OK Gents, I have precast slabs coming next week and have a conundrum I need help with. The attached photo it shows the rear of my house with has a covered patio which will also act as a balcony for the master bedroom. This will be achieved by using 200mm precast slabs spanning between the external leafs of the external wall and for the last 1.5 meters it will span between the lintels shown supported on the blockwork piers and the external leaf of the external wall.

 

So to my question do I need to put a Steel between the 2 piers to stop any movement towards or away from each other OR the fact that I will pour a monolithic slab on top of them which will be 100mm wider than the slabs at the rear and parallel between the piers with will bond them and should also stop any chance of sideways movement.

Apologies if this is a bit rambling and doesn't make sense but it one of those things is very clear to me but I keep ping pinging between my decision and the time is NOW.

Is this not a question for your structural engineer?

Can you post some of the SE's drawings and a couple of elevetion drawings? Are you trying to go off piste here?

 

Advise you don't go off and do your own thing as there is much to consider.

 

 

Surely this is a matter of structural engineering, which nobody apart from your SE (and possibly @Gus if he had ALL the details) could answer.

I don't have any SE drawings that show anything bar steel in the roof , I can post elevations but they show even less detail about the porch. 

I can get one of the SE's at work to have a look at it but I want to settle my head on it first

 

Side elevation

Rear elevation

Snip of precast drawing

It isn't for you to dabble with what the SE has shown. If it isn't clear then you mast ask the SE, not us who don't know the details or context.

These columns look a bit  flimsy but the planks might retain them sufficiently if very precisely and properly connected to form an integrated structure.

We are not here to do that design, cannot, and would not.

 

And adding a steel is not necessarily going to make it stronger: structures can be complex.

 

Oh,  and btw what makes you think this is 'gents' only?

We had a similar scenario and the SE wanted a 80mm SHS wind post on the ends of the walls. We also dowelled and grouted the precast slabs. You'll definitely need something similar. You elevation drawing shows a brick head above the windows? Is that under neath the slab? How will you do this detail?

7 minutes ago, Conor said:

You elevation drawing shows a brick head above the windows? Is that under neath the slab? How will you do this detail?

 

+1

 

Perhaps design the steel to take brick/stone slips?

Edited July 27, 20224 yr by Temp

Also needs details on how the slab will be insulated. Presumably the insulation is going on top? Floor levels vs balcony? If its going under then is there enough height above the side windows?

Is this an 'add on'?  Can't see those pillars on the elevation drawings, or am I missing something?

The drawings only show a cantilevered balcony about 1.0m deep, not the 1.5m portico arrangement you have built.

 

I can't see any issue with the piers moving once you land the planks on them, but can you run it past your SE?

Slab drawing appears to show dowels, and friction alone would do most of the work.

 

Check with your SE but an additional steel would be overkill I think.