Big cracks in loft after open plan kitchen (merged threads)

Hi

Home owner in need of guidance as soon as possible please. I am no bulding expert so excuse any technical ignorance.

We have a terraced town house and had an open plan kitchen project completed July 2019. It involved the removal of an entire 6m wall on the side return, then replacing it with a 6m girder. We’ve had an architect, structural engineer & seemingly decent team of builders involved so had no reason to think anything would go wrong.

Following the removal of the props we saw cracks around windows on first floor above the open plan area and some cracks in corner of the bedroom also above. These were what we were told to expect so they were plastered over & for several months we’ve seen no return of cracking until recently. We also noticed soon after that the landing above the open plan area now sloped a little from party wall with neighbours down into bathroom, then up again to the wall above the girder. I got the structural engineer back to look at this and he concluded it was all normal with a house this age type of work (though it has always alarmed me that the floor now did this as you can feel it dip as you walk along the landing).

All remained the same until about a month ago when I noticed a crack in first floor wall in a new place above stairwell. I went up to the loft yesterday to check it and saw what looks like a pretty big crack in the party wall with neighbors loft (see image) a little further down the loft an old chimney breast that remains in the loft has also cracked in 2 places.

I can’t say how long the loft cracks have been there but my 2 yr old son has his room above the open plan area which makes me I be worried about this and what should I do?

Cheers

For a more rapid and helpful response, send this post to the 'Building' section on DiyNOT.

... or get a structural engineer or similar to inspect the house.

Ho sette!
Get the expertise in.
The all wall is moving and it shouldn't.

That's a tad disturbing- with that much drop on the chimney breast you'd expect to see some cracking in the external wall. Have you checked the new beam is still straight and level (tape measure to the floor centre and each end or a long level). I would agree that that chimney is not normal or acceptable- get the experts back in (or at least email that pic to the SE & see what they have to say). Were Building Control involved?

Thanks all

oldbutnotdead - yes building regs were involved

should i get the same SE in?

if this turns out to be a major & costly fault, who typically will cover the cost?

regards

mike

Oh good.
Yes to start with get back onto the original SE.
Get your tape measure out.
If the beam has deflected (bent) more than is permitted then the SE has some questions to answer. If the padstones have failed or the beam wasn't installed properly then the builder needs bringing back in.
Shame you don't have any Before pics (or was there a Party Wall award/survey?)
If your SE fobs you off then consider getting building control back in- they hopefully can advise how best to determine what has happened (you will have to expose the beam in places)
Just to make it clear- is that chimney breast with the big crack down the middle of it directly above the middle of the beam? Does the chimney breast continue down into the bedroom below or had it been removed?

Hi

Home owner in need of guidance as soon as possible please. I am no building expert so excuse any technical ignorance.

We have a terraced town house and had an open plan kitchen project completed July 2019. It involved the removal of an entire 6m wall on the side return, then replacing it with a 6m girder. We’ve had an architect, structural engineer & seemingly decent team of builders involved so had no reason to think anything would go wrong.

Following the removal of the props we saw cracks around windows on first floor above the open plan area and some cracks in corner of the bedroom also above. These were what we were told to expect so they were plastered over & for several months we’ve seen no return of cracking until recently. We also noticed soon after that the landing above the open plan area now sloped a little from party wall with neighbours down into bathroom, then up again to the wall above the girder. I got the structural engineer back to look at this and he concluded it was all normal with a house this age type of work (though it has always alarmed me that the floor now did this as you can feel it dip as you walk along the landing).

All remained the same until about a month ago when I noticed a crack in first floor wall in a new place above stairwell. I went up to the loft yesterday to check it and saw what looks like a pretty big crack in the party wall with neighbors loft (see image) a little further down the loft an old chimney breast that remains in the loft has also cracked in 2 places.

I can’t say how long the loft cracks have been there but my 2 yr old son has his room above the open plan area which makes me I be worried about this and what should I do? i'm also terrified we might have to vacate or lose vast sums of money on repair or the value of the house might suffer too.

We are of course insured & had building regs do their bit.

Please help

Thankyou so much for replying so quick

The beam is hidden by a false ceiling created to both hide the beam & allow for electrics + a toilet vent. When i asked the SE to re-attend to address the slumping floor etc he measured the false ceiling which i thought was odd as even i figured that wasn't a true measure of whether the beams angle. Fyi the beam is not one beam, it is 2 bolted together as the builder realised a 6m one would be too heavy to install. Which i also thought odd as none of the professionals involved considered this until the builder realised it was too heavy, he even had to absorb the cost of the 2 beams as the 1st one had been built already apparently.

