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ICF Opening Spans Achievable


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Hi Everyone,

 

Amazing forum here and so much information by all thank you so much (I've enjoyed endless scrolling!).

 

I know it is dependent on engineer but I am just looking at what spans is available above sliding door openings (Pre-Planning Stage in Ireland).

 

I have a 5m opening and was wondering what height of concrete and rebar is needed above the opening? It is bungalow with just roof load above head of door.

 

Would anyone have a something similar and to that end would anyone be willing to send me their engineers drawings of ICF Walls and Roofs.

 

Thanks in advance,

 

Brian

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Thanks Guys for comments.

 

I didn't know the steel could be encased within the ICF, thats great (I like that the airtightness element of the concrete can continue through).

 

Is the steel simply supported by the webs of the ICF blocks? Or how is it held in place?

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2 minutes ago, Brian Ireland said:

...

Is the steel simply supported by the webs of the ICF blocks? 

 

4 meters plus a bit like this (in Durisol). Blocks laid on edge and cut open at the top - (called a soldier course) . Look at the pool of light at the far end of the beam ...

20170707_130603.thumb.jpg.905a23f38ab4d8dedf169e85777600a1.jpg

 

 it looked like this where two beams crossed (met? ... dunno the technical term). The lower beam is the one shown above.

20170708_084807.thumb.jpg.7bef1b2af9670c9614f2d98a5f3f7b21.jpg

 

Then the whole shooting match and caboodle was encased in very sloppy concrete

 

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If you can get an RSJ that fits within the block, for example a 150 wide beam could fit inside a 6" core block (Nudura forms) and sit on pockets cast in the concrete at either side of the opening.  The RSJ can then be packed out and clad with the same ICF.

 

5m is do-able with concrete but worth it? I'm not sure.

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14 minutes ago, Brian Ireland said:

Thanks Guys for comments.

 

I didn't know the steel could be encased within the ICF, thats great (I like that the airtightness element of the concrete can continue through).

 

Is the steel simply supported by the webs of the ICF blocks? Or how is it held in place?

 

Yes, as long as you have at least 25mm all around for concrete coverage. We've not poured that bit yet and I'm not sure how the concrete is going to get around the steel.... We had something similare in the basement but they didnt form ICF around it, instead they'll fix EPS to the beam.

 

The beam will sit on the concrete piers indicated on the drawing. It will also be welded to the rebar.

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You can do this also with rebar, depending on what you're supporting above. I have a few large openings - lowest floor has a 6m span though above this is a roof terrace  with a parapet wall over the sliding door opening so this is not the same as a sliding door with 2 more floors of wall resting on it. It has a fair amount of rebar and may have been quicker so maybe similar price using a beam! Not sure how this may compare to a roof loading. Lots of possibilities and may also depend on the void thickness in your ICF to see how much rebar could usefully be utilised there (for info mine are 200mm).

 

Edited by Adam2
typo
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I have a few big openings, 5.3m all done in icf with reinforcement in the concrete, I suggested to my engineer about installing a rsj into the core of the icf, he really didn’t like that idea and said you cannot get good consolidation of the concrete around the steel especially in the web. 

So you would need to make sure the steel is doing the job on its without the concrete assisting it. 

 

All mine where 12 and 16mm bars with links every 150mm, very fiddly to tie up as you needed hands like a  5 year old to get in between all the steel. 8250264C-9780-4EE2-BB32-6A86E79C2D3C.thumb.jpeg.2a8bd0d27cb536929c69d1007e4bc1d7.jpeg

Edited by Russell griffiths
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1 hour ago, Russell griffiths said:

...

I suggested to my engineer about installing a rsj into the core of the icf, he really didn’t like that idea and said you cannot get good consolidation of the concrete around the steel especially in the web. 

...

 

We 'solved'  (?) that problem by making sure that the slump was very low (high?) ... very runny. Weak Scotch broth the Durisol people like to call it.  

As luck would have it, a few months after it was cast,  the beam had an interesting test - a good few tonnes of Durisol fell 30 feet onto it. (The beam is just out of site above the Acrows on the left hand side.)

20170719_055031.thumb.jpg.7d6fc1e61589a223813cc75e15a604df.jpg.d8ff4b87ae26b9593fc50954778f8237.jpg

Nothing appears to have moved - yet.

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2 hours ago, Russell griffiths said:

I have a few big openings, 5.3m all done in icf with reinforcement in the concrete, I suggested to my engineer about installing a rsj into the core of the icf, he really didn’t like that idea and said you cannot get good consolidation of the concrete around the steel especially in the web. 

So you would need to make sure the steel is doing the job on its without the concrete assisting it. 

 

All mine where 12 and 16mm bars with links every 150mm, very fiddly to tie up as you needed hands like a  5 year old to get in between all the steel. 8250264C-9780-4EE2-BB32-6A86E79C2D3C.thumb.jpeg.2a8bd0d27cb536929c69d1007e4bc1d7.jpeg

@Russell griffiths That looks good. Maybe my small hands might come in useful on this build after all. Would you engineers drawings you could PM me so i could get an idea.

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17 hours ago, Adam2 said:

You can do this also with rebar, depending on what you're supporting above. I have a few large openings - lowest floor has a 6m span though above this is a roof terrace  with a parapet wall over the sliding door opening so this is not the same as a sliding door with 2 more floors of wall resting on it. It has a fair amount of rebar and may have been quicker so maybe similar price using a beam! Not sure how this may compare to a roof loading. Lots of possibilities and may also depend on the void thickness in your ICF to see how much rebar could usefully be utilised there (for info mine are 200mm).

 

 

Roof loading is probably a bit more.

Does all suppliers offer a 200mm core?

Assume with a 200mm core bigger spans are achievable.

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BBB8234C-1E3D-4D05-AC03-01D7D5ABA3E6.thumb.jpeg.4a8e6c10cff3acba437ff14e0e08ac37.jpeg

 

if you look at the three windows up high, when I asked the engineer to design the steel for this I told him I hadn’t made my mind up on window sizes, so the columns between the windows might change, so he designed it so that no columns where actually needed. 

So in-effect all three of those windows could be one, which would put the opening at something like 5.8m.  

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On 16/03/2021 at 11:00, Brian Ireland said:

Roof loading is probably a bit more.

Does all suppliers offer a 200mm core?

Assume with a 200mm core bigger spans are achievable.

I don’t think the width is as important as the depth, it’s the depth of a beam that provides most of the strength. 

 

I have a steel beam holding up my roof roof that is something like 147mm wide but 450mm deep. 

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