Glass Balustrade thickness?

893bet

Hi, for my stairs I am planning on an oak handrail with glass balustrade. What thickness of glass should be used? Anyone with experience?

Metric Tensor

There's two codes of practice for this BS6180 and BS6262. Get your engineer to decipher them (they're not too bad but a little technical).

Take your engineer's figures and then approach one of the larger glass manufacturers. I can't name them here but there's one leading name in the country - won't be hard to find. Give them the figures and tell them you want glass thick enough for that loading.

They do staircases all the time but it might be unusual for a domestic client to approach them directly requesting such specific info but that's no reason not to do it right!

Is the stairs curved or straight? Curved glass for a stairs is pricey!!!

893bet

Thanks. Will have a look.

Sadly my engineer doesn't bother with that type of thing such as calculations. Rather he overspecs. E.g I ended up with 3 100mm box steel corner posts for a single story sunroom that support a single course of blocks and the roof. His words when I asked him "use 100mm box, will be plenty strong and save me doing the calculations".

If I ask him he will say 20mm glass probably.

The standard seems to be 10-12mm used. My runs will be short, broken by newel posts. Still want it done right though.

The glass supplier said 6mm should be fine!

Metric Tensor

A lot of it depends on the exact shape/layout of the stairs and how/what the glass is fixed to. It will have to carry very different loadings. I'm not going to go into structural details because it's not for this forum and anyway I don't know your specific circumstances but there is a big difference between:

This:
http://www.ialonet.gr/ialonet/uploads/images//glass_banisters/DSC02654.big.JPG


and this:
http://www.wilcoxfabrications.co.uk/images/Gallery-Images/Balustrades/balustrades-31.jpg

Best thing is to get someone to put their name to it in writing - that'll sort the men from the boys!

Gumbo

893bet wrote: »

Thanks. Will have a look.

Sadly my engineer doesn't bother with that type of thing such as calculations. Rather he overspecs. E.g I ended up with 3 100mm box steel corner posts for a single story sunroom that support a single course of blocks and the roof. His words when I asked him "use 100mm box, will be plenty strong and save me doing the calculations".

If I ask him he will say 20mm glass probably.

The standard seems to be 10-12mm used. My runs will be short, broken by newel posts. Still want it done right though.

The glass supplier said 6mm should be fine!

If I came across 6mm glass on a stairs on one of the sites I'm inspecting I would be sending a Section 11 request for calculations and/or certification from an engineer and/or the glad manufacturer that demonstrates that it complies with TGD Part K and the relevant BS / EN codes for safety glass (toughened etc).

6mm just seems thin. Your engineer really should be making more of an effort here. Is he the one signing off on the project?

893bet

I am not going to use 6. It will be 10mm min regardless if thinner would meet requirements.

Haven't seen the engineer since the roof was signed off....a long time ago. 16 months or more.

Johnnyhpipe

Just to note - Balustrades are defined as "non-structural" and if you have appointed the engineer under the terms of SE 9101 (which you likely have) then balustrade design is considered an "additional service" and is exclused from engineers role as permanent works designer on most standard engagements.

That said, he may be willing to assist you in this regard.

You havent said if you're going with a cantilever glass balustrade or if its just infill panels? If cantilever then its way too thin at 6mm!!!

893bet

It is just "infill". There will be an oak handrail and newel posts etc

My carpenter has told me to prepare to bend over in all directions for solid oak and glass. He is pushing for painted risers etc.

Similar to below but with a bullnose and nicer newel posts etc.

Gumbo

Johnnyhpipe wrote: »

Just to note - Balustrades are defined as "non-structural" and if you have appointed the engineer under the terms of SE 9101 (which you likely have) then balustrade design is considered an "additional service" and is exclused from engineers role as permanent works designer on most standard engagements.

That said, he may be willing to assist you in this regard.

You havent said if you're going with a cantilever glass balustrade or if its just infill panels? If cantilever then its way too thin at 6mm!!!

Johnny, I didn't mean that my post implies that the Engineer should do it for free, I thought the Engineer is signing off on the project as a whole and in compliance with Building and Planning Regulations, and if so then he must insist and ensure that they comply with the relevant codes and he must step in to design/over see them, imo of course.

ht9zni1gs28crp

893bet wrote: »

It is just "infill". There will be an oak handrail and newel posts etc

My carpenter has told me to prepare to bend over in all directions for solid oak and glass. He is pushing for painted risers etc.

Similar to below but with a bullnose and nicer newel posts etc.

I was pleasantly surprised at how decent out price was for Ash and Glass, similar to above but with no clamps. Those glass clamps are the work of the devil

It will be the Oak that drives the price up, not so much the glass....

893bet

miller_63 wrote: »

I was pleasantly surprised at how decent out price was for Ash and Glass, similar to above but with no clamps. Those glass clamps are the work of the devil

It will be the Oak that drives the price up, not so much the glass....

I am trying to get my wife away from clamps towards router grooves.

Can you post some pictures of your stairs? And price? Pm if you prefer

DOCARCH

893bet wrote: »

I am trying to get my wife away from clamps towards router grooves.

