| Archive for Downsizer For an ethical approach to consumption |
| tahir |
Windows/glazing for self-build
Well I've just got back from looking at some glazing, tomorrow we're meeting architect, env engineer and structural engineer so we can get the last bits of speccing done, the aim is to be able to send tender docs out by 1st wk Feb. What kind of glazing will you go for? We're looking at aluminium clad timber. |
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| Behemoth |
Is that the composite stuff? Aluminium profile on the outside, timber on the inside? Which suppplier/manufacturer? | ||||
| tahir |
Yeah, timber inside, foam in the middle, al on the outside, we're looking at: the normal (no blinds) version of this one http://www.internorm.co.uk/cps/rde/xchg/internorm_en/?rdeLocaleAttr=en and this one http://www.albo.co.uk/aluminium-windows-al-trend-passive.htm |
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| Behemoth |
How does it compare in price to timber windows?
Veg Plot - double congrats. 
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| tahir |
A bit more (never really checked) but no maintenance is highly attractive | ||||
| Behemoth |
I'm tempted for my dorma window. | ||||
| vegplot |
We're undecided at the moment. We want to be a green as we can but we'll have to be realistic with what's acheiveable. |
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| tahir |
They make sense for us because the whole house is going to be very airtight, not sure how much benefit you'd get from the ones with the foam insert in a normal house, prolly best going for the cheaper option: http://www.albo.co.uk/aluminium-windows-al-trend.htm |
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| Behemoth |
Thanks - there's a couple of local suppliers who I'll investigate. | ||||
| RichardW |
Those composite windows have SIX bits of timber stuck together to make up the frame. I wonder if thats why the warranty on the wood is half that on the Ali.
Would you not be better off with thicker solid wood frames? I know the calculated thermal values are not as good but its also been assessed that the calcs dont match the real world performance of solid timber. Must have lots of embodied energy in making those windows. Richard |
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| tahir |
Undoubtedly but you're not going to have to repaint/lacquer the frames every x years. |
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| vegplot |
Solid wood windows have their appeal. As we're going to whitewash external walls every 2-3 years then oiling the windows at the same time wouldn't add too much to the burden. |
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| tahir |
I've been advised not, plus as I say there's a lot of appeal in not having to repaint. Most of the rest of the build (apart from the slab) will be quite low energy. |
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| tahir |
But you're much more DIY than me, I generally don't have any free time for maintenance etc, all that I do have is spent on growing things. I'd love it to change but I can't see it happening, once we get the house built next project is to leave work and start up a farmshop or suchlike. |
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| resistance is fertile |
Timber, like alot of natural insulation, works dynamically, with warm and cold air travelling (albeit very slowly) through the wood in both directions, warm air affecting the ingress of cold and vice versa. This is why thermal calculations come up short on dynamic insulation, resistance varies and can be dramatically enhanced in a larger section solid timber joinery unit. Alot of assessment started and finished at 'potential cold bridge' and didnt look any deeper. We use a saturation finish of organic nut and fruit oil at manufacture coupled with occassional (every few years) application of the same oil, no need for too miuch prep and no fragile finish relying on its surface integrity to keep the weather out. Aluminium windows are estimated to use 30-100 times more primary energy input than a timber window and another problem of the composite type (other than the foam itself) is the danger in condensation within the frame itself due to the differential thermal performance of the constituent parts, especially as several lower grade individual timber elements are often used in the construction. Annual cost, accounting for all investment and maintainance, favours timber units with a life expectancy of 30 years or more. Whilst purely aluminium windows can be recycled, and timber reused, recycled or used as fuel, composite windows cannot due to the bonding agents used in their construction. |
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| tahir |
In the gluelam? |
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| resistance is fertile |
generally yeah, and in the way claddings are applied in some systems. | ||||
| tahir |
The Internorm system has 3 gaskets to deal with the dangers of condensation, no idea how much less aluminium is used in a clad system as opposed to a fully aluminium one, or how the embodied energy/recyclability stack up against say fibreglass (David Oliviers favourite), or UPVC (offered by many that do Passivhaus stuff).
To be honest though the biggest turnoff for us is that none of the wood windows we've looked at look like real wood, and we haven't had anyone that can show us something that is real, solid timber, in the flesh, or even pictures and tech spec of. Seeing as the bulk of the house is going to be clad in oak shingles a wood glazing system would obviously sit best with it. |
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| vegplot |
I'm told oak isn't ideal for window frames. It is used but is prone to movement as it stabilises especially in early years, the movement tends to be small but can cause sticking windows.
I'm relaying this from someone who works making oak furniture rather than from direct experience. If it's impregnated with oil during manufacture and maintained then I suspect the problem would be minimised. |
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| resistance is fertile |
I think the biggest single problem with the composite systems on a practical level (putting aside the energy/environmental stuff) is that Im totally unconvinced they are a long term product. Even looking at it on a 'weakest link' level a product made up of a complex arrangement of small sections and low grade material will just not stand the test of time.
This has a large knock on re sustainability, in the same way that many sealed double and triple glazed units have. Its great how efficient they are when new, but if they have a lifespan of around ten years before they effectively breakdown and need replacing where is the saving or energy efficiency? Most large scale manufacturers just dont do nice, solid wooden windows as they are supplying a mass market and are not craftsmen joiners, able to respond to individual needs with a quality product that will last. Unfortunately such firms products are often 'specified' rather than joinery being 'designed' as part of the whole. The result is sadly often to the cost of the quality of the finished product and the local/smaller skilled makers. |
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| tahir |
Actually, just remembered a solid wood one that looks OK, finger jointed coppiced chestnut from a firm in E Sussex, loads of dosh and (really) poor U values.
