# External Bi-Fold doors - some advice please!



## RogerM (30 Mar 2011)

We're planning a kitchen/breakfastroom extension for later in the year so went along to the Home Building and Renovation Show at the NEC last weekend. Big mistake to take "the boss"! She's set her dear little heart on bifold doors with a matching patio area outside. I must admit it has it's attractions until we start pricing bifold doors. A panel of 3 in European Oak to fill a 2800mm gap was typically around £4,400 - delivered but not fitted. No prizes for guessing what comes next!

I can't find any threads on exterior bi-fold doors. Anyone here made some? I have priced toughened Planitherm sealed units, 4/20/4 with an argon fill at £108. I'm waiting for a quote for the Centor F3 bottom rolling track system, which is the latest system from Centor, also demonstrated here, and looked and felt superior to the top hung systems, but guessing that there will be no change out of £500. But assuming an overall cost of around £850 for hardware and sealed units, there is plenty of scope to make a decent set of 3 doors for around £1,200 - £1,400(ish) in Oak or Iroko, enabling me to keep £3k in my trouser pocket which is where I'd prefer to keep it. 

All the doors on display at the NEC were around 58mm, laminated from 3 layers of timber. The outer layers were obviously in one piece, but the middle layer was sometimes in 2 or 3 pieces. All the sales guys said that laminating up in this way made for a more stable frame, resistant to splitting, twisting and warping. I can sort of see that, but is this also just a cheaper alternative to using well dried solid timber? If you were doing the job, would you use solid or laminate up in 3 layers? And if so, using what glue?

Then there is the question of blinds - which opens another whole can of worms. There were some very impressive systems on display with blinds sandwiched between the glass panes inside the sealed unit. Logic tells me that if these can go wrong, they will. This is partially born out by 2 glazing firms who tell me that they try and avoid doing these at all costs. They only offer 12 months guarantee on the blinds, whereas there is a 5 year guarantee on the sealed unit, but if the blinds goes wrong after 12 months you're in to paying for a new sealed unit. One of the sales guys was telling me that they had to replace every panel in a conservatory before 2 years was up, which kind of says it all. Again - any real life feedback?

My gut feel is that I can do this - but would welcome a bit of constructive encouragement and advice from you guys!


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## knappers (30 Mar 2011)

We looked at oak bifold doors about 3 years ago - we were looking for 2 x 5 door sets!! In the end we went for aluminium framed ones, as the aspects we wanted them for are south facing, and we figured we would be safer from wood movement that way. Did cost about £14K though!! The chap next door went a different route, and had his made from softwood - they have move like a pineapple.

Si.


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## jasonB (30 Mar 2011)

I've just had a quite for a 2.7wide 3 door from Kloeber at £3600inc VAT plus fitting. These are for engineered oak, don't think I would want to risk solid, just too much risk of movement.

Just been looking a the job with the structural engineer and looks like we are going to raise the height from 2100 to 2400 as the client wants a bit more light, should add about another £4k to the job with the amount of steel he wants to put in plus the other associated works

I would think you will be looking at more than £500 for the door gear, Ironmongery directs stuff starts about £700 for 3 doors

J


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## tomatwark (30 Mar 2011)

I would not risk solid either as they will almost certainly move and cause problems down the road.

I also look at how you have to machine the doors to fit the track, unless you have the right kit it may be a real pain in the backside to get right. 

In the factory these will almost certainly be made using CNC to a very tight tolerence.

Tom


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## Dibs-h (30 Mar 2011)

Home building & renovating show is aimed at retail. You want to look at Interbuild - that's aimed at the trade and the prices reflect it.

I went a couple of years ago and the prices for the hardware were very impressive (on the low side). Did get a lot of bumf including prices, but they're all in a super safe place. Will be digging them all out at some point soon as some one else wants the details. As soon as I get them out - I'll drop you a PM, but it's likely to be at around a month or so.

HIH

Dibs


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## Dee J (31 Mar 2011)

Would like something like these bi-fold doors myself... Though I gather building regs for home-built external doors or windows is a bit iffy - anyone got experience of that?

Dee


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## RogerM (31 Mar 2011)

Thanks for the pointers guys. Whilst I still haven't got the quote from Centor, I'm guessing that a full 3 door hardware set will be nearer £800 - I'll let you know.

Kappers - at £1,400 per door that is why I'm looking at doing it myself. Bet they're nice though!

Jason - The Kloeber doors look nice, and just a tad cheaper than some of the other offerings we saw. 

Tomatwark - section doesn't look particularly complicated on the pdf off the Centor website. Certainly nothing that I wouldn't feel happy to tackle using my router table and Incra Fence. 

Dibs-h - thanks for the offer of prices by pm. 

Dee - still need to read the fine detail re the building regs side of it, but I'm sure I recollect reading somewhere that for fully glazed doors, provided that the glass meets the U value requirement then the U value of the frame is ignored. There may be a bit of homework required here but nothing that is insurmountable. 

We also need a new fully glazed back door, so feel inclined to give that a try to see how I get on before committing to a full set of bifolds. Jonnyd posting in another place has pointed me to ready laminated engineered oak from either Brooks Bros or Timbmet TEC which could take some of the angst out of laminating up my own sections although at £27.78 per metre it isn't cheap, (that's over £5,500 per cu m or £154 per cu ft) - but of course there would be minimal waste - and it ought to be really stable stuff - but I think I'm tempted to make up a metre of my own using some oak offcuts just to see what the process and end result is like.


