Has anyone ever built trellis with glass or plexi top? I want to build knee-braced trellis across front of house to cover entry but don’t want to lose light so would like transparent sheet material on top. What are my options? Would prefer something as near like glass as possible, not plastic. Is laminated glass or wire-reinforced glass a possibility?
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How big is the top? My preference would be tempered glass in appropriate thickness.
I haven't really figured out dimensions yet, something in scale with front of house, probably around 2-1/2ft x 12ft.
Was also considering something similar on back deck, more like 5ft x 12ft.
the 2 1/2 x 12 piece would be no problem in 1/4 or greater tempered glass. The larger one would probably need to be supported. Check with a glass supplier (glazing,glazier etc.) for their opinions. Remember to allow for expansion and contraction due to temperature changes.
Laminated glass will work. I'm working on a project now where we're doing a greenhouse roof with laminated glass. The panels are about 2 1/2' by 5', there are about 40 of them.
zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
I'm also thinking of something similar for our front entry.
What kind of weight are we speaking about for tempered glass?
Best way to fasten against winds. (we are on the PNW coast 1/2 mile from the beach) Winds in this area can be sustained for 35-40 mph with gusts reaching 60 to 70 mph in bursts.
Very little danger of flying debris as there are no large trees or structures within several hundred feet. Moderate climate with little or no snow and winter temps almost always above freezing. Summer temps usually 70*-75* max....a bad day at the beach is better than a good day anywhere else... :)
You absolutely want to use safety glass in that application - either tempered or laminated.
Wire glass is not a safety glazing and it has only about 40% of the impact strength of ordinary clear annealed glass. It is not a very safe material in any application and is being phased out in many areas....avoid it.
Glass weighs 155lbs/cubic foot...so a little math will give you the weight at whatever dimension and thickness you need. Tempering glass doesn't affect the weight at all. But, laminated glass is made with two lites plus the interlayer so it could be considerably heavier depending on the thickness of each indidual lite.
How are you planning to attach the glass to the trellis?
I haven't a design yet but was thinking of plowing a groove/dado the length of some 2X cedar, cypress or redwood stock and lining the groove with some felt. Mitreing the corners, and then some felt pads if intermediate supports would be needed. I thought this might allow for expansion/contraction....a bad day at the beach is better than a good day anywhere else... :)
I've got recycled (separated) sliding glass door panes over a walkway outside one of my shops. Found out that some doors have thinner glass, maybe 1/8", which I didn't use overhead. The 3/16" panes got an extra rafter down the middle, for a 17" span. Used EPDM weatherstripping and screwed aluminum bars on the edges.
Close to a decade later, none have broken, even with blown branches hitting them. On this mountaintop we have wind. And large trees.
OTOH, they're never clean. I don't hang out there during hail storms.PAHS Designer/Builder- Bury it!
Oberon...too bad about the wire-glass. I thought it would look kind of cool.
Oldbeachbum.....not sure about advantage of dado/groove in battens. Seems like it might just foster decay/moss at least where I live. One project I know of the glass sheets were fastened to structure with silicone sealant and screwed down with 1x3 battens. Sheets were spaced 1/4" or so apart for expansion. I don't know though how well it held up.
Zak...glazing tape sounds interesting. Can you recommend type/brand?
You could use laminated wire glass - of course the cost might be frightening! If the wire glass was mounted in a location where it was pretty much impossible for someone to impact it with body parts it probably would be okay to use - again with the knowledge that it isn't really very safe - but if it is out-of-reach.
Anyway, I am not sure that I would use a dado for mounting a large lite of glass - I would be concerned that any warp in the wood might cause a stress point and crack the glass. I would suggest that a rabbet with glazing stops might be a less stressful alternative.
Don't know about brand- we just get stacks of rolls from the glass shop. Ask for butyl glazing tape, a good glass shop should know what it is. It's not the small, narrow foamy tape- it's like a tape version of bituthane, about 1/4" thick, 5/8" wide.
It's very sticky, especially if the weather is warm. When you're setting the panes, wipe down the tape with soapy water first, then you'll have a minute or two to slide around the glass before the butyl sticks it down for good.zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"
Well, you'll definitely want to secure all the edges of the glass with battens screwed into the structure of the trellis (or entryway, or whatever you're putting glass over).
We're putting ours down onto butyl glazing tape, which holds very well itself. Then, 1x3 redwood battens over the joints. We're not going to deal with the wind you get though, I'd make sure to overbuild that- the surface area will add up fast.
Just guessing on the laminated glass weight, I'd say that a 56" by 29" pane weighs about 30 lbs. Awkward, though, moving the stuff around on a roof.zak
"When we build, let us think that we build forever. Let it not be for present delight nor for present use alone." --John Ruskin
"so it goes"