I would like some advice, I am constructing a conservatory roof which will be from double glazed glass. The conservatory will be 4.4 Meters from the house wall so with a 3 deg pitch will mean beams of 4.5 Meters. i have found a few company's that supply self supporting bars up to 4.8 Meters in length but i am worried that these may need a center purlin due to the bar length and the weight of the glass. Has anyone done a roof up to 4.5 M long with no center support and if so can they recommend a good supplier for the beams.
I can get 4 meter long glass but not sure about 4.5. I was intending on doing it in two units 700 mm wide with center joint as it would be too difficult for me to get one unit on the roof. I am thinking I might put a center pier in and a steel purling to support timber beams. At present i have 4 x 4 red hardwood beams which i could join onto along the purlin
dont forget roof glazing should be safety glass so a central mullion is advisable due to weight and transport
Yes I will be using Pilkington K toughened glass. I have been researching the best way to join the units. Mullion or Muntin bar is one option but can leak. Not worried about the support if i go with timber beams as i will have a vertical noggin across the joint. But i do want a good water tight joint. I am hoping to call the glass company this week to see if they do a unit with longer top sheet to over lay the adjoining sheet (I have herd some people but jointing with mastic. Not sure how good this would be). As for the beams i have spoke to a builder who advised a steel purlin would be safer, So I will put a 5.5 M steel one side and a 3 M steel the other side to make the 8.5 M with a center pier. Might need to get a structural engineer to calculate the size of the steels, hoping to get away with 127 x 73 H steel
With only a 3 deg pitch a glass roof is going to get very dirty very quickly - thought how you are going to clean it? Also, I can't see how you are going to join two DG units together at such a shallow pitch without getting a water trap at the join, although I guess it may be possible with some sort of sealant joint. Also that's one heavy roof, especially if you end up with snow on it. Can you not increase the pitch? Interested to here the eventual solution because I have a garden room project with a shallow pitch, and had considered using laminated glass but at the moment polycarb is favourite. As its an "outside inside" room mine doesn't have to have any thermal properties though.
There is Pilkington Activ self-cleaning glass,but needs a minimum of 10 degrees from horizontal, but works best with least 30° from horizontal for a conservatory roof.
I could look at increasing the pitch will have a look this week at the max angle. Not sure if I will get to 10 deg let alone 30. As for the weight the glass worked out to about 90 kg a sheet. This would be a spread load and I am looking at H beam across the middle. Still got to do some calculations but hoping to do attached picture, the red beam will run from house wall to front conservatory, the two brown ones equal length will run from sides and join onto red beam and the side walls will have wither brick or still columns depending on the price, Plus the glazing wooden beams will spread the load
Good the with Pilkington Activ you have in various colours, bronze, blue, & a couple of other colours for sun protection.
Thanks Rusty this has given me some info and an idea of overlapping the units by stepping the glazing bars. i have also done some quick calculations and should be able to get a 10 deg angle, may even get more will survey this tomorrow
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