Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



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.

Buy individually or both books together. Delivery is free!


powered by Surfing Waves




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




    • CommentAuthorMarkyP
    • CommentTimeAug 18th 2016 edited
     
    we have a large roof light specified in the flat roof over the new kitchen (1200 x 2500). I'm looking at a 3G flat roof light from roof maker: https://roof-maker.co.uk/fixed-flat-rooflight/

    it looks like a quality product, and is 3G with an insulated upstand frame. The glass u-value is stated as 0.6 W/m2K in the blurb but rummaging further the EU cert of conformity states a whole product u-value of 0.6.

    Does anyone have any experience with this product or can suggest others I could consider? rest of the house will be quality 3g painted timber windows, looking for a quality roof light with a similar thermal performance to the windows (whcth are a shade under 0.8)

    not sure of forum policy here, whispers welcome if people prefer not to offer opinion on specific products publically. thanks
  1.  
    make one, I did from instructions on here and I'm no expert. I used DG but sure you could make your own using 3G
    • CommentAuthorMarkyP
    • CommentTimeAug 18th 2016
     
    yeah, it's an idea. My issue at the moment is time. Trying to juggle the project and my job and I've already got a lot of big DIY elements in the plan. The flat roof window is one aspect where the thought of screwing it down and job done is very appealing.
    • CommentAuthorMarkyP
    • CommentTimeAug 18th 2016
     
    but having said that, I suppose it's just a couple of insulated upstands and piece of 3g dropped on top. Hmmm.

    It will be visible from above, the manufactured ones seem to have an obscured perimeter section of about 75mm, I assume this hides the upstand and bonding. I wonder if I get glass like that made up. the manufactured units are not cheap, that's for sure so I could make a decent saving DIY here.
    •  
      CommentAuthordjh
    • CommentTimeAug 18th 2016
     
    Posted By: MarkyPit looks like a quality product, and is 3G with an insulated upstand frame. The glass u-value is stated as 0.6 W/m2K in the blurb but rummaging further the EU cert of conformity states a whole product u-value of 0.6.

    I agree it looks good but I'd be careful to double check that U-value. I don't understand all the standards etc but it seems odd that three different methods give exactly the same value, especially when one is labelled Ug and another whole product. I'd ask to see the original TRADA certificate/report for sure. I can't see how 20 mm of XPS in the upstand gives a frame U-value of 0.6, nor for that matter how the glazing gets to 0,6 without more detail. And make sure the U-value is calculated as a horizontal rooflight, not as a vertical window.
    • CommentAuthortony
    • CommentTimeAug 18th 2016
     
    Build your own well insulated kerbs, top edge laid to fall 1:40, sit a 3g stepped unit on top on foam with Ali trims on three sides. We fixed with copper brackets and poly sulphide mastic.
  2.  
    Posted By: tonysit a 3g stepped unit on top on foam with Ali trims on three sides.

    By a stepped unit do you mean the top glass extended to over hang the lower edge to avoid the need for trim on the lower edge and thus avoid puddling.
    • CommentAuthortony
    • CommentTimeAug 19th 2016
     
    Yes, and to protect the spacers.
    • CommentAuthorMarkyP
    • CommentTimeAug 19th 2016
     
    Posted By: tonyBuild your own well insulated kerbs, top edge laid to fall 1:40, sit a 3g stepped unit on top on foam with Ali trims on three sides. We fixed with copper brackets and poly sulphide mastic.


    was the window visible from above? I'm thinking about how I'd avoid the top of the upstand and mastic from being visible. The fancy manufactured units seem to use a band of obscured glass, not sure that would be possible to order. Perhaps I could use a band of dark colour glazing film on the underside of the glass, and then bond to the upstand.

    Do you have any pictures or design drawings? I'd be interested to see any detail if you have it.
    • CommentAuthortony
    • CommentTimeAug 19th 2016
     
    The ali trims that we used were wide enough to cover seeing the mastic and they were visible from above, we built them bespoke without plans.
    • CommentAuthormarsaday
    • CommentTimeJun 25th 2018 edited
     
    I would like to bring this thread up again to discuss these units made by panoroof.

