Hello All, Been following threads on here for a few months, getting back lots and lots of very useful information which has been helping with a building project here in North East London - a slightly eccentric Victorian era outhouse building which I am trying to convert into a cosy ecofriendly pad!

This first post is two things - a round-up of some quotes that I have received recently from various companies for 3G and 2G bifolding doors, and a general question about why on earth the prices I have been getting back are much higher than the £300 pm2 to £500 pm2 that people are generally suggesting for this kind of unit.

A quick description of the units - measuring 2400mm in width by 2300mm in height, with a single leaf opening to the right and acting as an "everyday door" and the other two doors "bifolding" to the right hand side. Here are the quotes that I have received so far (all exclusive of VAT and delivery) with U values where they have been given -

Howarth - 2G units 4/16/4 argon fill - £2204.83 (£399 p m2)

Ecoplus / Green Building Store - 3G units, 4/12/4/12/4 argon fill, U value 0.7 w/m2 - £5341.96 (£967.57 p m2)

Vrogum / Environomix - 2G softwood £3819.47 (£652.93 p m2)

Vrogum / Enviromix - 3G aluclad U Value centre pane 0.6 - £6523.84 (£1181.85 p m2) (note that these last 2 do include delivery)

Russell Timbertech - 2G (3G not available for bifolding doors) - £3668 (£664.49 p m2)

Ecomerchant - (supplying bifolding Viking Doors) 2G U-Value 1.41 w/m2 - £2457.50 (£445.19)

It runs contrary to the excellent advice of other users of the forum, but it seems like there is a big disparity still between 2G and 3G prices, with 3G availability still quite limited and prices running above £1000 p m2! I'm really not sure why these are coming back so pricey - perhaps because I am trying to incorporate an "everyday door" since this will be the main entrance to the house?

Any advice welcome - otherwise I guess I just have to get haggling!

Bifold for some reason is a) rare in 3G b) very variable in design/neatness c) ridiculously expensive. Sliders are cheaper and avail (by v special order) in 3G. Don't overlook the possibility of sliding one pane (on one track) or two panes( on 2 parallel tracks) away completely to a 'blank' position, leaving the opening completely open.

Hmm just checking the Viking brochure again it seems there might a bit of confusion about the "Tilt and Slide" door, not sure if one of the panes can act as a side swing opener as well as a slider - going to give them a ring tomorrow and find out more as the information I have is a bit unclear...

Hi All - thanks for advice - in the end I had a good quote from a company called NBS Windows for Vrogum 3G windows and a set of outward opening French windows. Will pass on my experience when they are delivered and installed in a few weeks.

I also had a good quote from Rawington for alu-clad triple glazed units, which didn't seem to be set higher than most of the competition, so perhaps 3G and alu-clad are slowly becoming more of a norm than a luxury.

just to add a little - i have magnet trade cat.
8' veneered folding/sliding door list £2364, net £1418
8' oak veneer folding french door list £2182, net £1309
u-value 2.0w/m2k

i guess big question with these products is if manufacturers u-value given is the whole door or the centre pane ?
any idea on regulations guiding this ?

www.fensterversand.com (In Germany): 0.7 u-value 3G with warm edge, 2000mm x 2200m french doors, pine: 1200 Euro.

http://www.viking.ee/uploads/files/vw_tooteleht_3k_eng_web.pdf


PS Is fenster versand joinery available in the UK...? (Also note Ug =0.7 not Uw)

J

One worry I have with direct imports is the possibility of hidden taxes,currency exchange charges, shipping etc...?

Anyone care to comment..?

The only thing I would add is that it seems that folding-sliding doors are quite susceptible to misalignment, leaking seals and mechanical failure. Certainly I know good local builders who've got doors from well known joinery suppliers and had rounds of problems. Whilst there is every chance of a flawless install, if things don't go right getting them fixed can be a pain. The combination of adjustments can be endless.

For that reason, I'd recommend getting your doors from a supplier who will also fit them. That way there is a clear responsibility for getting the job right.

<blockquote><cite>Posted By: arthur</cite>Has anyone tried or know about the internorm windows with the integrated venetian blinds? They seem to have four panes - not sure if that is just because of the blind or if it improves u value too.</blockquote>

1. See http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=527&page=5 - specifically this comment:

"Having toured the Internorm factory in Austria a couple of weeks ago, I have decided to use their Edition 4 windows.

Wood/Aluminium - Triple Glazed with white glass coating (New development that increases solar gain in triple glazing whilst maintaining insulation), and a venetian blind in the cavity between the triple glazed unit and the secondary single glazed pain. Overall U value is 0.68.

The timber is 90% from local sustainable forests and bought into the largest heat/humidity controlled indoor timber store in Europe. It is precut and glue laminated prior to arrival, machines and a computer do most of the work but a nice Austrian lady does the visual inspection !!

Utterly Impressive. "

2. As per the Internorm brochure, there are three models with integral blind: Dimension 4 (UPVC), Edition 4 and Varion 4 (both Wood/Alu - difference is the external profile, the U values are the same). They come in double and triple glazed versions, and the blind is positoned between the double or triple glazed unit and a further pane of glass (the external pane).

3. U window values in the brochure are quoted as a range, which is dependent upon the position of the blind (raised or lowered), i.e. double glazed is 0.99 to 0.81 and triple is 0.72 - 0.63. However, the brochure seems to show that the lower figure is based not on a venetion blind in the gap, but on a honeycomb blind option instead.

4. Internorm state about these windows "For physical reasons, condensation may form on the external window pane in the hollow space that contains the sun protection, under certain climatic conditions" - the prospect of moisture in the gap in a wooden window concerns me, as opposed to dew forming instead on the external pane of a conventional double or triple glazed window.

5. A wood/alu model was on display at Ecobuild last year - I liked the build quality (although I am no expert). I did wonder if the blind and its mechanism would last as long trouble-free as the rest of the window, since people have suggested long lifespans for wood/alu windows. The blind mechanism appeared to be fully enclosed and was operated by a short thin flexible plastic wand on the inside of the frame (when not being used, the flexible wand is secured by a small plastic cleat ). However, Intenorm guarantee that they can repair their products to retain full function for 30 years.

I'd always use an accredited installer for such specialized work. We recently had a similar system installed and we used http://www.dgcos.org.uk who are double glazing ombudsman.

I've just installed a set of softwood Sunfold ones myself. Yes, pricey. Came out about £780 per M^2 incl VAT. I got 4-20-4 glazing which is the max that will fit in their rebates. As they are South facing I figured I'd ultimately probably gain as much as I lost compared to the rather scarce 3g options. (I am 3g on all my East windows and doors though).

Installation has been straightforward, and mechanism is very easy and nice. Seals between doors are double interlocking rubber, and the hinges have great big 8mm stainless pins. I'm not (so far) concerned about sealing or hinges, having studied several other options and chosen Sunfold partly for that reason. I have semi-weathered bottom running track on an alloy cill. Track has external rubber seal, upstand and internal brush.

I was however disappointed that the doors didn't come pre-glazed. Is this common with timber doors/windows?- Perhaps it is. I'm just this moment indoors after much cursing from my less than tidy job of sealing round the glazing units with neutral cure silicone. (It sounds easy, - a nice little rebate left specifically for the sealant in the glazing beads - but woa!). Making a tidy job on the timber/glass silicone seal is one of the hardest breath-holding difficult jobs. I did what I could, but I'm not happy with the appearance of my handiwork. Got to go and do the rest right now..