got a carpenter coming and if he's a good roofie then you should have no worries.

Might be a case of jacking up the roof over the area and strengthening it up.

[Tandum (Robin)]

Cheers. There's no point in me crawling back up there again, I have no idea what I'm looking for. The roof guys will be here next week.

And so long as i can get insurance to pay for it, I'll be happy.

[Tandum (Robin)]

Thanks for the input guys.
Your right, no water leaks, that truss is riding lower than it should be.
It'll cost less to do the carpentry than the insurance excess would be.
We'll fix the gyprock through out the whole house before we sell it.
I'm happy