Frameless glass windows - my design.

[Caversham Build]

Hi all,

 

i am cannot find a glazing supplier who can provide some nice looking, reasonably priced, frameless glazing. 

 

Most suppliers will not even speak to me as their minimum contract is 25000 some 30'000! I need two 800mm x 2500mm windows in between two facing brick returns. 

 

I have designed my own version of frameless glazing using sealed glazing units and rubber seals wedged into a channel in brickwork

 

Can someone please tell me why i cannot do it this way, why is is not  structurally suitable, or why it will endanger life or any other reason to not do it this way.

 

This is a new outbuilding  no more than 30sqm and built of substantially non combustible materials so not subject to building regulations.

 

thank you for your help!

 

 

 

 

[PeterW]

Got some monumental cold bridges in that design. No issue with what you’re proposing except for the fact you can never replace them if they get damaged. 
 

I would put them into a slim frame internally and step the internal brickwork back slightly so you can install them after the roof is on and also replace them in the future. 

[JohnMo]

Some basic questions

Have you checked you have allowed enough room for the glass thermal expansion and any settling of building at sides, bottom and top of glazing.

 

Do you need a weeping hole at bottom to prevent any water accumulation?

 

All you sizing looks tight for easy assembly, the rubber glued to the glazing may cause hang ups when trying to insert in to block work.

[Caversham Build]

3 hours ago, PeterW said:

Got some monumental cold bridges in that design. No issue with what you’re proposing except for the fact you can never replace them if they get damaged. 
 

I would put them into a slim frame internally and step the internal brickwork back slightly so you can install them after the roof is on and also replace them in the future. 

 

Hi PeterW thanks for taking the time to respond.

 

Are the monumental cold bridges the brick returns ? or the window wedged into the brick channel? or something else? If it's the brick work aesthetics have to come first unfortunately. If it's the glass perhaps i could use another material that insulates better instead of rubber ?

 

In terms of replacing a potentially broken glazing unit my plan was remove the rubber, cut the pane in half, remove it, then cut a bigger channel (deeper and wider in the brickwork enough to slide in a new pane and cover with a bigger finishing strip. grind off the internal top of the sill and then place new glass in and re seal - Any idea the lifespan of sealed glazing unit?

 

does stepping back the brick work mean not having a straight line on the return a bit like what i have drawn here attached?

 

thank you

[Caversham Build]

3 hours ago, JohnMo said:

Some basic questions

Have you checked you have allowed enough room for the glass thermal expansion and any settling of building at sides, bottom and top of glazing.

 

Do you need a weeping hole at bottom to prevent any water accumulation?

 

All you sizing looks tight for easy assembly, the rubber glued to the glazing may cause hang ups when trying to insert in to block work.

 

Hi JohnMo thank you for taking the time to respond,

 

Have you checked you have allowed enough room for the glass thermal expansion and any settling of building at sides, bottom and top of glazing.

 

No i've not allowed for expansion or settling, could you give me a rough guide figure?

 

All you sizing looks tight for easy assembly, the rubber glued to the glazing may cause hang ups when trying to insert in to block work.

 

i was planning to glue in the 3mm rubber strip onto the brickwork channel/dpm, then once i have lowered the window in from above, push it up against the 3mm rubber strip and wedge the 10mm rubber behind it. - should i give it more space anyway?

 

Do you need a weeping hole at bottom to prevent any water accumulation?

 

I'm not sure. do i? do you mean in the sealed glazing unit (i'm guessing not) or somewhere else? - where would the water accumulate?

 

squse all these amateur questions but i really am an amateur

 

thank you 

[JohnMo]

I have seen this may worth looking at

 

https://m.sessile-oak.co.uk/Resources/Glazing

 

There is a thread on here that looked, had a design, so may be worth a search.

 

Don't know any of the answers, but aware how unforgiving glass is.

 

Linear expansion coefficient is what you are looking at.  If you have a gap around the window at zero degrees, with the sun shine on the wall and the window, glass will expand so will the wall, closing gaps, you need enough space between the different pieces so they don't end up breaking the glass.

 

https://www.google.co.uk/amp/s/www.engineeringtoolbox.com/amp/linear-expansion-coefficients-d_95.html

[Jilly]

A local glazing company would supply double glazing casements if you give them measurements. How you use them is up to you, I suppose, but if everyone is saying you need a frame and you are an amateur by admission, I would be inclined to take note and modify your design. 

[Caversham Build]

Thank you for your input Jilly

 

Can anyone actually recommend a reasonably priced thin framed glazing unit / brand ? Everywhere i look the description is 'frameless' or 'minimal' frames or 'ultra thin frames' and the frames turn out to be minimum 60mm - i would be happy to put an internal frame on the brickwork if i could get the profile down to 30mm or less.

 

thanks 

[Caversham Build]

41 minutes ago, JohnMo said:

I have seen this may worth looking at

 

https://m.sessile-oak.co.uk/Resources/Glazing

 

 

 

this is interesting. so in theory if i can attach glazing bars to the brickwork (flush pointed) and line them with the epdm foam on both sides inside and out as per the diagram. This will allow me to mount the glass in between the two returns.   if i left my self 10 mm either side for an expansion then i could probably get away with a 20 - 300 mm profile. i would need metal glazing bars that i could screw into the wall and then finish with a strip. i guess this is essentially just thin framed glazing that i build myself right?

