Steel beam (RSJ) is longer than wall to wall depth. Help!!!

[limitlessproperty]

So I'm installing 4 steel beams for my loft conversion, and I'm pretty much up to all of it apart from the actual manoeuvring of the beam into the pocket and onto the bearer plate.

The problem is, the wall span is 4650mm and the part walls either side are 150mm depth. This is a total of 4950mm. The steel beams by the structural engineer are to be 4800mm. We're in a mid terraced property so we are not able to cut into the wall more than 150mm.

When the crane is lifting in the beams, how are they going to be able to be inserted if the face of the party walls are narrower than the steel. The beam will get stuck as it's being turned into place. Right?

I got some instructions from the Party Wall Surveyor (who our difficult neighbours made us employ - has cost us a fortune) and he has said this...

3. On the non-chimney breast side, form a recess in the party wall half a brick deep (up to the centre of the party wall line) 1000 mm wide and 6 courses high for a pocket to allow steels to be angled into position and the spreader plate inserted.
4. On the chimney breast side, form a recess in the party wall half a brick deep (up to the centre of the party wall line) 500 wide (or the width of the specified steel spreader plate) and 6 courses high for the support pocket.

The depths of the property is only 7 meters, and cutting out that much brickwork from the wall is surely incredibly unsafe?! The ridge beam is no problem, however, the three floor beams are within very close proximity of each other, and cutting out that much of the brickwork will leave a large amount of brickwork above the cut-out exposed.

Is there an alternative - apart from cutting the beams in half. I hope there's someone out there who can help!!!

Regards.

 

[ree]

Fair enough in your coming on here for further advice, i think that you've done the right thing but there are too many unknowns in your post, and quite a few red flags.

It really needs a professional view on site - pay a local builder for a days work - someone to advise and supervise any steel insertion and installation.

AAMOI: if i read you correctly, you must not cut pockets in a chimney breast but perhaps you are not suggesting that.

If the steelwork has been specified by an engineer, and approved by BCO then that is how it must go in - you cannot start cutting and re-arranging it.

 

[tony1851]

If the beams have not yet been delivered, you could have them cut and spliced to make it easier.

Splices for beams commonly consist of bolted flange plates top and bottom, and bolted web plates. There is a cost to this as the splice has to be designed, and the fabricator will charge for the plates, drilling and bolts.

But the cost might be offset by not having to hire a crane - shorter beams can often be manhandled into place.

Untitled

• tony1851
• 7 Sep 2014
• 1

 

[Justin Passing]

@Limitlessproperty - please excuse me interrupting. I'm not a builder but am interested in your problem for my own application.
I'm not sure what's behind your question, maybe this partly answers, or perhaps my questions will prompt an answer to your own situation.

Is this right:
(1) Your distance between faces of the party walls (ie the gap) is 4650

(2)"part walls are 150mm depth" . Do you mean thickness? Surely not?
If (say) they're 9" solid walls how do you ensure going 150mm deep into them?
So how thick are the walls and how deep are you going into them?
4650 + 150 + 150 is 4950, but what is that a measure of, in your case?

If your gap (from (1) ) is 4650, are you aiming to have 75mm supported each end?

(3) What dimensions are your spreader plates?

I don't understand why you need such long slots/pockets inthe walls.
I think you're asking about the "swing" room you'll need:
If the gap is indeed 4650, and the beam is 4800 long
then dimension "A" is given by (about)
SQRT( (4800*4800) - (4650*4650) ) which is 1191

[More accurately, the beam needs room for its diagonal, which depends on its width.
Assuming 150mm, it would be
SQRT( (4800*4800) + (150*150) ) which is 4802.3
So it's only a couple of mm more, so forget it. ]

If you have a pocket in one wall which is 150mm deep, which I think you're suggesting, then you don't need ANY slot in the opposite wall to get the beam straight across. (Pocket in left wall not shown...). The beams in the sketch are all the same length. Twice the width of the beam looks plenty, for the length of the pocket on the right.

Why on earth you have to remove 6 courses of bricks I can't imagine.
And 1 metre long?? Surely only if the spreader plate is that long
Ree, Tony- why could they be suggesting such huge holes in the wall?

Untitled

• Justin Passing
• 7 Sep 2014
• 1

---
I can't help thinking you only want to go 75mm into each wall.

That means you DO need a long slot in the wall on the left.
Adding 3mm to the length of the beam to allow for its width, dimension A came to 866mm long, which is about a metre .

If your pocket on the right is 100mm deep (not 75), "A" comes down to 712mm, etc.
Does that help at all
?

 

[RonnyRaygun]

As Tony says.

Alternatively, cut the beam to 4600mm and insert two PFCs into the wall each end and bolt to the beam. You will need your SE to design the connection for you.