# Sash windows. Making your own?



## rich7878 (Feb 8, 2019)

Anyone here made their own sash windows?

I need to replace 2 large triple sashes, currently single glazed, with double glazed wood sashes.

Quotes are all over £9000 for 2 windows.

I've read a few blogs and been looking at a lot of posts on some other forums about making sash windows.

I have time and the space to do it.

Eventually I will need to replace 4x triple sashes and 4x large bays. So even a large investment in decent machinery would not be an issue. 

It may well be the case that I can recover some parts of the existing window frame, but the cills and bottoms of the outer linings are all shot. So for now I am assuming I will be making completely new windows.


So looking for advice, tips and hopefully constructive critisism of my plans!


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## gmercer_48083 (Apr 9, 2016)

Wow, making windows is a lot more complicated than making a picture frame. Once you decide on how they are to be made, I suggest you make a scaled down version from cheap materials to see how involved it really is before spending the big bucks. You are entering a very specialized field of woodworking to make your own windows. I made eight single pane windows that measured about 3'x 4' once for a cottage I owned on a lake. They didn't open and I used simple joinery...all sawn on my table saw, using haunch tenons and pegs to join the corners. What I learned is that I had to make all the cuts in a particular order in order to make them. My windows were only a single piece of glass glazed to the wood.

This PDF file shows the basic shapes needed to make a window frame.


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## Steve Neul (Sep 2, 2011)

rich7878 said:


> Anyone here made their own sash windows?
> 
> I need to replace 2 large triple sashes, currently single glazed, with double glazed wood sashes.
> 
> ...


The only difficult thing about wooden windows is the rails where the windows overlap each other. Since they are narrow the joint is done with a finger joint. This could be done with a table saw and a dado set. The coping and sticking of the window can be done with a router. There is router bit sets available for that purpose. 

If it were me I would purchase some pressure treated wood and stack it up and let it dry for a couple months to make the windows. Made out of treated wood you would never need to replace the windows again. It's just treated wood fresh from the store is usually dripping wet and is prone to warp if it isn't dried out first.


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## rich7878 (Feb 8, 2019)

Steve Neul said:


> The only difficult thing about wooden windows is the rails where the windows overlap each other. Since they are narrow the joint is done with a finger joint. This could be done with a table saw and a dado set. The coping and sticking of the window can be done with a router. There is router bit sets available for that purpose.
> 
> If it were me I would purchase some pressure treated wood and stack it up and let it dry for a couple months to make the windows. Made out of treated wood you would never need to replace the windows again. It's just treated wood fresh from the store is usually dripping wet and is prone to warp if it isn't dried out first.


Hi Steve, 

Planning on using Accoya. Its pretty indestructable and very stable. The windows will be painted.

Regarding the meeting rails, the classic joinery books show a dovetail with two tails or a mortise&tenons especially if the are horns on the stiles as there is plenty of material. Sometimes there is a through dowel pin too. Wedges with m&t is another variation, although modern glues are suposed to make this redundant... (how long has the oldest 'modern' glued joint lasted??? Not 120 years!) 

I suppose, a domino could be used these days!

Also traditional sash windows seem to use a stile/rail size of about 38 to 45mm (1½" to 1¾") but modern versions with double glazing are 57mm (2¼") which do make the windows a bit more bulky but gives more room and support for the glass.


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## GeorgeC (Jul 30, 2008)

You say you want to make double pane windows. Are you intending that these have insulation value as is typical of double pane?


If so, do you understand that there is not just air between the panes? How are you prepared to handle that?


George


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## johnep (Apr 12, 2007)

There are online companies who supply kits to make your own windows.
After years of sticking, rotting, and needing repainting, i have had UPVC windows installed. A couple I put in myself at a fraction of the cost of a DG company. Now no problems and streaming condensation a distant memory.

https://www.kitwindows.com/?gclid=C...DjuJk_ZLXzdPlk8fQ5tj-AK5nCGoT1DYaAh0SEALw_wcB

johnep


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## woodnthings (Jan 24, 2009)

*Do you know about Pella ?*



GeorgeC said:


> You say you want to make double pane windows. Are you intending that these have insulation value as is typical of double pane?
> 
> 
> 
> ...



I have double pane windows with a 1" air space between the glass. The inner pane is removable, has it's own metal frame and clips in. There are vent holes in the top and the bottom of the upper and lower rails. I don't know if these are in production any longer, since most newer ones have a sealed space between the glass that's filled with Argon, if I recall?


A 1" air space has an R value of 1, at least it used to .... not much, but it all helps. Windows are the single most inefficient device in the home insulation system, even though there may be a net heat gain on a bright sunny day in BTU's, unless you can store it it won't matter. A properly designed solar house will have a stone or masonry wall close behind the windows to store the warmth from the sun during the day, and it will have insulatiing curtains or panels to cover the windows at night to prevent heat loss. :vs_cool:


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## Steve Neul (Sep 2, 2011)

rich7878 said:


> Hi Steve,
> 
> Planning on using Accoya. Its pretty indestructable and very stable. The windows will be painted.
> 
> ...


