Issues with I-joist fitting

[Omnibuswoman]

Following some enquiries with the joist manufacturer, a number of issues have been identified with the fitting of the I-joists and build that are going to require remediation. These include a failure to place blocking plates between joists as they sail across the supporting walls, meaning that the joists are beginning to twist (see photos below). 
 

The joists are glued to the eggerboard above, so making the joists straight again to fit the blocking plates is going to be extremely tricky. If they are not straightened, they won’t perform the function they are designed for. 
 

In addition, the supporting walls that sit above each other are not, in fact, sat above each other. There is approx 50mm between the face of the wall on the first floor and the face of the wall on the second floor (we discovered this when trying to send a pipe up from one to the next, and realised that it emerges in a different place than expected). 
 

The technical manager at the I-joist company is “very concerned” about this, as the joists are not designed to carry the second floor load - it should be transferred down via the walls sitting atop each other. 
 

We now need to explain these issues to our builder and ask him to undertake the difficult job of remediating these issues. Has anyone experienced anything similar? And does anyone have any advice about how to go about this? Should we consider getting an independent structural survey done, or involve Building Control to strengthen our position? 
cheers 

Omnibuswoman

 

[Omnibuswoman]

 

This joist has been rested on a scrap bit of OSB because the wall was built too short…

 

 

 

Not all hangers have been nailed to the joists. 

 

 

[joe90]

43 minutes ago, Omnibuswoman said:

Not all hangers have been nailed to the joists. 

48 minutes ago, Omnibuswoman said:

Should we consider getting an independent structural survey done

Not in my opinion, tell the builder it’s not right and to correct it. Why should you spend more money.

 

48 minutes ago, Omnibuswoman said:

The technical manager at the I-joist company is “very concerned” about this, as the joists are not designed to carry the second floor load - it should be transferred down via the walls sitting atop each other. 

Tell the builder this.

[Omnibuswoman]

Thanks Joe. We are anticipating a degree of resistance from the builder, and he has already popped round to have a look at some of the concerns (he’s not aware of all of them yet). He mostly wandered around explaining how these things “should be alright” (I.e. he doesn’t need to remediate them), while HWMBO wandered after him pointing out that we would let the I-joist engineer be the judge of that!

 

The builder seems to be a decent chap, but this is shoddy stuff - not following the plans correctly and not appreciating the significance of getting the structural elements right in order for them to work properly.
 

Best case scenario is a bit of a creaky floor, but worst case is joist failure. I’m

sure most builders would tell themselves that it couldn’t happen, and most likely it wouldn’t, but the risk isn’t zero, and I’m not willing to accept living with the uncertainty just because it’s a ball ache to put things right. 

 

I’ll draft a polite but firm email and see what comes back…

[ProDave]

What does your building control inspector say?  If (s)he says it is wrong, the builder might stand up and take notice.

[ProDave]

1 hour ago, Omnibuswoman said:

 

This joist has been rested on a scrap bit of OSB because the wall was built too short…

 

There is something more fundamentally wrong here.  That does NOT look like a load bearing wall, there should be a double header.  Anyone else care to confirm that or tell me it is okay?  

[joe90]

1 hour ago, Omnibuswoman said:

I’m not willing to accept living with the uncertainty just because it’s a ball ache to put things right. 

Too right, you’re  paying for it to be done correctly . 🤷‍♂️

[FuerteStu]

2 hours ago, Omnibuswoman said:

 

This joist has been rested on a scrap bit of OSB because the wall was built too short…

 

 

 

Not all hangers have been nailed to the joists. 

 

 

It also doesn't feel like there is enough fixings across this joint. 

 

Especially because it looks like there are no washers and the nail/screw is buried. 

 

What was the manufacturer's design for this connection? 

[Omnibuswoman]

1 hour ago, ProDave said:

What does your building control inspector say?  If (s)he says it is wrong, the builder might stand up and take notice.

I haven’t approached BC as yet, but will do so if the builder kicks up a stink about rectifying the issues. 

[Omnibuswoman]

11 minutes ago, FuerteStu said:

It also doesn't feel like there is enough fixings across this joint. 

 

Especially because it looks like there are no washers and the nail/screw is buried. 

 

What was the manufacturer's design for this connection? 

Well, the design is to have a continuous joist run the whole length of the house, and not be cut in two and stuck back together… but stiffening plates or joints should be fixed from each side equally, in a staggered formation - top right and bottom left from one side, and the same in reverse from the other. They haven’t done that, but the I-joist technician felt that was the least of our concerns 🤦‍♀️ He said I-joists are not meant to be cut and “scabbed” together, but it’s would be ok if there was a blocking plate in place between the joists (perpendicular to the direction they run) holding the joists straight. 

[Omnibuswoman]

1 hour ago, ProDave said:

There is something more fundamentally wrong here.  That does NOT look like a load bearing wall, there should be a double header.  Anyone else care to confirm that or tell me it is okay?  

