glass roof

[charlie-ia]

we dream of lying in a cosy bed, looking up at the stars through a glass roof (not just a skylight) has anyone any suggestions (cheap & practical)

how do you keep them crystal clear? any safety issues?

i saw that one on grand designs that could support a mans weight, but prehaps thats a bit fancy.

what do you lot wish for? anyone made their dream a reality?

 

[Penners]

what do you lot wish for?

The money to get a builder to finish this place.

(But he'll need to be the world's most patient builder, because his client will never stop saying, "Well, I wouldn't have done it like that...")

 

[shelli]

Hey charlie - Yes Monty thingy in London with his flared garage made of steel - that was something else - he was a clever guy

Pilkington self cleaning glass is the stuff they use on conservatories.

Maybe you could just go camping !! The problems we all seem to have with planning (see Graham's post about his greenhouse) makes you think it would be better to keep those dreams just that, safely in realm of own head!!

LOL shelli X [/quote]

 

[charlie-ia]

safely in realm of own head!!

thats really NOT a safe place

we have outbuildings, thought we might get away with it on one of those as it already has a patch of corrugated carport style plastic.

 

[Penners]

There are building regs about the construction of your house, but none that tell you where you've got to sleep!

 

[NT]

Roof glass would need to be wired, laminated or toughened. Wired is the cheaper. It would need to handle wind and snow loading. It would need to be double or triple glazed to avoid excessive cold, though I presume inner glazing could be little more than mylar film.

You'd want some way to address summer solar gain, such as whitewash or a white shade.


NT

 

[Flyfisher]

i saw that one on grand designs that could support a mans weight, but prehaps thats a bit fancy.

I would consider that to be an essential prerequisite, not fanciful at all. Anyway, it shouldn't be too difficult, glass is very strong. I've seen (and walked on) glass floors, so a flat glass roof shouldn't be impossible. Might be quite expensive though . . .

 

[Penners]

Roof glass would need to be wired

Why is Georgian Wired glass so called? It's never looked very Georgian to me.

 

[skier-hughes]

safely in realm of own head!!

thats really NOT a safe place

we have outbuildings, thought we might get away with it on one of those as it already has a patch of corrugated carport style plastic.

I'd just replace roof with all corrugated plastic and tell nobody.

Then I'd replace it with some form of firmer cover for the winter months..


Graham

 

[AMc]

You may have fun and games with meeting building regulations.
Part of our plan is to bring an 8m x 4m vinery 'into the house' which means double glazing and low emissivity coating - even then the overal U value (speed of heat transfer) is around 1.8W/m2K vs. 0.3W/m2K for an insulated cavity wall.
To meet the overall targets we will have to superinsulate elsewhere and may have to put in renewable/carbon neutral heating to meet the overall target for the house.
Our vinery quotes came in at £30-50K for the glass alone, I don't think cheap, glass and roof come into the same sentance since April 2006.

A good sleeping bag in the garden would be a much cheaper option

 

[NT]

You may have fun and games with meeting building regulations.
Part of our plan is to bring an 8m x 4m vinery 'into the house' which means double glazing and low emissivity coating - even then the overal U value (speed of heat transfer) is around 1.8W/m2K vs. 0.3W/m2K for an insulated cavity wall.
To meet the overall targets we will have to superinsulate elsewhere and may have to put in renewable/carbon neutral heating to meet the overall target for the house.
Our vinery quotes came in at £30-50K for the glass alone, I don't think cheap, glass and roof come into the same sentance since April 2006.

A good sleeping bag in the garden would be a much cheaper option

Is triple glazing not cheaper?


NT

 

[Pford75]

Not wanting to hijack the thread, but this touches on a subject we are going to be dealing with in a few weeks time.

We have a 'lean-to' verandah outside our kitchen.....this is timber construction with open sides and did have a corrugated plastic roof (which with age had begun to 'mist').

We had to remove the roof to access our guttering via scaffold and I'm loathe to replace the horrid plastic roof.

One option is clear, flat, acrylic which has the advantage of lower cost. The other option is glazing.

So, my question - Since this is external (ie. not part of the house), the U-values etc. are irrelevant.....but what sort of glass do I need...does NT's comment re: toughened etc. still apply? I'm asking because our glasshouse obviously just has horticultural glass and I'd like to minimise the cost, but prefer glass to acrylic

 

[biffvernon]

So what's wrong with horticultural glass in this situation? Cheap and you're not planning to walk on it.

 

[Pford75]

That's what I'd like to do.....but ...

1. Are there any safety regs that prevent me using horti....it's a large roof (30ft x 15ft)

2. Is there anything I can do to help keep horti clean? Wld like to avoid the expense of self-cleaning glass

 

[NT]

Not wanting to hijack the thread, but this touches on a subject we are going to be dealing with in a few weeks time.

We have a 'lean-to' verandah outside our kitchen.....this is timber construction with open sides and did have a corrugated plastic roof (which with age had begun to 'mist').