I've attached 2 pics of the same view down the side return, plus closer images of where the 2 beams we re welded together and the beam that supports the corner

The chimney is in the middle, and yes there is a fireplace still beneath it on the 1st floor, the gorund floor portion was removed before we moved in, not sure when

thankyou

m

Interesting.
First one- unless the SE was notified in advance about the mod to the beams then he's off the hook for liability (yes manhandling a beam that size would have been a tad tricky but mechanical lifting aids do exist).Poor design having that pillar in the middle of the window but there we go. The beam certainly looks chunky enough and the splices look proper as well but see above....
Second one- the badly cracked chimney is on the party wall yes? So under the end of the crossbeams rather than midspan on main beam? Was there any evidence of support to the chimney breast within the floor when you had it exposed (suspect the answer is no, not the end of the world). Any sign of cracking in the chimney breast below that massive crack/drop?
Your 3rd pic is a bit of a giveaway- the beam would normally be hard up under the brickwork, any gaps packed with slate. Hard to make out the detail of the floor joists but they appear to be above the main beam so again would have room to move if the wall hasn't been packed properly, the midspan blocking doesn't look anything special.
The sag in the floor is a bit of a concern- the fact that it comes up to level on top of the main beam is a better sign though. Presumably there was another wall where the crossbeams are now (the 2 beams side by side)- if the joists haven't been properly supported there then that would explain the sag (the joists are running parallel to the main beam so can't be supported by it).
If the beams have been encased with dot and dab plasterboard (a standard technique) then the plasterboard would follow the line of any deformation of the beam so measuring to the boards can be valid (if it was boxed in with timber then that's another matter)
I suspect you're going to end up having to make some holes in the ceiling to see what has actually happened....in terms of resale value your baggy floor will put people off as will that massive crack in the chimney. I don't think the place is going to fall down but it definitely warrants some investigation. I wouldn't expect noticeable floor sag to be part of a job like that- have you measured the drop? (long bit of stick across the baggy floor, measure the gap under the middle of the stick)

Hi Oldbutnotdead


Yes I’m told the SE was notified & did the calculations for the builder to ensure it could bear the same weight as 1 single beam.


Yes the chimney emerges from the party wall. The party wall goes all the way down to foundations and as far as I know hasn’t been tampered with. If you looked directly down on the house the chimney would indeed be roughly above the crossbeams rather than across the main beam. In terms of support there used to be an archway in the kitchen that I think sat roughly in place of the ground floor section of the chimney. The arch was removed as part of the project and I guess the cross beam is in its place? What sits within the floor I couldn’t say. If you are referring to the massive crack on the party wall in the loft then yes there are cracks in the wallpaper beneath it – this was why I went up to investigate the loft and the horror began. The chimney breast cracks in the loft I think have continued into our bathroom as there is one that continues along the same angle in roughly the same place below it so both sets of cracks in the loft appear to have continued well in to first floor.


The floor sag has been there since the acro props got removed and has been a bitterly disappointing result of the project, the arch was what was beneath the double red cross beams.


I’m fairly sure it is plasterboard encasing the beam which is a relief to hear that it can still be measured, even with my eye I can see it has sagged but the SE did forewarn me about it. Frankly had I known about the sagging of the floor I would have insisted that a further pillar / column was installed in the middle of the main beam – but I don’t know if that would have prevented it.


Thankyou for all this, I have been really distressed about this as all of our assets are in the house and I have been pretty sleep deprived since Sunday, so it is really useful to have someone so willing to help at short notice and I greatly appreciate it. Are you in the trade then?


I will contact the SE today


m

1. Regarding the bolted splice; did the fabricator supply the correct bolts? Connections such as the one you have are known as 'slip-critical'; ordinary bolts will not hold without slipping slightly no matter how tight the builder gets them, and the beam deflects more than it should. The bolts have to be a special kind known as 'high-strength friction grip bolts' (HSFG bolts). These may be shown on the drawings, but might not have been used on site.

2. Deflection; the SE was right to point out that there will be some deflection (all beams, without exception, deflect under load). There are limits specified in design codes as to how much deflection is acceptable under the 'live load', ie the weight of furniture, people and things we put into our houses. But there is no specified limit to how much deflection should be allowed for the weight of the structure itself (the 'dead load') - this is down to engineering judgment and experience. (There was a case on this forum a few years ago where an SE had forgotten to account for dead load deflection, and the excessive deflection prevented new bifold doors from working). Ask the SE what numerical allowance was made for dead-load deflection.

3. When previous owners removed the chimney in the kitchen (but left the chimney breast in the bedroom?), they may have just bodged some support to the remaining chimney within the thickness of the floor. This might have been OK normally, but could have been impacted by the alterations.

