# External joinery mortice and Tenon methods which lasts longest query



## deema (31 Dec 2021)

Being a bit of a traditionalis, I’ve always made my & M&T joints such that the meeting faces where a ‘perfect fit’, and once together we’re are as far as possible invisible. However, that leaves a sharp corner, at the transition between the long and shirt grain, ie on the edge of the cheeks of the tenons. Paint doesnt stick to sharp corners and over time, the joint can open up at the edge, water get in and it starts to rot. However, the modern way seems to be to add a round over to all edges, such that when the joint comes together there is a v grove at the intersection. This then has v groove protector placed over it which both seals the end grain and also helps to reduce the size of the v groove. There is no sharp corner and the paint / finish will adhere properly. I can see that in theory his is a better way of making the tenon for external applications, but it relies heavily on the v groove protector / filler to keep the end grain dry.

I don’t really like the look of the joint with a v groove, but that’s just personal choice. I have no experience of the longevity of M&Ts made this way, does anyone else have, what’s the view? Old way or new way, which creates external joinery that lasts the longest?

This is the uTube thats got me wondering


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## Jacob (31 Dec 2021)

The old ways produce longest lasting - obviously or they wouldn't still be here to look at.
For windows most common was normal wedge M&Ts, often plus 1/4" pegs through close to the join line, to keep it tightest at the line. But proper maintenance is the biggest issue


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## dzj (31 Dec 2021)

Jacob said:


> The old ways produce longest lasting - obviously or they wouldn't still be here to look at.
> For windows most common was normal wedge M&Ts, often plus 1/4" pegs through close to the join line, to keep it tightest at the line. But proper maintenance is the biggest issue


Proper maintainance...they swear they'll do it, but so much easier to blame the fella that made 'em.


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## Doug71 (1 Jan 2022)

I used to think the sign of quality joinery was crisp corners and invisible joints and this is what I always aimed for.

As you say these days it's all radiused corners and V joints, I prefer the traditional look but the modern way does make sense as paint doesn't stick to sharp corners.

All my external joinery now gets a 3mm radius but I don't do it on the joints for the filler stuff yet. I have been using the Teknos end grain sealer for a while which seems quite good,

I think @RobinBHM used to promote the filling the joint method in the past?


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## Cabinetman (1 Jan 2022)

And there was me thinking the V joint was just on to cover up bad workmanship lol.


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## Peter Sefton (1 Jan 2022)

Cabinetman said:


> And there was me thinking the V joint was just on to cover up bad workmanship lol.



Me too


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## deema (1 Jan 2022)

I do see a bit or rounded corners in joints, but apart from the video not found anyone in my travels that actually does it. Everyday being a school day, I’d love to know if it’s a step up and inwards for widow longevity.


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## HOJ (1 Jan 2022)

deema said:


> I do see a bit or rounded corners in joints, but apart from the video not found anyone in my travels that actually does it. Everyday being a school day, I’d love to know if it’s a step up and inwards for widow longevity.



It is principally part of a design condition for manufactures and forms part of their warranty and service life planning, as generally they are members of the Wood Window Alliance, which has, as well as implementing BS standards, its own specifications that its members have to follow, Jeldwen for example.

"Accoya" also include detailing elements in their "approved user" specifications.


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## deema (1 Jan 2022)

That’s really interesting HOJ, I’ve had a scout around both the Accoya and the Wood Window Alliance, and regrettably (it may be my poor searching) they don’t make public their required standards. I find that rather interesting, as the public can’t actual as a consequence determine if a member has made a product to the standard of the body. I can’t see much if any value as a consequence of the membership, a slight aside, but what am I missing. A yardstick to me is only as good as the measurement it allows you to make, one with no measurement reference is just a stick.


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## johnnyb (1 Jan 2022)

the timber window industry seems like a mish mash of techniques none seem to be tested for longevity or durability beyond seeming to make sense.
surely when making stuff with accoya isn't it a moot point. it's gonna last anyway. more interesting would be using those products with say red deal. how would that impact on its durability?
ejma designed a window that was tested to be superior( although it looked naff)
the scandis designed the hp window using friction stays etc. but none addresses the issue of longevity in non durable species by designing out traps and complete painting.


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## johnnyb (2 Jan 2022)

I posted a similar question and didn't get a single response unfortuneatly.


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## RobinBHM (2 Jan 2022)

deema said:


> I don’t really like the look of the joint with a v groove, but that’s just personal choice. I have no experience of the longevity of M&Ts made this way, does anyone else have, what’s the view? Old way or new way, which creates external joinery that lasts the longest



I spent many years evolving my joinery methods and a V groove at the joints is massively important for longevity of paint.

door and sash rails expand and contract, cracking paint across the joint. With a V groove formed by 2 pencil rounds, there is a full paint film thickness.
I used to use V joint filler, but in fact end grain sealer is fine.


Every sharp edge externally should be avoided, so the same thing applies to edges of sash and frame. Also cill groove where there is an external plant on cill.


Joinery paint suppliers like Teknos, Remmers, Sikkens etc will provide technical advice on joinery detailing for paint.


Every large joinery manufacturer, without exception will do V joints.



Some joinery paints like Teknos are formulated to be pretty soft and will be more resistant to joint cracking than others, like Sigma. But they will all fail at some point.