We had to remove the roof to access our guttering via scaffold and I'm loathe to replace the horrid plastic roof.

One option is clear, flat, acrylic which has the advantage of lower cost. The other option is glazing.

So, my question - Since this is external (ie. not part of the house), the U-values etc. are irrelevant.....but what sort of glass do I need...does NT's comment re: toughened etc. still apply? I'm asking because our glasshouse obviously just has horticultural glass and I'd like to minimise the cost, but prefer glass to acrylic

I dont know what BR say on this one, but I do know from experience that hortic glass roofs have a gradual breakage rate. So if you go for the low cost hort option you will find hanging cut glass above you occasionally.

Still, greenhouses dont seem to be cutting peoples heads off, so maybe its not a real safety issue.

Factories always used wired glass on rooflights for safety.


NT

 

[NT]

That's what I'd like to do.....but ...

2. Is there anything I can do to help keep horti clean? Wld like to avoid the expense of self-cleaning glass

Self cleaning glass doesnt stay clean, it just has a limited degree of self cleaning effect.

Perhaps if the roof were shallow enough, and used very shallow metalwork above the glass, you could turn the hose on it then put a Roomba up there

Slightly more seriously, I dont think theres any way to keep things clean outdoors, just a case of planning how to clean it ahead of time. I guess a broom with a giant handle might do it.


NT

 

[AMc]

Is triple glazing not cheaper?

I assume you mean than changing the heating? Probably not esp. as we'll have to replace the existing 15 year old oil boiler to heat the extra space.

The Green Building Bible (Vol2) puts U values of glazing at 4.8, 2.8 and 2.1W/m2K for single, double and triple with 12mm gap. The 3rd pane doesn't have as much effect as you would want and will add 50% to the weight. No one has offered us triple glazing but we may need to look at it.

Both our vinery quotes have U values (1.6 and 1.7) better than buillding regs for glazing, the problem is approx U values for a properly insulated roof are 0.16W/m2K for roof and 0.35 for walls which gives you a heck of a shortfall to make up! We'd be losing 10x as much heat through the glass as we would through a well insulated tiled roof

Adding more than 100mm of insulation on each (solid) wall elsewhere will result in rooms too small to be practical - they're only 3.5m wide to start with.

It's a tricky one and no mistake - putting in a wood pellet boiler system may not be the 'best' solution for a variety of reasons, but it may be one of the only ways we can actually renovate the house as we'd like to. As I've said before it's not sensible to spend £30K to renovate the vinery as a greenhouse so I continue to look for options.

 

[NT]

Is triple glazing not cheaper?

I assume you mean than changing the heating?

I meant cheaper than fancy sealed argon filled dg units.

The Green Building Bible (Vol2) puts U values of glazing at 4.8, 2.8 and 2.1W/m2K for single, double and triple with 12mm gap. The 3rd pane doesn't have as much effect as you would want and will add 50% to the weight.

With TG the inner sheet can be mylar film, adding nothing to the weight.

It's a tricky one and no mistake - putting in a wood pellet boiler system may not be the 'best' solution for a variety of reasons, but it may be one of the only ways we can actually renovate the house as we'd like to. As I've said before it's not sensible to spend £30K to renovate the vinery as a greenhouse so I continue to look for options.

Maybe you could make the roof QG. Once you've paid for the expensive glass, frames & installation, extra sheets of long life film cost relatively little. Just be sure its a type that will give good long life, 20 yrs or more, and that the inner glass is practically removable to replace the film one day.

You may need to put such a non-standard construction up yourself, or hire someone rather than looking for a ready made unit supplier. Everything about this implies non-sealed glazing, and you could prevent condensation by piping a dehumidifier to the interglazing area so that when in time it begins to mist you run the dh one afternoon and its clear for the next month.

The roof is the one area where I expect you probably could afford to lose a few half-inches, and a non-standard thing like this would wipe most of that 47k expense out.

U values of QG? I dont know, but I know a man who does, if youre interested to find out more.


NT

 

[AMc]

I can see
DG= Double Dlazed
TG = Triple Glazed
QG = Quadruple Glazed
but I'm at a loss to understand the overall construction?

Are you suggesting a non-sealed double glazed roof with two layers of mylar film? How does that work, film on the inside of each pane = 4x glazing?

I'd be very interested in how thermally efficient this would be and obviously I would need to convince building control that this was effective.
If you can give a bit more info it will all help with the mix of stuff in my head.

 

[NT]

Yes, 4 glazing layers, with glass on the outside on both sides for robustness and cleanability. A non-sealed construction with the addition of a dehumidifier to the inter-pane spaces to permit occasional demisting when needed. Small Peltiers would be the neatest way to do this, rather than a bulky household refrigeration based dehumidifier.

To get assistance with figures and design, there is really only one place to go: news:alt.solar.thermal.


NT