Posted By jonr on 10 Mar 2013 05:18 PM
I'm not mocking it, although the claims might be somewhat exaggerated. Thermal bridging is an issue and the typical cantilevered balcony IS like a fin on a heat sink.

I'd also look at a diagonal cable running from the outer edge of the balcony back to an anchor on the wall (ie, not a cantilever). Or use a corbel. Or cover the entire balcony with foam (perhaps with another layer of concrete over it).

I have a 5x5 cantilevered balcony that it would work great to thermally break it. Nobody else I talked to could figure out how to thermally break it. Thermal bridging is considered the norm and nobody really cares about it. I could leave it alone and let it thermally bridge that 5 foot area but for a couple hundred dollars, it seems like a better result than having a cold floor near the balcony door.

A 2nd story or higher NON-cantilevered balcony is also somewhat difficult to thermally break.

Let's say you used InsulDeck for the 2nd floor and then you had the 2nd floor area turn into an exterior balcony that is supported by a concrete column & beam below. The bottom side is insulated but the top of the slab is exposed to the elements. The product would also work for the area that transitions from the exterior balcony to the interior.

Posted By Lbear on 10 Mar 2013 06:16 PM

Posted By jonr on 10 Mar 2013 05:18 PM
I'm not mocking it, although the claims might be somewhat exaggerated. Thermal bridging is an issue and the typical cantilevered balcony IS like a fin on a heat sink.

I'd also look at a diagonal cable running from the outer edge of the balcony back to an anchor on the wall (ie, not a cantilever). Or use a corbel. Or cover the entire balcony with foam (perhaps with another layer of concrete over it).

I have a 5x5 cantilevered balcony that it would work great to thermally break it. Nobody else I talked to could figure out how to thermally break it. Thermal bridging is considered the norm and nobody really cares about it. I could leave it alone and let it thermally bridge that 5 foot area but for a couple hundred dollars, it seems like a better result than having a cold floor near the balcony door.

A 2nd story or higher NON-cantilevered balcony is also somewhat difficult to thermally break.

Let's say you used InsulDeck for the 2nd floor and then you had the 2nd floor area turn into an exterior balcony that is supported by a concrete column & beam below. The bottom side is insulated but the top of the slab is exposed to the elements. The product would also work for the area that transitions from the exterior balcony to the interior.

Actually Lbear, the supported cantilever I have dealt with many times and actually there is a simple solution. Where the transition from outside to inside takes place, provided you have bearing support below it, the slab is disconnected with a piece of foam. the rebar is continuous through the foam which will allow minimal heat/cold transfer, but not enough to justify the expense of Schoek's product in that area.

Posted By Chris Johnson on 10 Mar 2013 07:14 PM


Actually Lbear, the supported cantilever I have dealt with many times and actually there is a simple solution. Where the transition from outside to inside takes place, provided you have bearing support below it, the slab is disconnected with a piece of foam. the rebar is continuous through the foam which will allow minimal heat/cold transfer, but not enough to justify the expense of Schoek's product in that area.

If the balcony is supported from below, it is truly not "cantilevered".

When you run rebar through foam, how is that rebar held in tension inside of the foam and how is vertical shear force of the balcony slab transferred in a foam area that has no concrete? When you run rebar through the foam the strength of the rebar in compression is completely lost by substituting EPS for the concrete. Did the engineer sign off on allowing you to substitute concrete by using foam and running rebar through the middle of it?

During the "Construct Canada" show in Toronto, Canada on September 2012 when Schock introduced their product they said the most repeated comment by builders was, “Why change the way we build, Why now?”

Construct Canada

Here is the product being used in Beaver Barracks in Ottawa, Canada:

YouTube

Just to clarify, Schock is more than just some foam with rebar going through it:

The transverse force (vertical force from the balcony slab) is guided from the concrete into the bent edge of the tension rod. There it is divided into a tension component in the shear force rod and a pressure component in the HTE pressure module by resolution of a force (triangle of forces). On the ceiling side, the tensile force from the shear force rod is redirected in the bend and guided into the ceiling via the tension rod and the concrete. In order to ensure that the shear force rod is tensioned, Schöck Isokorb® must be installed in a manner that allows the shear force rod to run from the bottom outside to the top inside.  The maximum possible transverse force that can be transferred is called V_Rd.

You place the foam in the centre of the ICF wall where the thermal break needs to be, so with an 8" ICF wall, create a taper top on both sides to allow sufficient bearing, with the foam in the middle, rebar passing through the foam as well as bent dowels into the wall both side of the foam insert projecting into their respective sides of the slab. That's how it was dealt with and yes it was signed off and approved by an engineer. And no, this does not work on a true cantilever, some form of outside support is required the carry the massive load.

I have spoken with someone from the company today in Germany, I have sent him plans for a project I am working on with 18 balconies. When answers come in I will post. If this system works as I predict/anticipate it will, it may very well be a solution for a problem that does really exist.

Posted By Chris Johnson on 11 Mar 2013 08:39 PM
You place the foam in the centre of the ICF wall where the thermal break needs to be, so with an 8" ICF wall, create a taper top on both sides to allow sufficient bearing, with the foam in the middle, rebar passing through the foam as well as bent dowels into the wall both side of the foam insert projecting into their respective sides of the slab. That's how it was dealt with and yes it was signed off and approved by an engineer. And no, this does not work on a true cantilever, some form of outside support is required the carry the massive load.

