Kitchen Extension & Worrying Joist Query

[SmallPaulUK]

Hello all, I'm a new member to the forum, but have found it a great source of information over the past year having taken on a personal house renovation & extension project. I've done as much work as I possibly can on the renovation side of things, but now it's come to the extension I've got some professionals in. I do however have a concern over one aspect of the job so far which fundamentally feels wrong to me and was hoping to get a wider opinion:

The job has essentially involved removing the first floor rear wall of the house (two colossal RSJs have been put in) and a new extension built on the outside. The thing that concerns me is regarding the RSJ. It's all been done to structural engineer calcs, so the size of it doesn't bother me, it's the way that the second storey wall is supported that does. They initially propped the wall, took out the wall that was required and put the RSJs in the walls place. The outer skin of the cavity wall was then bricked up to take the load from the remaining wall onto the RSJ. The inner skin of the cavity wall however (the one that takes all of the weight of the house as i understand it) is only held up by the floor joists of the first floor! There is nothing between the floor joists keeping them in position (no noggins etc.), nor any bricks! The entire weight of the second storey wall is carried by the RSJ, through the floor joists and then point loaded onto the bottom bricks of the wall. I've added a picture where you can see the RSJ, the floor joists and the GAPS!

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• SmallPaulUK
• 16 Nov 2012
• 1

I've queried the builders about it and their response was "Don't worry, that's not going anywhere". We've obviously got building control involved so they're signing the work off as they go along and as far as I know they've not got a problem with it. It just seems fundamentally wrong to me however... What's to stop the floor joists rocking over and therefore bringing the external wall down? What happens to the wall if the joists absorb excess moisture and swell (or vice versa - contract?)? What happens if for some reason the joists were to go rotten (150yr old house and has experienced damp in the past...)? The ground floor room is destined to be a kitchen - If there's a fir and those joists burn through - the house is coming down!

It may just be me worrying too much and it may not actually be a problem, but like I said it feels wrong to me. Does anyone have any advice/ suggestions/ reassurance?

Thank you in advance!

 

[freddiemercurystwin]

What does the structural engineers detail show? Sounds like a cock up to me, if the beam is not wide enough for both skins a leg is welded onto the bottom flange to provide a shelf for the outer skin to sit on. Or two beams can be used one under each skin.

 

[dhutch]

What does the structural engineers detail show? Sounds like a cock up to me, if the beam is not wide enough for both skins a leg is welded onto the bottom flange to provide a shelf for the outer skin to sit on. Or two beams can be used one under each skin.

Seems like there are two beams, one per skin, the photo showing the first under the inner skin, prior to te second beign fitted.

Whats under question is the fact the the inner rsj, as shown, is only under the floor joists, presumably with the wall sitting above them, but not brick infill down from the wall onto the rsj.

Not a builder, so cant comment on whats normally done, but too would have expected the wall to be build down back the rsj.

Daniel

 

[freddiemercurystwin]

I assumed things had progressed beyond the time when that photo was taken.

 

[theoldun]

There should be a brick beam infill between new steel and existing brickwork. This should be dry packed with moist sand and cement to form a solid joint between old and new.
You are right in all your concerns. Your builder is a bell end. Ditto your building control if they have seen it and approved it.
Curious about that concrete lintel in the foreground?
Might just pay you to post photo of concrete lintel and one of the inside of flank wall left hand end.
Regards oldun

 

[SmallPaulUK]

Apologies for not putting up more photos, but I was at work and didn't have access to any more. I'm at home now (at the furthest point away from the death wall!).

Here's a pic I took today, looking from the inside out - you can clearly see the joists & wall balanced precariously on top...

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• SmallPaulUK
• 16 Nov 2012
• 1

For wider interest, the lintel in the foreground of the previous picture is for the big frech doors

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• SmallPaulUK
• 16 Nov 2012
• 1

Cheers for the comments, it's making me feel more justified in my challenge to the builder, but making me worried about how much extra it's going to cost me! Now is the time to do it though as it's all still exposed. As with all of the work I'm having done, I just have to keep telling myself that it's a lot of money but it'll be worth it in the end!

 

[r896neo]

Are you seriously saying building control saw this and where happy with it? If so they are mental.

The other possibility is the builder lying to you that building control ok'd it.

 

[tony1851]

Go with the Oldun; it is not accepted practice to transmit that sort of load solely through joist-ends.
You need to raise this issue with your inspector (and if necessary with his boss) and get THEM to put your builder right.

 

[Deluks]

Those speedfit joints, will they end up being inaccessable? buried between floors?
Access hatch if it were me.

 

[noseall]

I wonder how much less force would be imparted on those joist ends should the gaps be filled in.

You would need a diligent builder to come along and take the time to pack semi-dry mortar into all the horizontal joints in order to be successful.

I guess that any further joist shrinkage would ensure the masonry tightens up a bit.

 

[SmallPaulUK]

I think I'll give my builder a call tomorrow to see what he has to say and if I don't get anywhere, I'll give building control a call on Monday. Thank you all for your comments.

 

[theoldun]

Surely nose, beam filling serves four purposes.
To hold joist in position and stop any warping or twisting.
To assist reducing air pressure escape.
To provide your lateral restraint
To transfer the load above the joists on to the load bearing masonry below, in this instance the beam.
At least, that is the way we see it and the way we would do it.
Regards oldun

 

[noseall]

Surely nose, beam filling serves four purposes.
To hold joist in position and stop any warping or twisting.
To assist reducing air pressure escape.
To provide your lateral restraint
To transfer the load above the joists on to the load bearing masonry below, in this instance the beam.
At least, that is the way we see it and the way we would do it.
Regards oldun

I'm not doubting the merits of filling in correctly merely pointing out the effects of a half hearted repair job.

Whilst i agree the job at best is shoddy, a rushed filling in may only be moderately better.

 

[noseall]

It would be hilarious if anyone ever wanted to remove those joists.....

 

[SmallPaulUK]

Well building control confirmed my fears today and basically said the gaps will need to be filled to pass building regs. the guy I spoke to on the phone was surprised the inspector didn't pick up on it last week but said they'll make a point of checking next time.
I spoke to the project manager today and he's said he'll get the work remedied as soon as he can. A satisfactory resolution from my point of view, but it worries me how many people wouldn't have noticed something like that and it would have just been left! Thanks again for the comments, it definitely have me the confidence to challenge the problem target than fettling like I was asking stupid questions.