.....had to double check that I was still in C&P forum!

fatty pang

The loads (from BS 6180:2011) on infill panels in this instance (single family dwelling) will be 0.36kN/m 0.25kN, 0.5kN/m²
Pilkington provide a mechanical strength calculaters for IGU/window manufacturers to assist determining suitable thickness for specified loads. Taking a pane fixed; fully framed or 4 corner points or 2 full opposite edges - 6mm toughened glass will be adequate. As noted elsewhere the glass supplier having access to the Pilkington calculators or their Tech support would be able to provide confirmation of this to satisfy whomever is certifying compliance.

893bet

fatty pang wrote: »

The loads (from BS 6180:2011) on infill panels in this instance (single family dwelling) will be 0.36kN/m 0.25kN, 0.5kN/m²
Pilkington provide a mechanical strength calculaters for IGU/window manufacturers to assist determining suitable thickness for specified loads. Taking a pane fixed; fully framed or 4 corner points or 2 full opposite edges - 6mm toughened glass will be adequate. As noted elsewhere the glass supplier having access to the Pilkington calculators or their Tech support would be able to provide confirmation of this to satisfy whomever is certifying compliance.

Surely the loads depend on the size of the panels? Rather than how its held in place? I am planning on 4 clamps per panel.

I did find the below link which specifies the minimum load in a domestic setting to be 0.36kN/m and this equates to 12mm glass according to the table.

http://www.aluminox.co.uk/what-glass-thickness-do-i-need-in-my-frameless-balustrade-22-w.asp

Johnnyhpipe

893bet wrote: »

Surely the loads depend on the size of the panels? Rather than how its held in place? I am planning on 4 clamps per panel.

I did find the below link which specifies the minimum load in a domestic setting to be 0.36kN/m and this equates to 12mm glass according to the table.

http://www.aluminox.co.uk/what-glass-thickness-do-i-need-in-my-frameless-balustrade-22-w.asp

Load per m doesn't depend on panel size as its specified in kN/m and kN/m sq. The table you reference is for cantilevered systems - i thought you were going for infill glass?? Get someone who understands this to review/design/specify for you.

fatty pang

Apologies, I had assumed a pane size of 2200 x 1200mm based on your picture which I forgot to mention.
The minimum imposed load is constant but the strength (thickness) of glass required will vary with both the size of the glass panel and the method of fixing. The ‘quick guide’ you have linked to, is just that as it makes no reference to the size of glass panel covered and the location of the fixing relative to where the line load will be applied. They are being conservative with 12mm toughened glass for a free standing barrier in a dwelling. 6mm would be adequate in many situations.

893bet

Johnnyhpipe wrote: »

Load per m doesn't depend on panel size as its specified in kN/m and kN/m sq. The table you reference is for cantilevered systems - i thought you were going for infill glass?? Get someone who understands this to review/design/specify for you.

I am! I had missed that!

Are you able to do the required calculations? Not asking for you to sign off on anything just guidance for a fee.

Johnnyhpipe

893bet wrote: »

I am! I had missed that!

Are you able to do the required calculations? Not asking for you to sign off on anything just guidance for a fee.

Not something I would take on. There might be others on here who would however.

Johnnyhpipe

fatty pang wrote: »

Apologies, I had assumed a pane size of 2200 x 1200mm based on your picture which I forgot to mention.
The minimum imposed load is constant but the strength (thickness) of glass required will vary with both the size of the glass panel and the method of fixing. The ‘quick guide’ you have linked to, is just that as it makes no reference to the size of glass panel covered and the location of the fixing relative to where the line load will be applied. They are being conservative with 12mm toughened glass for a free standing barrier in a dwelling. 6mm would be adequate in many situations.

6mm cantilevered?? No chance. Factored tensile stress would be approx 99N/mm sq based on a very quick calc. Toughened lam glass would take something in the order of 59N/mm sq. 12mm sounds spot on for a domestic cantilever balustrade so I don't believe the table is conservative. 6mm would be reasonable for infill - certainly not cantilever. Anyway - I digress!

BryanF

893bet wrote: »

I am! I had missed that!

Are you able to do the required calculations? Not asking for you to sign off on anything just guidance for a fee.

This board is intended for discussion of Construction & Planning issues, by fellow users, and as a place to openly exchange tips and advice for FREE i.e. no one must seek to gain personally, professionally or financially from their participation in the forum . It is NOT a consultancy service and it is strongly advised that you always appoint your own professional advisor(s). Be aware that being an open public forum you may not always get exactly the response you would hope for.

Structural items . Issues relating to the specification of structural components is prohibited. Any queries in this regard need to be dealt with by an architect/engineer privately.

Do not reply to a mod instruction on thread, use the PM function.

http://www.boards.ie/vbulletin/showthread.php?t=2055036302

893bet, you have recieved adequate structural advice & professional advice, take this off-line

893bet

Johnnyhpipe wrote: »

Not something I would take on. There might be others on here who would however.

That's fair enough johnny. Thanks for your assistance in any case. Lots to think about.