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    • CommentAuthornr8861
    • CommentTimeFeb 21st 2008

    This is all new to me.

    We are about to start the foundations on our new build timber frame and are looking at various window options. We were at the Self Build show at the weekend and saw aluclad windows and are quite interested in them.

    Does anyone have these windows in their home or have any information on whether they are any good and if the internal wood is stained, whether it has yellowed or discoloured?
      CommentAuthorKeith Hall
    • CommentTimeFeb 21st 2008
    The Green Building Store ( no relation) have just launched a new range of aluminum clad windows so they will be deep green. I'm not sure if they are exhibiting at Ecobuild though.

    Alu clad windows are really only classed (by me at least) 'eco' when combined with a high rise build though. On houses timber only would be a more eco choice.
    • CommentAuthorIan Ashton
    • CommentTimeFeb 22nd 2008
    Try the triple glazed discussion here for useful names.

    Ours are available painted in 190 RAL colours or the 1900 NCS S colours, as well as 10 UV stable woodstains.

    Alu clad is very dificult to quantify its eco credentials, but our alu clad windows achieve at best a B, on the BFRC scale, while the equivalent painted or stained, will achieve an A. The cost difference is a no brainer, as re-decoration costs for the first time are about equivalent to the alu cladding. So factor in access, painting contractor (if you go that way), paint, transport of paint etc etc. I think they start to stack up well at 10-15 years old.

    I will leave it at that, and follow the other discussions, to make your mind up.
    • CommentAuthorGBP-Keith
    • CommentTimeFeb 22nd 2008
    Who is Ours Ian?
    • CommentTimeFeb 25th 2008 edited
    I asked same question in http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=527&page=5#Item_20. As no answer, I'll say that Ian Ashton is Swedish Timber Products, importers (or subsidiary?) of SP Fonster windows, one of the front runners in my 3G survey.
    • CommentAuthorMr VELFAC
    • CommentTimeMar 28th 2008 edited
    VELFAC are able to offer the following u values:

    1.54w/m2 - 4-16-4 unit argon filled + 1Nr low e coat.
    1.48w/m2 - 4-16-4 unit argon filled + 2Nr low e coat.
    1.18w/m2 - 4-12-4-12-4 unit argon filled + 2Nr low e coat.
    0.99w/m2 - 4-16-4-12-4 unit krypton filled + 2Nr low e coat.

    VELFAC windows are tested for air permeability up to 600 pascals with a recorded air leakage rate of below 0.12 m3 /(h.m2) at 50 pascals. Approved document L1 allows a reasonable design air permeability rate of 10 m3 /(h.m2) at 50 pascals.

    You may wish to read a report that I recently downloaded from the internet, which was compiled by Napier University's (Edinburgh) School of Engineering. This report illustrates the life cycle of window materials and offers a comparative assessment of PVCu, aluminium, timber and aluminium clad timber windows. Incidentally, this report does not encompass the VELFAC window principle, which is a true composite window, i.e. timber internal/main frame and an extruded aluminium external sash.


    As you will see, the report focuses on the embodied energy, which is the amount of energy consumed during the manufacturing process. The report also assesses the durability of the frames and expected life cycle.

    In conclusion the report suggests and endorses that aluminium clad timber windows will provide an expected service life in excess of 40 years.

    Timber could not hope to achieve this, even with a regular maintenance regime. However, timber is a carbon neutral product and this is one of the main benefits for using it within an aluminium clad timber window construction.

    In the experience of many local authorities, PVCu will not achieve a lengthy life cycle. I personally think that the expected 25 year life cycle of a PVCu window, illustrated within the report is rather optimistic. In addition PVCu tends to get land filled, which allows the release of environmentally dangerous substances, thus contaminating adjacent land.

    Aluminium can be repeatedly recycled and with production facilities powered by environmentally friendly sources such as hydro-electricity schemes, the argument for aluminium becomes more credible.

    A lot is said with regard to the energy used to produce aluminium, however little is said with regard to the energy used to produce glass as it is assumed all glazed units have a similar lifespan.

    It seems acceptable to consider a sealed unit housed in a timber frame as having an expected life if between 10 and 15 years, whereas with a true composite window the glazing is housed in an aluminium sash. All VELFAC sealed units are factory installed, drained and sealed. It is my considered opinion (and VELFAC UK experience) that sealed units installed and drained correctly and housed in aluminium sashes can and do last 20+ years.
    • CommentAuthortomlin
    • CommentTimeMar 29th 2008
    I'm also looking at window options for a new build and really like the idea of alu clad or alu/wood combination.
    Perhaps you can answer questions ;
    How do you avoid condensation due to cold bridging on your products ? In my previous house we had all aluminium units made by Monarch and this was often a problem.
    In general, how do your prices compare with other products which are timber clad in aluminium (ones Im looking at are well known brand of Norwegian origin) ?
    • CommentAuthorCWatters
    • CommentTimeMar 29th 2008 edited
    There are a couple of companies that make BRONZE and Bronze clad wooden windows if they are of interest... No need for paint or coating like Aluminium.. Perhaps a tad expensive.