    What do you all think to them. Really they are just triple glazed glass units siliconed onto a supplied 70x70mm upstand.

    The difference between this unit and other suppliers is the missing aluminium frame. These frames also screw into the upstand.

    I can get these glazed units made much cheaper from a local glass supplier. Probably half the cost.

    The only bit of extra work i would need to do is make my own rebated upstand.

    https://www.panoroof.co.uk/product/1000mm-x-2500mm-triple-glazed-clear-skylight/

    Tony mentioned earlier about making your own kerbs. How exactly would you make these kerbs ?
    • CommentAuthortony
    • CommentTimeJun 25th 2018
     
    I have recently seen several vaguely similar rooflights with puddles on them, you can see the puddles even when they are not there by the dirt left behind and the outline. One did have a fall on it but the glass sagged under its own weight.
    •  
      CommentAuthordjh
    • CommentTimeJun 25th 2018
     
    Posted By: marsadayWhat do you all think to them.

    I wouldn't buy anything from them, myself. It looks like a shoestring operation, and they leave you to do the falls and all the fixings.
    • CommentAuthormarsaday
    • CommentTimeJun 25th 2018
     
    It seems all the companies leave you to do the falls and fixings.

    So no one thinks i could just make my own roof windows then ?

    My window size will only be 1000 x 1000mm, so i don't think i will get sagging issues with this smaller size.

    I need to speak to the glass maker to see if they can include all the dark masking tape which hides the silicone etc.

    I did speak to them before and they can do double glazed units with a further single pane bonded on the top which also overhangs the edges.
    • CommentAuthortony
    • CommentTimeJun 25th 2018
     
    I always have my own rooflights for plat roofs made up, 3g stepped top pane overhangs 50mm Ali angles mask the other sides

    Always set to fall of min 1:40
    • CommentAuthormarsaday
    • CommentTimeJun 25th 2018
     
    I have been reading another thread about the panoroof windows and many people seem happy with them.

    I have also worked out what i would need to order to make my own window unit.

    The key is to get the pacified edge in place from the manufacturer. This will give you that black out line which you need to hide the plaster board finish plus all the silicone.

    So it sounds pretty easy to have these made up at a fraction of the price of a typical roof light.

    My roof fall is 10 degrees so i should be able to set these units inline with the roof line.

    I will report back when i get some more info from my glass supplier. DG units cost me £28 plus VAT. So i will need the extra outer pane and all the panes will need to be toughened. I wonder if a unit might cost me £100 plus VAT for 1sqm ?

    This thread gives you some good info on how these windows go in:
    https://www.diynot.com/diy/threads/panoroof-skylights-are-they-any-good.464262/
    • CommentAuthormarsaday
    • CommentTimeJul 3rd 2018
     
    Right i have my prices for 1000 x 1000mm triple glazed units. They are £205 inc vat, collect only.

    So getting these made up is pretty easy. However i have spoken to BC and he is asking about the perimeter of the boxing for these units. What insulation will go in them ?

    I can add insulated plasterB around these edges i suppose, but the maximum i would like to come out (on top of the 12.5mm plaster board) is 25mm. Is there an insulation which is thinner, but better at insulating compared to the standard kingpins etc? I may call up kingpin to get some info.

    This is a drawing of my upstand which i sit my glass on. This is taken from panoroof and they don't have any insulation in there.
    • CommentAuthortony
    • CommentTimeJul 3rd 2018
     
    Should be same as roof you could use aerogel
    • CommentAuthormarsaday
    • CommentTimeJul 3rd 2018
     
    I am using 150mm kingspan in my roof. These windows raise above the roof however and so the perimeter needs insulating. The BC guy said these are like the walls and so need the 50mm required.

