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Frameless glass


Nooie

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Hello all, We are going to build a post and beam style house and want to use frameless double glazed glass panels on the front of the house to have floor to ceiling views. We helped someone do this on their house already, but now things have changed in building control so we can't do exactly as they have done. They had a run of angled steel top and bottom bolted to the house frame and the glass was bonded straight onto that with no thermal break. We need something as a thermal break though. Would it work to have something like this around the glass and then then bonded to the steel? Or how thick a material would we need?

 https://www.ironmongerydirect.co.uk/product/sealmaster-therm-a-flex-flexible-intumescent-strip-10-x-2-x-2100mm-black-pack-of-10-537401?vat=1&GSP=true&gad_source=1&gclid=CjwKCAjw65-zBhBkEiwAjrqRMNV-6W1xeeglve9hKNmcQYOFdTB6G-Vp69SfUE7zSbb3BVqoD7eDNxoCGN0QAvD_BwE

This is the sort of idea at the moment. 

 Glass fix.jpeg

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Thanks JohnMo, we are using greenheart timber as a frame and not oak. It's been reclaimed off a pier. Greenheart has 1% movement compared to steel with 10% and is also stronger than steel. Steel would probably be easier to work with though as green heart is hard on tools and saws.

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5 minutes ago, Nooie said:

Greenheart has 1% movement

That's still 10mm per metre. Plus the glass needs room to move. The examples for oak, the glass is secured by compression of EPDM and leaves everything some wiggle room, gives a water tight assembly and is easy to replace in 10 years time if the glazing unit looses it's argon and starts to fog up etc.

 

Would expect your assembly fixed and bonded would lead to a crack glazing unit.

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10 minutes ago, Nooie said:

I should have said thaat the windows aren't actually fixed to the green heart itself. The bottom will be fixed to concrete and the top will be fixed to steel which will then be fixed to softwood timber.

I tried to do this with our house, decided it wasn't worth the effort/risks so just got frames. The wooden frame takes away 30mm from the sight line, you don't notice it. Ours sit in front of a steel frame.17181186644702721577034459257592.thumb.jpg.7924ad81be62e7e23e4ae33d053238f8.jpg

 

Cold bridge 

Your area at the bottom of the window is a big cold bridge. You need to look at a continuous insulation line. So at the bottom I would add a layer of Compacfoam and bring in the meet the floor upstand (would make this at least 50mm thick). This will have enough strength to take the loads and remove the cold bridge. Position in the wall depth will depend on how your walls are insulated the window needs to straddle the insulation.

 

The concrete/block section needs a good look at as from a thermal design perspective is rubbish and will leak heat like a seize. And likely lead to mould.

 

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JohnMo, thanks for the reply. Any chance you could scribble a sketch of what you mean? I'm not a builder so having a bit of a struggle with the windows. I'm happy enough to do all the wood working and concrete, but thermal bridging and all that is new to me.

 

 

 

"Your area at the bottom of the window is a big cold bridge. You need to look at a continuous insulation line. So at the bottom I would add a layer of Compacfoam and bring in the meet the floor upstand (would make this at least 50mm thick). This will have enough strength to take the loads and remove the cold bridge. Position in the wall depth will depend on how your walls are insulated the window needs to straddle the insulation."

 

 

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32 minutes ago, Nooie said:

JohnMo, thanks for the reply. Any chance you could scribble a sketch of what you mean? I'm not a builder so having a bit of a struggle with the windows. I'm happy enough to do all the wood working and concrete, but thermal bridging and all that is new to me.

 

 

 

"Your area at the bottom of the window is a big cold bridge. You need to look at a continuous insulation line. So at the bottom I would add a layer of Compacfoam and bring in the meet the floor upstand (would make this at least 50mm thick). This will have enough strength to take the loads and remove the cold bridge. Position in the wall depth will depend on how your walls are insulated the window needs to straddle the insulation."

 

 

Couple of markups

1 this is a cold bridge, basically heat can find a way to cold as there is missing insulation.

Glassfix.thumb.jpeg.eedd7b957bb6652f7020e6a69607683e(1).jpeg.9587ef35eaf558f77bce7a94746f1591.jpeg

 

2 adding Compacfoam will remove cold bridge. As there is now not a uninsulated pathway from warm to cold. Compacfoam is also able to hold structurally.

Glassfix.thumb.jpeg.eedd7b957bb6652f7020e6a69607683e(2).jpeg.701cec2ad91d80c4c06fa2f5f646f108.jpeg

 

3. Your upstand unless quite thick is now a weak area heat will go down to the ground and outwards to atmosphere also. Upstand I'd around 50mm or more.

 

Glassfix.thumb.jpeg.eedd7b957bb6652f7020e6a69607683e(2)(1).jpeg.7c41c816afa71833ca05f832bac010a8.jpeg

 

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I noticed this post earlier but didn’t want to comment in case it came over too negative 

john is right in your cold bridge. 
TBH  that is a terrible design and you will suffer with bad condensation on the steel and the bottom of the glass. 
look at johns latest post and try and relate that to the rest of the design. 
 

anywhere you have a path for cold to come into contact with warm will be a place for condensation to form. 
 

you need to isolate all cold parts of the build, foundations, exterior walls, roof junctions. 
 

 

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21 minutes ago, Nooie said:

Thanks John and Russell for your replies. I will have a look and see what we can do.

 

Cheers.

 

Basics are

Any cross section of the house, take a pencil or your finger following the insulation if you need to lift the pencil or your finger, to keep following the insulation you have a cold bridge. Your glazing and doors are classed as insulation. Apply the same technique for the airtightness layer.

 

If you are lost, post drawings and ask.

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