    http://www.fensterbau-wetzel.de/index_en.php (German quality, modern design, choice of woods, good U-Values)

    http://www.bronzecasements.com/ (Solid metal, traditional design, ideal for heritage/replacement)

    http://www.bronze-window.com/ (American, not sure if they export).
    • CommentAuthorCWatters
    • CommentTimeMar 29th 2008
    > How do you avoid condensation due to cold bridging on your products

    I'm not Mr Velfac but it is possible to avoild this. You can get windows that are aluminium on the outside and wood on the inside. You can also get wondows that are aluminium inside and out but with the two parst seperated by a thermal barrier.
    • CommentAuthorMr VELFAC
    • CommentTimeMar 29th 2008 edited

    At no point on the window does the aluminium form an internal surface.

    VELFAC windows are thermally proven (see u-values above which are whole window values).

    Prices are competitive, thus VELFAC supply more composite windows in UK than any other.
    • CommentAuthortomlin
    • CommentTimeMar 31st 2008
    As part of a wider proposal, I have a quote for 19 windows, two external doors and a sliding patio door. Its based on what I think is probably mid-range PVC which is our very last choice (like when hell freezes over) and comes in at around £7K. Might be a tall order but can anybody give me an idea of how this price would compare with a timber product of say, Nordan quality, both alu clad and non alu-clad ?
    • CommentAuthorbiffvernon
    • CommentTimeMar 31st 2008
    It's not just the up-front price that counts. Try dividing the price by the number of years you expect the product to last.
    • CommentAuthorMr VELFAC
    • CommentTimeMar 31st 2008

    Forward your requirements to VELFAC Direct, Kettering. They will provide costing without fuss. I would guess add at least 50% on cost though.

    • CommentAuthoralec1702
    • CommentTimeJun 2nd 2008
    Don't do it!

    Alu clad painted windows are only low maintenance if they are properly wrapped in the factory before shipping. We've had two sets of cladding and a "magic man" and ours still don't look great after only 4 months. To be fair, the manufacturers offered us a third set of cladding, but its not the best green option.

    If I could do it again, I'd order timber 3G units and have them stained in a linseed based paint like Holkhams or equivalent.
    • CommentAuthordocmartin
    • CommentTimeJun 15th 2008
    Looked for a reply again, today: had to hastily edit my last post which seemed to be anti- timber windows. That was not what I intended; Aluclad is my favoured option. As I have no experience of Aluclad I am keen to hear about potential problems/snags.
    • CommentAuthorAli 1
    • CommentTimeOct 30th 2008
    There are not many downsides to alu-clad really, virtually maintenance free, only thing I can think of is if the surface got chipped the touch-up might show - like it would on the surface of your car. But hey theyre a great protective surface to the timber window underneath.
    • CommentAuthordocmartin
    • CommentTimeOct 30th 2008
    Ali 1, do you actually have Aluclad windows? Perhaps experience of fitting them for clients?
    Frustrating that I never got a reply from Alec1702;the sort of (bad) experience that he apparently suffered would be valuable information for us all.
    • CommentAuthorGowzer
    • CommentTimeOct 30th 2008
    docmartin, I am reading your comments, and I do have aluminium cladded windows and they were so easy to fit as we got fitting instructions from the supplier we used. They came very well packed from the factory and we never had any problems with the surfaces being chipped as Alec1702 has had
    • CommentAuthorAli 1
    • CommentTimeOct 30th 2008
    docmartin - yes I do work for a company who supply and install them and am interested to read everyones views on the subject as alu-clad seems to be getting ever more popular, even though its been on the go for quite some time. Also I am learning as its a new job and taking information from everywhere I can find at the minute lol :bigsmile:
    • CommentAuthorfayevans
    • CommentTimeJun 7th 2009
    Hello all,

    I am trying to find a company who will do alu-clad or alu-wood type windows( PALE GREEN EXTERNAL WITH OAK INTERNAL) for a barn conversion we are currently working on, i am finding it very hard to find any company that trades in the shropshire/worcester area, if anyone has any contacts or can recommend a company that trades in this area can you please let me know?? we are having to supply our local council with a sample of what we want, thats even before we can place an order for them to even approve the type of windows we want, they seem to have been about for some time now but with very little information, please can anyone help with our problem!! thanks for reading,

    • CommentTimeFeb 26th 2010
    Tip from Peter Starck on http://www.aecb.net/forum/index.php?topic=2336.0 :

    "I am using Al clad timber windows from AM Profiles in my build. This is a UK company that manufactures PassivHaus certified Hermann Gutmann windows under licence. I found their quote to be about half that of Internorm." http://www.amprofiles.com/pages/news/0904.html
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