The company I worked for had a horizontal boring machine so we doweled the wider rails. I don't know how well you can see the image but the meeting rail had a joint similar to this. We made the tenons smaller and more of them.


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## rich7878 (Feb 8, 2019)

GeorgeC said:


> You say you want to make double pane windows. Are you intending that these have insulation value as is typical of double pane?
> 
> 
> If so, do you understand that there is not just air between the panes? How are you prepared to handle that?
> ...


Hi George, 

I am talking about Krypton filled double glazed units with Low E softcoat. A 12mm space between two layers of 4mm glass gives a U value of 1.2 or 1.1 at the centre.

Building regulations ask for a U value for the whole window (frame etc) of 1.6 or better.

These units are ordered made to measure so all I have to worry about is fitting them to the frames - which appears to be a whole different kettle of fish!


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## 35015 (Nov 24, 2012)

*Welcome...*

Hi Rich,

I will do my best to cover all your query, but if I miss something, let me know? 



rich7878 said:


> ...Anyone here made their own sash windows?


Yes...quite a few and have restored hundreds at this stage of the game in my work as a Historic Restorationist...many over 200 some even 300 years old. 

My specialty is "folk styles" so the last set I made from scratch (aka "green wood") was the design format by a dear friend and colleague for his contemporary barn and work shop...I did the jointing and assembly of his design borrowed from a 1820's Dutch Barn...with his own flair and modifications to the design...

I would also add, I have some great Historic Conservators on your side of "the pond" that are experts in the field and good friends as well...You may find one of them of interest to you:

Peter Ward Youtube Channel

Peter's Company: Heritage Consulting



rich7878 said:


> ...I need to replace 2 large triple sashes, currently single glazed, with double glazed wood sashes....Quotes are all over £9000 for 2 windows...


Any fenestration project can get expensive quick!!! Especially when speaking of custom work...

I'm not sure (even in the U.K.) that a double glazed new lite (aka pain assembly) is required for a vintage window?

If this is a new window and/or not on a listed structure, even then there are ways to meet building code requirements (I think?) with single pain if you are interested...Especially for a period look and feel...



rich7878 said:


> ...I've read a few blogs and been looking at a lot of posts on some other forums about making sash windows...I have time and the space to do it...


Some really great info out there...*BUT!!!...there is also just as much "bad info" as well...!!!*

Vet all sources and any advise extremely well!!! 

Weigh and measure all feedback (mine included) off know proven sources. Check backgrounds, and see what credentials/experiences are before heeding any advise. My C.V. is linked to my business name at the bottom of each post...



rich7878 said:


> ...Eventually I will need to replace 4x triple sashes and 4x large bays. So even a large investment in decent machinery would not be an issue...


You can go the "big machine" route...or...go all traditional (the way the window had been made originally) or mix the two systems together...The choice is yours and what you are comfortable with. If these are windows going into a period building, them my personal ethics are mandated to follow standards like the Burra Convention or organizations like Historic Scotland...

"...like for like...in means, methods, and materials..."



rich7878 said:


> ...It may well be the case that I can recover some parts of the existing window frame, but the cills and bottoms of the outer linings are all shot. So for now I am assuming I will be making completely new windows....


I would have to see exact detailed photos of each window...and...I would have to know the circa date of the architecture they are coming out of...




rich7878 said:


> ...Planning on using Accoya. Its pretty indestructable and very stable. The windows will be painted...


If an "acetylated wood" (aka wood that has undergone the acetylation process of changing the cellular structure) is your choice, then I will assume this is not a historic restored building and/or not something you are concerned with?

"Accoya" is know for being rather expensive but the results thus far for there timber and board stock has been very positive...



rich7878 said:


> ...Regarding the meeting rails, the classic joinery books show a dovetail with two tails or a mortise&tenons especially if the are horns on the stiles as there is plenty of material. Sometimes there is a through dowel pin too.


That is most correct...and if that is what the originals had, I would not recommend deviating from that design too far...unless...you have some rather extensive experience in fenestration design and/or reconditioning of vintage period windows...

I think you are on the correct path with you research thus far it would seem to me?



rich7878 said:


> ...Wedges with m&t is another variation, although modern glues are supposed to make this redundant... (how long has the oldest 'modern' glued joint lasted??? Not 120 years!)


Modern glued joint...no...not that long, but jointed and glued period work is measure in millenia so "120 years" is actually nothing hard to achieve at all...not when the proper modalities are selected and made to work in concert with one another...



rich7878 said:


> ...I suppose, a domino could be used these days!