I have spoken with someone from the company today in Germany, I have sent him plans for a project I am working on with 18 balconies. When answers come in I will post. If this system works as I predict/anticipate it will, it may very well be a solution for a problem that does really exist.

So on a NON-cantilevered balcony, do you think it is NOT necessary to use the Schock thermal break and just use standard foam thermal break?

I will be interested to hear what they say and how this project proceeds.

Thanks for the info!

Looks like a good product.

For cantilevered or not, I would trust stainless steel over standard rebar because normal cracking allows for water infiltration (if deck is not covered and concrete is not regularly sealed) and then rust. Rust expands the concrete causing a cycle - more cracking and more leaks, etc.

I would at least use stainless ($$$$) at the balcony-structure connection point because when if fails, it's coming down and hope no one is below when it does. The deck should outlast the house or again it will either come down on its own or need to be torn down. But having a 200 year old concrete balcony outlast the house is probably not going to happen anyway. On that note, just enclose the balcony with wrap-around folding windows (like from NanaWall)!

Posted By sharter on 12 Mar 2013 11:28 AM
Looks like a good product.

For cantilevered or not, I would trust stainless steel over standard rebar because normal cracking allows for water infiltration (if deck is not covered and concrete is not regularly sealed) and then rust. Rust expands the concrete causing a cycle - more cracking and more leaks, etc.

Epoxy coated rebar is probably cheaper. That's what's being used in roadways these days, or where corrosion is sure to be an issue.

In theory, epoxy coated rebar is a very neat idea but in practice the coating is easily damaged which can lead to corrosion under the coating.  I think galvanized rebar will require less careful handling and installing but will cost more than uncoated rebar.

You guys want to see what happens when concrete leaks and allows water infiltration...on a roof top parking structure above a commercial building?

Google - Elliot Lake Mall Collapse - It's in northern Ontario, now the cause is technically still under investigation at the inquiry, but so far the leaked information has been water caused corrosion and failure in welded connections on beams holding up a suspended slab...but this was also built to code, passed and approved during the original construction phase. On going maintenance on the other hand, well I think that's another story and is going to bite someone in the rear end. Fortunately this is not the USA so lawsuits will be a little tamer in the way of awards for damages, 2 people did die, about 20 others suffered various degrees of injury.

And yes Lbear it was a non-cantilevered area I spoke of, the original plan was to cantilever but with the thermal break issue, we added perimeter walls to carry the load to allow a thermal break installation, otherwise we would have been forced to increase/dedicate additional in-floor heating tubes to try and combat the impending cold transfer, which would have eliminated the green building aspect of the project. And our method of thermal break worked as well as the Schoek product and much more cost effective (about $ 50.00 worth of EPS).

Posted By Chris Johnson on 12 Mar 2013 06:45 PM
You guys want to see what happens when concrete leaks and allows water infiltration...on a roof top parking structure above a commercial building?

Google - Elliot Lake Mall Collapse - It's in northern Ontario, now the cause is technically still under investigation at the inquiry, but so far the leaked information has been water caused corrosion and failure in welded connections on beams holding up a suspended slab...but this was also built to code, passed and approved during the original construction phase. On going maintenance on the other hand, well I think that's another story and is going to bite someone in the rear end. Fortunately this is not the USA so lawsuits will be a little tamer in the way of awards for damages, 2 people did die, about 20 others suffered various degrees of injury.

And yes Lbear it was a non-cantilevered area I spoke of, the original plan was to cantilever but with the thermal break issue, we added perimeter walls to carry the load to allow a thermal break installation, otherwise we would have been forced to increase/dedicate additional in-floor heating tubes to try and combat the impending cold transfer, which would have eliminated the green building aspect of the project. And our method of thermal break worked as well as the Schoek product and much more cost effective (about $ 50.00 worth of EPS).

What's a good concrete coating that seals/waterproofs the concrete but is friendly with EPS?

They make epoxy paints for garage floors but those are probably not suited for outdoor UV use.

In your neighbourhood, visit WhiteCap and see what they suggest

Well, I am at about $80 a ft for my project in material costs or $ 32,000.00 in real hard numbers, then I have about 10% in incidentals, engineering, etc. Now I'll present it to the developer

Posted By Chris Johnson on 14 Mar 2013 04:05 PM
Well, I am at about $80 a ft for my project in material costs or $ 32,000.00 in real hard numbers, then I have about 10% in incidentals, engineering, etc. Now I'll present it to the developer

So they got back with you and said the project is feasible?

This is for a cantilevered balcony?

Do they engineer it or must your site engineer do the calcs for the product?

I have not read everything fully yet...I need to sell the theory of the thermal break and it's inherent cost to the developer. Yes it is a fully cantilevered balcony, actually 18 of them in total. I believe it is a combination of their suggestions from their engineer and the EOR finalizing and stamping everything.

What's a good concrete coating that seals/waterproofs the concrete but is friendly with EPS?

Probably two part polyurethane.