Sagging floor

Magic ]=) · 30-10-2019 1:24pm #1

We're in the process of cleaning up and small upgrades. Wanted to put laminate floor upstairs but.

We have a converted attic. Right above the hallway there's a bathroom and balcony.
https://i.imgur.com/eEbvHsd.jpg

Floor under the bathroom and balcony is sagging a good bit. Sag is coming all the way from under the velux window to the end of balcony. Take a look at the metal level and the gap below:
https://i.imgur.com/lFHEnrx.jpg
https://i.imgur.com/KfHTQyD.jpg

Metal level spans from hallways wall to wall so it's sitting on the highest points where floor should be.

Some of the joists seems to be lower near the balcony edge.
https://i.imgur.com/OziLl44.jpg

Spindles are loose and can be easily removed where the sag is.

Could someone shed some light if it's a big job to fix and what would be involved.

Calahonda52 · 30-10-2019 4:17pm

Why not just post the pictures, serious privacy/cookies/malware issues with that site

D13exile · 30-10-2019 5:24pm

Hard to tell as I can't access the pictures but from your description, is the attic conversion supported on steel? If not, you may have big trouble as the weight of the roof is bearing down on the joists with no proper support. Call an Engineer in immediately as this sounds very worrying.

Magic ]=) · 30-10-2019 6:52pm

Provided links to full size photos for better viewing. Can try to post pic but will be limited in size and won't provide best overview. Will put them up later

DublinDilbert · 30-10-2019 7:06pm

It looks like someone has notched the joists to go over the flange of the steel rsj, so the can attach the down stairs ceiling. It looks like the notches aren't even or the steel has deflected under load, I would guess it's the first not the last option.

A couple of points, the bearing of the joists on the steel looks very small (50mm??) they put infil timber into the rsj (which is often done) but then you normally use joist hangers and secure these to the infil. It's not clear what the timber infil is doing. Looks like they combined two correct methods together and botched it completely, when one method would of done.

Most options risk damaging the ceiling below. You could try shim under the notches of the low joists, using some mild steel as shims. You could also use some joist hangers, provided the infill within the rsj is secure ( use wooden wedges on top of the infill if it's not). Plank of timber and acro prop could be used to lift the joist, for either of the above.

GreeBo · 30-10-2019 7:56pm

^
Are they notched to support a nailing edge for the ceiling below?

I cant see what the timber they are notched around is even doing, just looks like a bit of 2x2?

DublinDilbert · 30-10-2019 9:42pm

GreeBo wrote: »

^
Are they notched to support a nailing edge for the ceiling below?

I cant see what the timber they are notched around is even doing, just looks like a bit of 2x2?

I think they are notched around the bottom of an RSJ, if i'm looking at the picture correctly.

Calahonda52 · 30-10-2019 10:56pm

I don't see no rsj... could be a 9 by 3, as in my house with the x by x nailed on

Magic ]=) · 31-10-2019 1:11am

1.

2.

3.

4.

Magic ]=) · 31-10-2019 1:56am

No. There's no rsj as far as I can tell. What you see on the plasterboard ceiling under the notch is a pressure treated 2x2.
That 2x2 is nailed to 9x2 and there are three of them running parallel under spindles.

Black lines are walls
Green lines are joists
Red line is what the joists are attached to
Bottom of the page is where the entrance to the house is.

So I you can see that red line which is made of three 9x2 running parallel are attached to joists on either end.

As for lifting the joists. Look at photo no 4 and see joists ends - they're only about 6mm below the edge of the board that runs perpendicular to them. Sag by the bathroom door is about an inch deep. So raising joist by 6mm to the edge of the other board will not eliminate the depression in the middle.
I'm starting to think the whole length is crooked and I'm looking at replacing 2-4 joists running above halway.

Calahonda52 · 31-10-2019 9:18am

Thanks for posting pictures.
No need to replace, just run some straight pieces along side the bowed ones, and screw them to existing

GreeBo · 31-10-2019 9:20am

So is the 2x2 just a nailing edge for the plasterboard underneath?

What span are those joists?
Was the attic designed to be converted...?

Calahonda52 · 31-10-2019 11:04am

GreeBo wrote: »

So is the 2x2 just a nailing edge for the plasterboard underneath?

What span are those joists?
Was the attic designed to be converted...?

Whats your thinking re the attic question?
Just wondering?