Absolutely...and exactly how I did the Barn window joinery mentioned above as this was for a contemporary design build but in the vintage motif and traditions of Dutch timber framing systems. However, I'm not a complete "luddite" and will used "free tenon" systems (like domino) which have there own historic roots going back over 4000 years and a well proven tack record of performance...The Domino tenon mortiser just makes a tedious process almost "stupid easy!"



rich7878 said:


> ...Also traditional sash windows seem to use a stile/rail size of about 38 to 45mm (1½" to 1¾") but modern versions with double glazing are 57mm (2¼") which do make the windows a bit more bulky but gives more room and support for the glass.





rich7878 said:


> ...I am talking about Krypton filled double glazed units with Low E softcoat. A 12mm space between two layers of 4mm glass gives a U value of 1.2 or 1.1 at the centre...Building regulations ask for a U value for the whole window (frame etc) of 1.6 or better...These units are ordered made to measure so all I have to worry about is fitting them to the frames - which appears to be a whole different kettle of fish!


If you are going with the "thermal pain" you will need heaver framework within the window design for sure...!

I would caution though (from long experience) I have yet to see a "modern window lite" (aka pain)...or the framework, last nearly as long as a well built and maintain period window frame...with single glazing...Not by a long shot...The "gasses" in these window are usually shot within less than 15 years and replacement is required do to this, or "clouding" and/or related issues...Usually just about the time (or darn near) when any warranty runs out...

As I explain to clients, we design and build our own windows for our archtiecture. They are free to purchase "modern windows" from whom ever they wish...we will not install or warranty them in any way, nor recommend a single brand...

Period windows (well built and kept) have centuries of proven track record...Modern window that "actually work" are usually found in submarines, planes and space craft...They ain't cheep either!!!!...and they don't last as long either...oddly enough?

(Note: I work in metric...its refreshing to see "mm" coming accross a post here!)


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## rich7878 (Feb 8, 2019)

Jay C. White Cloud said:


> Hi Rich,
> 
> I will do my best to cover all your query, but if I miss something, let me know?
> 
> ...





Hi Jay,


Many thanks for the detailed reply!


The house in 1901 and not listed so we are allowed to fit double glazing. I totally understand that it does detract from the look of the house but with such large windows we do lose heat and heat ain't cheap no more! 



We also have significant road noise from agricultural traffic which I'd like to reduce.


Here are some pics:


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## 35015 (Nov 24, 2012)

rich7878 said:


> ...Many thanks for the detailed reply!


My sincere pleasure Rich, thanks for sharing the project with us all!!!



rich7878 said:


> ...The house in 1901 and not listed so we are allowed to fit double glazing. I totally understand that it does detract from the look of the house but with such large windows we do lose heat and heat ain't cheap no more!


Well...she is a sweet little thing...isn't she...!!!...turn of the century British Edwardian architecture with some eclectic elements if I was guessing?

I'm a "staunch and stuffy" Historic Preservationist...LMAO...when I have to (or need to) be so...but we can't save everything, nor do folks have the time or money to hire and/or learn everything they need to do it..."the period way." So no worries here, and it looks like the poor thing has already been dragged down the road of "modernity" anyway...???...As such, your work will be a kind improvement in making her more comfortable and livable for you and your family...

I would still offer a lot of the same advise, because "old style windows" when well made and maintain still beat the pants off of modern window when all elements of fenestration design, build and implementation is taken in to properer consideration...



rich7878 said:


> ...We also have significant road noise from agricultural traffic which I'd like to reduce.


All I can say to that is..."window clothes"...more on that later if you wish (??) because its a key element to why most folks think "modern windows" are better and why period window actually are...typically...



rich7878 said:


> ...Here are some pics:


Thanks so much for sharing those!!!

I can now see none of the windows have individual lights in them and are full sized pains. That would lead me to believe that none of these are the original windows and/or have been remolded sometime in the past before?

Thanks again for sharing the project. I look forward to following along and helping anywhere you wish to have some assistance...


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## woodnthings (Jan 24, 2009)

*So, after all that discussion ......*



rich7878 said:


> Hi Jay,
> 
> 
> Many thanks for the detailed reply!
> ...



Do you intend to mill your own sections using either a shaper or router table OR can you purchase factory made units and make the mullions and casings in order to use standard sizes? That would be a middle ground, cheaper in some ways, but still practical. I designed a custom home in 1980, configured the location of some 40 double pane windows made by Pella and ended up relocating every one except one. I am good at moving widows about by now, but I'm done with it. :|
Your project would be similar in that you would remove an existing set of windows, install the new ones and frame in around them without changing any structural elements. In my case I reframed openings, added headers, added sliding door walls, added steel beams to support additional floor loads and increased spans so 
my project was way more complex. 

Whether you choose to use individual multi-paned windows OR make a faux frame that looks like multiple panes, is another choice that will save time and money, since one large panel of glass could serve as the basis. Of course this "violates" all traditional and historical restoration aspects, BUT it's still a choice your seem to have available. Good luck. :vs_cool:


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