[Gus Potter]

Like the idea. But trying to mount glass almost directly into brick, drain it etc at the base is as others have pointed out fraught with potential issues. The brick line will vary a lot more than you think.

 

If you get a slender frame then on the inside can you mount slip bricks on a carrier and discertely fix. This way you can unscrew the slip bricks on the carrier to access the frame should the unit fail or just need maintenance.

 

@Onoff.. has had a go at this re his gate posts so you may get some ideas from his posts.

1 hour ago, Caversham Build said:

 Any idea the lifespan of sealed glazing unit?

Ah! Have seen windows with 10 year guarentee but the sealed units only 7.. in the fine print. It's a mine field this.. once you delve deep into the standards etc. One basic rule is that sealed units are not tested for any standing water at the base, that is why packing and drainage is vital if you want to make a case for replacement. I think that unless you get the detail right you'll be lucky to get a couple of years out the sealed units.

 

In terms of your lintel a 6.0mm thick plate is not going to cut the mustard. If you have plenty masonry above and it develops an arch then I would go for a 15mm thick S275 galvanised steel plate as a kick off., maybe 20 thk. You can look at stainless steel but the prices at the moment are bonkers. for stainless flats this thick.

 

 

 

 

[Caversham Build]

16 minutes ago, Gus Potter said:

 

In terms of your lintel a 6.0mm thick plate is not going to cut the mustard. If you have plenty masonry above and it develops an arch then I would go for a 15mm thick S275 galvanised steel plate as a kick off., maybe 20 thk. You can look at stainless steel but the prices at the moment are bonkers. for stainless flats this thick.

 

 

Ah man you're giving me sleepless nights! I had a structural engineer prove my design and she didn't raises any issues with the 6mm plate.  this particular lintel is carrying only about 25kg of weight above the window (about 6 - 8 imperial bricks)  -  i also have a 6mm plate welded to the underside of a cantilever beam beam to support around 100 - 150kg of masonry over a span of 4 m

 

 

[Gus Potter]

17 minutes ago, Caversham Build said:

 

Sleep well! You probably have enough masonry over the opening and to each side to form a properly butressed arch. Thus if you "very conservatively" project a 60 deg line up from the edge of the opening you form a triangle of masonry. This is the bit the steel needs to carry. If say brick and the perp ends (the vertical joint at the end of the brick) are fully filled then it will almost be self supporting over a small opening width.

 

@Caversham Build"I also have a 6mm plate welded to the underside of a cantilever beam beam to support around 100 - 150kg of masonry over a span of 4 m "

 

Cantilevers are a very different animal as are top bottom plates welded to beams as they can introduce significant buckling effects and torsion (twisting) effects respectively. It's a long explanation but if you have any concerns don't hesitate to raise this with the SE.

 

 

 

 

 

[Caversham Build]

Thanks for the help / advice everyone

 

here is my latest design, it means i would have a 25mm frame around the glass but i think the sightline on the glazing units are 12.5m anyway.

 

Again please do tell me why this design is not possible if you can 

 

I'm still tempted to try the original design, you only live once and we'll be knee deep in world war three soon. 

[saveasteading]

3 hours ago, Caversham Build said:

thermal expansion and any settling of building at sides, bottom and top of glazing.

 

Most buildings move more than people imagine, or like to think, mostly seasonally. Some movement allowance from brick to frame and then frame to glass allows for this.

Your proposal looks very solid.

[Caversham Build]

@saveasteading thanks. when you say my proposal looks solid, are you referring to my most recent 'internal frame' detail ? 

 

thank you 

[saveasteading]

12 hours ago, saveasteading said:

Your proposal looks very solid.

No I had not noticed the revised proposal, which seems much more tolerant to movement.

 

You will have to find a way of wedging the glass in tight to keep it in place as well as the weather out.

 

Also, a minor detail , is not to drill so close to brick edge.

 

I admire your enthusiasm and acceptance of challenge and risk. But isn't there some small standard window section that would do the same?

[Caversham Build]

20 minutes ago, saveasteading said:

No I had not noticed the revised proposal, which seems much more tolerant to movement.

 

You will have to find a way of wedging the glass in tight to keep it in place as well as the weather out.

 

Also, a minor detail , is not to drill so close to brick edge.

 

I admire your enthusiasm and acceptance of challenge and risk. But isn't there some small standard window section that would do the same?

 

thanks

 

please do point me int he direction of one, i cant seem to find any simple fixed glazing windows that have a simple thin frame like this 

[PaulJ-R]

I think a small aluminium channel would be a better solution. We had a similar request from an architect for a Rail Station a few years back

If:

1. Insulation/heat loss is of no concern

2. You are OK with having to smash the glass in case of future removal

3. The masonry is existing - already built

 

Then consider cutting a channel into the wall and fixing a small aluminium channel into the wall both sides, install your glass - 6mm toughened as a minimum, 10mm might be better. 

The channel will need to have enough depth to all the glass to go into one and then pass into the opposite. You will have to use silicone sealant on one of the faces to fix the glass location.

 

To source your materials look at wetroom glass shower partitions

 

I

[Mr Punter]

I have some frameless style glazing but it is not sealed unit it is 25mm laminated so no issues with misting.  They used an ali channel set into the brickwork so the ali is not visible.