Magic ]=) · 31-10-2019 12:02pm

I'll lift the floor again and put a level next to the joists to see if they're crooked.

I suppose running a circa 4m joist with weight on it without any cross support wasn't best idea.

Conversion was done long before we got the house so can't say if it was all well thought and planned.

@GreeBo That 2x2 is more of a support for joists rather than plasterboard. Span is about 30cm between joists

GreeBo · 31-10-2019 12:23pm

'Magic wrote:

;111648140']I'll lift the floor again and put a level next to the joists to see if they're crooked.

I suppose running a circa 4m joist with weight on it without any cross support wasn't best idea.

Conversion was done long before we got the house so can't say if it was all well thought and planned.

@GreeBo That 2x2 is more of a support for joists rather than plasterboard. Span is about 30cm between joists

Ok so the 2x2 is instead of a joist hanger (now I get the earlier posters point!)
But to me and based on what you are saying about 3 sistered length, I dont see any RSJ or infill.
Its just joists nailed to a 9x with a 2x "support"...

30cm would be the spacing, the span is how far each joist is running.
http://www.woodspec.ie/docs/Woodspec%20Final%20-%20Section%20A.pdf
Page 58 I think has the start of the span tables.

I'd be getting someone to take a look and I certainly wouldnt be putting anything heavy up there...

Calahonda52 wrote: »

Whats your thinking re the attic question?
Just wondering?

I guess that if it wasnt designed to be converted and someone just "made it livable" and added access then perhaps its just not structurally sound at all.

The joists look to be big enough, but it would depend on the span...perhaps there was a load bearing partition wall underneath than was removed as part of the renovations, for example.

I cant see any reason why the joists would just sag if they are properly specced for the span and they havent just slipped (which it seems they havent)

listermint · 31-10-2019 12:33pm

GreeBo wrote: »

Ok so the 2x2 is instead of a joist hanger (now I get the earlier posters point!)
But to me and based on what you are saying about 3 sistered length, I dont see any RSJ or infill.
Its just joists nailed to a 9x with a 2x "support"...

30cm would be the spacing, the span is how far each joist is running.
http://www.woodspec.ie/docs/Woodspec%20Final%20-%20Section%20A.pdf
Page 58 I think has the start of the span tables.

I'd be getting someone to take a look and I certainly wouldnt be putting anything heavy up there...

I guess that if it wasnt designed to be converted and someone just "made it livable" and added access then perhaps its just not structurally sound at all.

The joists look to be big enough, but it would depend on the span...perhaps there was a load bearing partition wall underneath than was removed as part of the renovations, for example.

I cant see any reason why the joists would just sag if they are properly specced for the span and they havent just slipped (which it seems they havent)

Theres no RSJ, the joists are handing off what looks like doubled up joist at the stairs. hence the sagging.

_Brian · 31-10-2019 12:37pm

Get an engineer in to look.
May be it was a poor job and was installed like that rather than gotten like that.

Maybe it has settled and will go no further.

GreeBo · 03-11-2019 10:39pm

listermint wrote: »

Theres no RSJ, the joists are handing off what looks like doubled up joist at the stairs. hence the sagging.

The joists at the stairs aren't saggingb though... Or are they OP?

Magic ]=) · 10-11-2019 8:49pm

Sorry. Was away for a few days and missed that. No. No sag at the stairs.
I'm waiting for someone to come over next week and have a look at this. Will post update on what contractor said in a few days. Everyone seems to be busy and hard to get someone in even to have a look.

whizbang · 11-11-2019 2:28am

This is pretty standard stuff as far as i can see. Absolutely Nothing to worry about.

In general, 9" joists from suppliers can vary by 1/2" in each batch, and even more when you add in curvature..
Then add in to the mix, a 17y old teenager on his first job: given the task of notching out.
He is always going to measure up 2" from the bottom, rather than down 7" from the top. And probably not even sure which side of the pencil line he is supposed to cut either! So easily another 1/4" added into the variance.

The fitter will almost always fit a joist with its natural sag or curvature downwards, because the joist will be much more stable; Ie. It will stay where it is while he goes off to look for more nails and noggins..or even while he holds up the end to measure the length. Yes it would be technically better to fit it the other way around but...!!

In th image OziLl44, you can see the difference in the joists from No.2 - No.3 numbered from right to left.

Sagging floor

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