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## Offcut (31 Mar 2011)

My friend had a set of bifold door made by a joinery firm using centor running gear. After I looked at the doors, really the only specialist parts were getting a cutter to create the slot for the door seal. Each door panel was created in the usual mortise fashion and the door gear screwed on to it. Template for the router or sharp chizel to create a 3mm rebate to allow a flush mount. Centor do a good dimentions guide on their website. His doors were top hung and had a guide pin at the base that ran in a 25mm wide by 35mm deep groove in a 60mm wooden door sill.

here is the company http://www.slidingsash.com/
I have no interest in this company so do your own research

The doors were very well made though


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## RogerM (31 Mar 2011)

RogerM":1swztnxq said:


> Thanks for the pointers guys. Whilst I still haven't got the quote from Centor, I'm guessing that a full 3 door hardware set will be nearer £800 - I'll let you know.



A 3 door hardware and rail pack for the Centor F3 system comes in at £628 inc VAT. If I laminate my own timber, allow £100 per door, plus toughened Pilkington Planitherm argon filled units at £108 per unit, and we're looking at about £1250 for a 3 door set - maybe £1300 by the time I've added finishing etc.


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## RogerM (14 Oct 2011)

My windows and folding sliding doors project is getting very close. I've made the 2 replacement windows that go in the gable of the original house as per my other post, and have just started on the single window at the back of the extension. This will be very similar to those already made so I'll not put a detailed WIP up for that one - although happy to answer any questions.

There will be 2 sets of folding sliding doors, both top hung using Centor E3 gear suspended from the flitch beam which is solid enough to hang a battleship from. One set on the right will slide back from the post on the right back against the house on the outside, and should be relatively straight forward as the jamb will be against the wall. This will be the first set I'll build, and I'll put up a WIP here.







The second set will slide to the left, and will have a 2 sash window between the folding door jamb and the left hand steel post. I'm struggling to envisage how the door jamb and the window will meet. The window frame is 90mm thick, and according to the spec from Centor, the door jamb would normally be 154 mm thick (outside to inside) if the door is 54mm thick. This leaves 64mm of door jamb that will extend past the window frame. As all the weight will be supported by the flitch beam, I can't see there is any need for the door jamb to be excessively heavy as its only purpose is to stop the last door sliding down the track. However, just leaving a simple 25mm jamb projecting beyond the window frame will look clumsy and a bit mean. On the other hand a large section post extending below the window cill will look very heavy.

I can't find any photos of this arrangement to provide inspiration, and at the same time don't want to reinvent the wheel as I'm sure this will have been done before, and well. Any ideas gratefully received. I'm well outside my comfort zone here - although hopefully not completely out of my depth.


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## jasonB (15 Oct 2011)

Had similar issues with the Klober ones I mentioned above 149mm vs 99mm where the window met the door but this time at an angle. I opted to have then with the outer faces flush which would probably be best in your case as then its only the window/door joint that will need sorting as the lower half of the door frame will just be against the short wall. 

You could consider using the door jam as the window jam as well or just having one side of the window made with a wider jam so the two frames butt up flush.

J


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## RogerM (29 Aug 2012)

Hi (Mod Edit:---) and welcome to the forum. Thanks for the advice but I actually solved my problem so far as bifold door configuration is concerned some time ago and I wrote it up as a work in progress (WIP) * here*.


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## renmos (11 Jun 2014)

Hi re wood byfold doors I've made dozens of sets in oak and mahogany also in iroka used henderson gear very dear . Tomfold from quest works well . As far as laminated vs solid goes I've tried it found some warped before starting the job.i now hand select straight grained timber from local timber yard brook bros maldon essex. Oak is the wors for expansion. Also not good in full sun. Most doors I make are in utile mahogany painted. Ihope this may help . Any think else just ask.been a joiner for 48 years.


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## RogerM (11 Jun 2014)

renmos":wewmbi7k said:


> Hi re wood byfold doors I've made dozens of sets in oak and mahogany also in iroka used henderson gear very dear . Tomfold from quest works well . As far as laminated vs solid goes I've tried it found some warped before starting the job.i now hand select straight grained timber from local timber yard brook bros maldon essex. Oak is the wors for expansion. Also not good in full sun. Most doors I make are in utile mahogany painted. Ihope this may help . Any think else just ask.been a joiner for 48 years.



Welcome to the forum renmos. Thanks for the input. I actually went ahead with the top hung Centor E3 gear and built the doors in 3 laminations of iroko as described in * this thread*. Two years on they are working as well as on the day they were installed and I haven't had to make any adjustments in between, so the whole setup seems to be stable.

One set of doors rarely gets the sun, and the other gets afternoon sun. If you were to make a set of doors for a full sun position and wanted to retain a natural wood look rather than painted, what timber would you use?


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## renmos (11 Jun 2014)

Hi roger . Re doors doors in full sun. Oak looks great when new very stylish. But most people just don't keep up the maintenance. Thats when the fine cracking starts and joints start to open .im a iroka fan rather than oak . A lot cheaper and more durable. If you dont mind a darker wood utile mahogany is stable timber .not its close brother sapele .harder more likely to warp . I've tried all sorts of finishes but most dont really last more than a few years . Just started to use oswax exterior. Hope it as good as interior one .when I make mortise tenon doors on the out side shoulder I use biscuit joints as well 1 on 4inch heads 2 on 8inch bottom rails. Hope this may help renmos.


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## RogerM (12 Jun 2014)

Thanks renmos. I ended up using Sikkens. You may find *this thread* comparing the relative durability of Osmo UV Oil to Sikkens Filter 7 of interest.


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