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## clogs (2 Jan 2022)

getting decent wood is the first problem......
I buy my wood, well the best I can get and store it for at least 6-10months in a covered airy shed, with no sunlight on the wood.....
I used a Sikkens product that was something like oil but dried like varnish...with a slight stain....
just a quick scratch with a Scotch brite type pad and it could be repainted.....
it soaked in really well....all my stuff got at least 3 coats before fitting and another one to cover the finger marks etc once fitted......
It was also excellent when it came to UV damage.....
Unfortunatley I cant buy it here.....but I use something similar but needs recoating every 3-4 years for that fresh look.....
most of my wood stuff suffers extremes of UV and heat with 50degC in direct sun all day for at least 20 weeks.....and it works better than paint......


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## Cabinetman (2 Jan 2022)

RobinBHM said:


> I spent many years evolving my joinery methods and a V groove at the joints is massively important for longevity of paint.
> 
> door and sash rails expand and contract, cracking paint across the joint. With a V groove formed by 2 pencil rounds, there is a full paint film thickness.
> I used to use V joint filler, but in fact end grain sealer is fine.
> ...


 Hadn’t realised that it was an actual pencil round into a V, that’s quite pronounced but I’m sure it does the job, I learnt many years ago not to have sharp edges on outdoor paint work. 
I was referring to the sort of V's you get on interior furniture – which cover a multitude of sins. Ian


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## RobinBHM (2 Jan 2022)

Cabinetman said:


> Hadn’t realised that it was an actual pencil round into a V, that’s quite pronounced but I’m sure it does the job, I learnt many years ago not to have sharp edges on outdoor paint work.
> I was referring to the sort of V's you get on interior furniture – which cover a multitude of sins. Ian



The window tooling by people like whitehill has the option of including a pencil round on the profile and scribe cutters.


On internal furniture, like shaker doors I’ve done it both with and without. If a small chamfer is run along the edges before assembly, then doing it on the tenons is the only option. Done well I think it looks ok.


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## deema (2 Jan 2022)

Is any of this covered by the latest BSI standards for wooden windows and doors? It is many years ago I read through them, and don’t have a copy of the latest version of the standards? I’ve been through the data sheets / technical stuff on Sikkins web site and didn’t find anything about surfaces, I have to say, it may just be me, but I’m finding this very interesting.


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## johnnyb (2 Jan 2022)

I'm also interested being at the stage of making a number of windows having the tackle and the understanding but not really having a proven model to work from( except 100 year old texts)
so many varied approaches its hard to know what's best tbh. one thing I am certain of is wooden windows that look like upvc are largely pointless.( introducing maintenance into an otherwise maintenance free schedule with little discernable aesthetic advantage.


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## deema (2 Jan 2022)

There is an interesting technical specification guide from Jeld-Wen


https://www.jeld-wen.co.uk/getmedia/33e7c81c-1190-4290-9f2c-0c84c636a68e/External-Joinery-Technical-Specification-Guide.pdf.aspx


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## Doug71 (2 Jan 2022)

johnnyb said:


> one thing I am certain of is wooden windows that look like upvc are largely pointless.( introducing maintenance into an otherwise maintenance free schedule with little discernable aesthetic advantage.



There are a couple of houses I work at which have had Accoya doors and windows fitted, the quality is excellent but the spray finish is so good they certainly don't look like wood. One of the front doors has been on about 3 years and it doesn't look any different to the day it was fitted which I guess is a good thing.

Keep it quiet but I have just had 2 PVC windows fitted at my mothers house, they are in a flush casement style (called R7's if anyone interested) and finished in a grey colour, they are really nice and actually look more like wooden windows than some wooden ones I have seen


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## johnnyb (2 Jan 2022)

I think unless we make a large investment its impossible to compete with a proper window specialist. they are really fast. I rely on giving an all round service especially on older house. ie repairs before Xmas i was reproducing a large cyma recta moulding and sham timber frame for around an arts and crafts house involving adzework hollows and rounds leadworking fitting cast guttering etc etc.
joiners up the road make mostly windows and doors including insulated panels. not trad stuff more high performance. lovely stuff and it goes all over the country.


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## deema (2 Jan 2022)

Love to see a photo


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## HOJ (2 Jan 2022)

Information is difficult to find, the BWF have on their site, links to various documents: Publications Archive - The Wood Window Alliance not read through all of them though.

Trada also publish various books on windows, for example: BM TRADA Bookshop

Accoya did do training and supply a folder which is issued to the "user" with information and requirements. I was going to do my refresher last year but it was cancelled.

As Robin has outlined the paint manufactures play a very big part in all of this.



Doug71 said:


> Keep it quiet but I have just had 2 PVC windows fitted at my mothers house, they are in a flush casement style (called R7's if anyone interested) and finished in a grey colour, they are really nice and actually look more like wooden windows than some wooden ones I have seen


Did a big house with the Residence R9's last year (pretty good as well) having done a full cost analysis across a lot of of other options for the client + these were made in Norwich (did try to sell him timber)



johnnyb said:


> unless we make a large investment its impossible to compete with a proper window specialist


 I don't try any more, mine are all for listed/ conservation & in small numbers now


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## johnnyb (2 Jan 2022)

the companies called woodways there not massive and shrinking( 2 partners and 3 or 4 joiners.





Woodway(stoke)Limited | Bespoke Joinery Manufacturing







www.woodway-uk.com


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## johnnyb (2 Jan 2022)

the trouble is ever rising timber costs and manufacturing time. coupled with alternative and cheaper upvc competition. I guess there shrinking as folk move on and training isn't a 5 min job. they've got an scm cnc mostly doing the cut outs for windows and doors( ironmongery.) there's plenty of others around me. piper boats have a big joinery section. oaktree joinery. lymewood Architectural. some are pretty big outfits. many of the old shopfitting places have shut. with them furniture has mostly gone. a guy called alcove makes nice stuff in leek.


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