I’ve checked the structural engineer’s drawings and the building control drawings, and while both show a cross section of the wall build-up neither shows the top or sole plate. So

 

I can’t say if they should have a double top plate or not. What I can say is that my workshop, which I built, has a double top plate at one side, and a quadruple one at the other side. My (former builder) uncle reckoned I could have built a second storey on top if I wanted to 😂

[Omnibuswoman]

[SteamyTea]

12 hours ago, Omnibuswoman said:

the supporting walls that sit above each other are not, in fact, sat above each other.

Is that because someone measured incorrectly?

 

The joists twist may or may not be a problem.  Ideally the forces need to go directly though the web, the greater the twist, the less load the joist can take, which causes buckling.  Buckling tends to be a catastrophic failure, not just a bit of extra 'bounce'.  This is because as the sin of the angle increases, the sideward forces increase (or is it the cosine, makes no difference, it is the angle that is important).

 

I would not be happy (structurally) with walls in the wrong place, twisted joists and brackets not fitted right.

You seem to be doing the right things in involving the manufacturer, builder and possibly a SE.

[Omnibuswoman]

Thanks Steamy. This is just what the technical manager explained yesterday - about the risk of failure by the joists not bearing the forces in the correct plane, and because of the supporting walls not sitting directly atop each other. The joists simply won’t function as they should and this could cause catastrophic joist failure. 
 

I’ve drafted and polished the email to the builder. Will see what he has to say in response….

[SteamyTea]

7 minutes ago, Omnibuswoman said:

polished the email

Will it be worth more with a shiny coat on it.

[Omnibuswoman]

8 minutes ago, SteamyTea said:

Will it be worth more with a shiny coat on it.

Most definitely!!

[Mr Punter]

I think you would normally have solid full height blocking between the joists at the wall junction, maybe x 2.  The scraps of OSB don't help as I think it needs a continuous bearing.  Why did he not just run the OSB all the way along?  If the decking is glued to the joists you may need to move the bottom of the joists to get them upright.  I guess they are just nailed?

 

I would want this agreed with your SE.

[ProDave]

This is how ours were done

 

 

Short sections of I beam came with the kit to go in between the main ibeams where they rested on a supporting wall.  They did not fill in the web, but that might be because our beams came made up as 11 metre long beams to span the entire length of the house resting on supporting walls on the way, so no joint between separate ibeams as you have in your case.

[Omnibuswoman]

@ProDave ours were meant to be continuous, but somewhere along the way someone decided to cut them and then stick them back together…!!

The solution to the twisting issue is what you have - I-joist pieces or solid LVL plates between each joist. That’s the design detail that should have been built in from the start. 

[Kelvin]

If this is wrong what else is wrong. I had an issue I identified. I got an independent SE to come and look at that issue and he identified several more. Get an SE in to do a review of the whole building. 

[Omnibuswoman]

This is our biggest concern - what can we not see that might have been botched… we’ve pored over the photos we took as the build progressed, just to check that the images match the plans. It has severely knocked our confidence in the builder’s skill and attention to detail (which was the key factor in choosing him!), and his general *sucks teeth* “maaah, should be alright” manner when things are pointed out is even more worrying and annoying. 
 

I’m sure many of you will have now read the Grenfell report which is a very good illustration of how badly things can go wrong, in ways people cannot imagine, when there is a lack of attention to getting things right. I am sure that the temptation is to think “it couldn’t happen” when something like joist failure is mentioned, but it could happen, if the right set of failures occur. This is why we pay structural engineers to design things!!

[saveasteading]

Agreed as above. The bco won't necessarily know all these things, and doesn't appear to have spotted errors to date.

Are you holding payments? Do so..it concentrates the mind.

Have you put in writing that the work is unacceptable? Do so.

An email will do for now.

These things are wrong, you insist hheg are put right within the next x days. No payment until then AND you will pursue them for any further cost in rectifying the works.

Lawyers can do the same later.

It is horrible and unpleasant but essential.

You can limit and phase costs by first requesting an inspection and verbal report. 

[Kelvin]

In my case the SE (who is on here, we’re in Scotland) wrote a detailed report. This was sent to the architect, their builder, and their SE who did the original structural design. It concentrated everyone’s mind to address the issues. 

Edited September 8 by Kelvin

[ProDave]

9 hours ago, Omnibuswoman said:

@ProDave ours were meant to be continuous, but somewhere along the way someone decided to cut them and then stick them back together…!!

The solution to the twisting issue is what you have - I-joist pieces or solid LVL plates between each joist. That’s the design detail that should have been built in from the start. 

Oh dear.  Why on earth would they cut continuous long beams?

 

As others have said.  Halt any more work and any more payments and get BCO and if necessary a SE to look at what has been done.

 

In an ideal world it would all be re done, but now it has been built up on top of those joists the easiest solution is likely to be to get a SE to specify exactly what to do to make the present work safe and stable, and then watch them like a hawk to ensure they do that exactly, even things like using the screws or nails that the SE specifies, not what happens to be in the back of the van.

 

P.S our joists also have more sections of I beam at mid span acting as noggins as well as those in my photograph above the bearing points.

[Oz07]

Be okay if was just a partition but that looks poor for a load bearing stud. I can't believe the cut in the middle of joist is designed like that. How many are cut like that? Whats the bottom of that stud sitting on, is the floor below load bearing?