We're not averse to any species of timber as long as it looks real, all of the other timber elements in the house will be very real and solid. In fact I think that was kind of like gluelam in it's makeup |
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| tahir |
True, but a punter still needs to know exactly what they'll be getting from a craftsman joiner, particularly in terms of performance and longevity (which is I'm told as much down to detail as materials) |
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| vegplot |
I know of a window maker whose work is very good but I've not yet had a chance to really take a good look at it. He's in it for the love of wood rather than performance.
I've got his details at home. |
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| resistance is fertile |
Oak is prone to movement and shaking. But if the correct timber is selected, properly dried for its intended use and the building and treating is done with care and attention a good oak window will outlast us all! We use chestnut alot for its stability in the weather. |
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| tahir |
Which kind of defeats the point of using someone like that in an airtight construction. |
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| gil |
I just split this section out from the main thread, as it's a topic in its own right. | ||||
| tahir |
We seem to have lost resistanceisfertile's last post 
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| resistance is fertile |
That is so true, I have seen lovely windows show up from firms and its the drip detail or closing detail that lets them down so that within a few wet weeks they are malfunctioning or suffering from water damage, what a waste of timber and time (let alone money!) Most of this though is down to that elusive middle ground between architect and joiner, one 'specifies' and the other 'makes'. Details get missed in between if the architect doent know enough about joinery and the joiner is concentrating on building exactly what he has been asked to. Perfect windows and doors are acheived when the joiner is given proper shop drawings that give all tolerances, construction detail and weather/draught proofing detail. As long as thats sorted, you cant beat a one off set of chunky timber windows that make a property truly individual. |
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| resistance is fertile |
I got lost in the ether as I was writing the thread got split and my quotes got stuck 
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| gil |
But I saw it a minute ago in the main self-Build thread 
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| tahir |
I spoke to Jon about this and he was quite disturbed at the prospect of having to specify design details for glazing, in his view glazing is such a specialist science, especially when you're talking about PassivHaus(ish) standards that you'd need a specialist to spec them. |
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| tahir |
S'OK he's reposted. |
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| resistance is fertile |
Thats the (perfectly understandable) gap Im talking about and why we specialise in those details as well as the overall schemes. We supply such info to many other practices. |
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| tahir |
I must have misunderstood what you said to me then. |
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| tahir |
I'll email you his details. |
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| resistance is fertile |
Its a tricky one for alot of architects to go into, but rather than go over to mass produced stuff we often consult and design joinery for practices that want to fit bespoke joinery but need a hand on the detail. | ||||
| vegplot |
I should have qualified that. I'm not saying he doesn't have performance as a priority I'm not as familiar with his work as I should be. His windows may outlive us all. Edit: Are you planning on install heat recovery? |
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| vegplot |
I looks like I may be needing your services on some detail before long 
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| RichardW |
I dont think I would buy a product where the outside has a longer expected life than the inside especialy when the inside cant be replaced on its own. Why else would they give one a 10 year warranty & the other a 5? To my mind the 10 years is worthless if the other half will need replacing in less time. All wood ones can be repaired easily by any skilled wood worker.
Richard |
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| resistance is fertile |
Completely agree, Comes back to the weakest link again! | ||||
| tahir |
http://forum.downsizer.net/viewtopic.php?t=38774&start=0&postdays=0&postorder=asc&highlight= |
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| carolyn |
My OH has his own bespoke joinery company with 'proper windows' based in Mid Wales - just pm me if you need any info from him. | ||||
| Behemoth |
Having dug deeper in the poor spelling and grammar (the 5 year guarentee is for the 'hole' unit'), the 5 year guarentee is actually covers the painting, glazing and handles/locks. i.e. the bits subject to customer abuse. |
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| vegplot |
I can see why air tightness is important. |
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| Lorrainelovesplants |
We are building a small exdtension to an agric shed which will serve as an office/workroom. The UPVC double glazed window we have got and UPVC door were given on freecycle. They are perfectly sound, and we can jig the building and openings to suit the build. | ||||
| cassy |
We're going for timber windows for the above reason plus the lower embodied energy and end of life re-use. I'm looking at sash windows as a way to provide good air quality even in bad weather with internal shutters and/or secondary glazing in the winter. I would prefer a local hardwood (failing that FSC hardwood from as near as possible, not New Zealand as I've seen advertised for some 'eco' windows  ) so that the main maintenance will be oiling.
Ideally I'll get them made by a local craftsman, but as we're at least 2 year off that point, I haven't got as far as finding someone yet! We're not aiming for an air-tight structure (only a non-leaky, non-cold spot structure) so the air-tightness of the windows is of secondary importance to their performance in removing moist air from the kitchen and bathroom. The quotes I've had seem to indicate that timber windows are more expensive than composites (for our spec) but as has been said, good timber should outlast me, so I'm willing to buy them one or two at a time! 
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| resistance is fertile |
Another point is that in going down the path you describe you will establish a relationship with a skilled firm or individual who can become a very valued asset around the place! |