4. The cracks may not be the end of the world and it's important to remember that older house are often built with softer bricks and softer
lime mortar, generally necessitating bigger than average padstones to spread the load at the end of the beams; it's inevitable that the house will move a little bit after such major surgery. In general, it's a fact that cracking above the level of a beam is usually not a serious matter, but cracking below beam level can be more serious, suggesting bearing- or foundation problems. What would also be of concern is settlement of the pad under the post; if this has settled slightly, it will result in a slight levering effect on the opposite ends of the beams, which causes cracking further away from the post.

PS, the beam should not have been painted in the vicinity of the splice plates as it considerably reduces friction and negates the clamping effect of the bolts.
Also, it's not a brilliant idea to have the splice at the point where the incoming beams are connected.

Just looking at the beam splice I would have thought the flange slice would have been bigger?

catlad said:

Just looking at the beam splice I would have thought the flange slice would have been bigger?

Click to expand...

I wonder if you might be confusing the flange- and web plates.
The flange plates are the big ones above and below the beam; the small one in the middle is the web plate. This is usually a lot smaller
and with fewer bolts because it is only taking the shear force at that part of the beam, which is usually low relative to the force in the flange plates.

Mike1801Mike said:

Hi Oldbutnotdead


Yes I’m told the SE was notified & did the calculations for the builder to ensure it could bear the same weight as 1 single beam.

Click to expand...

Oh good, you should have an additional sheet in your file from the SE specifying the variation to the original calculations

Mike1801Mike said:

Yes the chimney emerges from the party wall. The party wall goes all the way down to foundations and as far as I know hasn’t been tampered with.

Click to expand...

Couldn't tell from the pics- are the crossbeams set in the party wall or is there a big lump of C bolted to the wall & beams set on it? Not critical to be honest but be aware that the party wall will be taking load from those crossbeams

Mike1801Mike said:

If you looked directly down on the house the chimney would indeed be roughly above the crossbeams rather than across the main beam. In terms of support there used to be an archway in the kitchen that I think sat roughly in place of the ground floor section of the chimney. The arch was removed as part of the project and I guess the cross beam is in its place? What sits within the floor I couldn’t say. If you are referring to the massive crack on the party wall in the loft then yes there are cracks in the wallpaper beneath it – this was why I went up to investigate the loft and the horror began. The chimney breast cracks in the loft I think have continued into our bathroom as there is one that continues along the same angle in roughly the same place below it so both sets of cracks in the loft appear to have continued well in to first floor.

Click to expand...

I suspect the same as @tony1851 - a previous inhabitant junked the ground floor chimney breast and didn't bother putting any additional support in for the 1st floor breast. The general battering the house has received during this project has caused that breast to notice that it isn't supported by anything apart from friction so it has sunk a bit. That crossbeam is also not supporting your landing floor properly (if I've understood the plans correctly)- I also suspect if you exposed the top of those beams you'd find some fresh air between joists and beams. Yes beams deflect but you shouldn't end up with a noticeable gradient on your floor

Mike1801Mike said:

The floor sag has been there since the acro props got removed and has been a bitterly disappointing result of the project, the arch was what was beneath the double red cross beams.

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Yeah I can understand that disappointment. If I'm right (about the air gap above the crossbeams) then you MAY be able to jack the floors up (and I do mean jack, I've used a car jack before) and repack above the crossbeams BUT if any brickwork or rubble has settled above the joists then this may not be successful (if there's no wall above your crossbeams then you'll probably be OK but it is still a process to be undertaken cautiously

Mike1801Mike said:

I’m fairly sure it is plasterboard encasing the beam which is a relief to hear that it can still be measured, even with my eye I can see it has sagged but the SE did forewarn me about it. Frankly had I known about the sagging of the floor I would have insisted that a further pillar / column was installed in the middle of the main beam – but I don’t know if that would have prevented it.

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As far as I can tell from your pics the main beam isn't the problem- you said the floor drops from party wall to middle and rises when it gets to the main beam? With the joists running parallel to the main beam it won't be doing a lot of support to the floors above- the crossbeams are (should be) doing that job.

Mike1801Mike said:

Thankyou for all this, I have been really distressed about this as all of our assets are in the house and I have been pretty sleep deprived since Sunday, so it is really useful to have someone so willing to help at short notice and I greatly appreciate it. Are you in the trade then?


I will contact the SE today


m

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@tony1851 is the man for stuff like this- all I've got to offer is a Strength of Materials unit in a Materials Science degree (a long time ago) and a fair bit of practical experience. Gravity is not being your friend at the moment but (as tony said) cracking above the beams is less of an issue. If the splice in the main beam has stretched (due to friction issues detailed by him) the situation is not irretrievable- messy and expensive but not disastrous.