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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthornbishara
    • CommentTimeJul 24th 2019
    Hi all,

    I’ve got A rather dark corridor in my extension design and I suggest to the architect that we put a sun tube or similar in it to provide natural daylight. I things have worked out, we can just go for a vaulted ceiling over that section as I am doing in the bedroom beyond and I quite like that idea because it will make a small space feel more spacious.

    To my surprise, he doesn’t like some chips – not because of the U-value, but because he doesn’t think they provide much daylight. My only direct experience is my parents bungalow where I imagine it is rigid and probably not particularly long, but it does seem to work pretty well. The reason that I thought of them was both because it works for them and because I had an idea that it was better insulated – perhaps depending on the company and model that you buy?

    Anyway, one advantage that I thought of of of the locks at this point in the house is that in hot weather we can open it and it will really help natural ventilation – chimney effects et cetera as it will be at the highest point of the house near the top of the stairs. Architect agreed with this ( not sure why he didn’t think of it but anyway), but the flip side I thought about heat loss in the velux and wasn’t sure how bad that would be / whether I could mitigate that in any way (I saw the retrofit installation thread elsewhere on this one), any thoughts anyone else has about solar tubes versus velux and preferable versions of both?

    Thanks very much,

    • CommentAuthorowlman
    • CommentTimeJul 24th 2019
    I'm not sure about the comparative benefits of roof lights versus sun tubes but I'd wager that the roof light is better plus as you say it may help with ventilation.
    Heat losses aside, the other practical difficulty with relatively high up, inaccessible, roof lights, ( you mentioned top of stairs, ) is the cleaning aspect both inside and out. This isn't so bad if they are in a more conventional application and you can rotate them, but if you need a scaffold to do a bit of window cleaning it isn't much fun. It's something to bear in mind.
    • CommentAuthortony
    • CommentTimeJul 24th 2019
    No way should you use a solar tube, always use a Velux in a lightwell
    I was intrigued to see that the architect 'doesn't like some chips'. I assume some chips = sun tubes. If not, I'd agree with him that they don't provide much daylight. :bigsmile: Sorry! Nick

    P.S. I would go for Velux in a well-insulated light-well or, if as you say, you are having a vaulted ceiling, not in a light-well at all. I am always somewhat dissatisfied with the quality of reveal insulation achievable (or not) with roof-lights such as Velux, and the need to double-up rafters and thus increase thermal bridging irritates me too.
    • CommentTimeJul 24th 2019 edited
    Posted By: tonyNo way should you use a solar tube, always use a Velux in a lightwell

    Could you elaborate on your reasoning.
    • CommentAuthortony
    • CommentTimeJul 24th 2019
    Not enough light, too much condensation problems, plastic dome, draughty, naff flashings, naff

    Velux, dg or 3g, I only use single rafters, set back to allow insulation, good flashings, time served, repairable
    Tony, my local BC would not agree to single rafter only - mine was on retrofits with c75 x 50 rafters, and they insisted on doubling up.
    • CommentAuthortony
    • CommentTimeJul 24th 2019
    Mine do too but it isn’t always necessary,
    I didn't use Velux because at the time they didn't supply 3g without trickle vents so used Fakro PH window. It was eight years ago and Velux may have caught up now.
    • CommentTimeJul 25th 2019
    I don't think either offer a perfect solution.

    I am not a big fan of Rooflights at all, especially on a south facing elevation, due to overheating.
    Also there are issues with thermal bridges and cleaning them if they in a high ceiling.

    I agree suntubes are poorly made although they do provide plenty of light if they are sized correctly, and the tubes not too long.
    I have only used them on flat roofs where they have integrated rubber flashings.
    Its a shame they don't make one with better airtightness and double skin dome.
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