    I couldn't get through to kingspan technical today. Tomorrow hopefully. I am sure there is a product which is thinner, better insulated but very pricey. Luckily i don't need a lot of it.
    • CommentAuthormarsaday
    • CommentTimeJul 3rd 2018
     
    The aerogel website looks good, but i need to speak to them about u values and cost.

    Does anyone know how thick the aerogel needs to be with their magnesium board to meet a u value of 0.28 ?
    •  
      CommentAuthordjh
    • CommentTimeJul 3rd 2018
     
    Ideally the upstand should be better than the roof since it increases the heat loss area and can also compensate for the poorer performance of the rooflight to a small extent.
    • CommentAuthormarsaday
    • CommentTimeJul 3rd 2018
     
    Yes, but does anyone know how to achieve this ? The aerogel looks a good bet, but i need to speak to them tomorrow to get some info.
    •  
      CommentAuthordjh
    • CommentTimeJul 4th 2018
     
    Everyone knows how to achieve this, but it's already been said - aerogel.
    • CommentAuthormarsaday
    • CommentTimeJul 4th 2018
     
    Speaking to the aerogel suppliers it seems this area of the roof is a junction and so should be treated as a window reveal would be treated.

    This means i can use the 10mm blanket and screw plasterboard over this. The section of the window which is going to be uninsulated is about 100mm in height.

    I will have 16 x 1m lengths is clad and these will be about 360mm in depth. So i need to cover just under 6sqm of area.

    The cost is £120 per 1.2 x 2.4m blanket area and i will need two of them.

    I need to speak to BC to see if this is all ok.

    Do you think this is best placed on the outside of the upstand or internally behind the plaster board ?
    •  
      CommentAuthordjh
    • CommentTimeJul 4th 2018
     
    Posted By: marsadayDo you think this is best placed on the outside of the upstand or internally behind the plaster board ?

    It should be continuous with the roof insulation.
    • CommentAuthortony
    • CommentTimeJul 4th 2018
     
    +1
  3.  
    A *very rough* calc makes that about 0.8W/m2K at best - ish.
    • CommentAuthormarsaday
    • CommentTimeAug 2nd 2018 edited
     
    Update:

    BC have ok'ed 25mm insulated PB around the internal perimeter of these windows.

    My units are going to weight 35kg each at 1sqm of triple glazed glass.

    I have a question regarding the final way of finishing off these roof windows.

    Do you think the following construction will be ok around the perimeter area of the windows.

    My roof build up is as follows:

    Doubled up 125 x 44mm joist.

    Over this will be a sheet of OSB3 18mm.

    Over this will be 100mm kingspan insulation

    Over this will be osb3 18mm again.

    The final finish will be a tata steel metal roof.

    The 150mm upstand will then sit and screw down into the final layer of OSB3 and the glass unit will sit in this upstand.

    Do you think this construction is ok or would i need to create a perimeter of solid wood all the way up to the start of the upstand ?

    Its just i have seen a few examples of these roof lights in construction and around the perimeter they have a solid frame all the way around.

    My preferred way would be better from an insulation point of view, but just concerned it will be strong enough. I think it will be but just wanted other opinion.
    •  
      CommentAuthordjh
    • CommentTimeAug 2nd 2018
     
    I don't understand your description. What is the glass sitting on? What is 'The 15mm updated'?

    Note that the pitch of your roof is right on the limit of the Colorcoat and that Tata show ventilation under the top layer of OSB and a breather over the top of it.

    Purely for interest, I'm curious why you've chosen the steel roof rather than say EPDM?
    • CommentAuthormarsaday
    • CommentTimeAug 2nd 2018
     
    That should be 150mm upstand.

    So the glass sits on this.

    My roof pitch is 10 degrees, well within the roof limits.

    My roof is warm and so osb3 with a membrane over this for added security, but prob not really needed.

    Epdm roofs are very ugly. I would do a fibre glass one over that. The steel roof is a lower cost alt to the zinc roof which looks great.

    Do you understand my question about the strength around the perimeter of my roof window ? I think it will be strong, but wanted to check here.
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press