Convince me not to make my own picture windows
Tiziano
| Posted in General Questions on
I’m in need of 5 picture windows for a detached studio/shop (1 at 48″ x 48″, and 4 at 30″ x 36″). Due to cost I wonder whether I’m better off building them myself. I have access to a complete shop and am moderately handy. Plus, my neighbor was a cabinet maker before he retired. I’d order double or triple panes from a local glass shop.
25 years ago I had to build one due to its trapezoidal shape. As I recall I framed the RO, sloped the sill, and set the double-pane glass into the frame from the inside. I then attached an interior frame to keep the glass in place. Finally, I caulked the outside edges. It still seems work fine, though what I’m proposing would be a bit more advanced.
I’ve looked through all the Google hits on window anatomy, manufacturer’s sites, etc. and see a lot of complications. The attached photo is my favorite one (sarc). Clearly there are valid reasons for all the complicated shapes and intersections and in my ignorance I’ll not question them. However, for my needs, am I wrong to think that much of it could be simplified?
The sill slopes down to drain water. The glass sits in a frame such that it allows the frame to expand and contract with the weather. The joints between the glass and the frame are sealed on the outside to keep water out.
What am I missing?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
Tiziano,
If you have the skills to mimic a well made wood window there is no reason not to make your own - except you end up with windows with wood on the exterior, which don’t have great longevity compared to clad ones.
That’s a different project than setting glazed units in the RO and then trimming them out, which is bad idea for a variety of reasons.
Malcolm --
What about making the exterior pieces out of Azek or similar?
DC,
Maybe, if you could work out a solution to their continued movement. It all sound doable but complex. Semi-professional backyard workshops around here pump out everything from doors to countertops. I haven't seen anyone doing windows.
Might be a good use of TruExterior trim (formerly often simply called "Boral"). I probably wouldn't try to make an operable window out of it, but a frame and some stops combined with an IGU, why not?
Azek competition I think. Either one seems like something I should think about.
"That’s a different project than setting glazed units in the RO and then trimming them out, which is bad idea for a variety of reasons."
I figured as much. I see a number of YouTubes and at least one older FH article but making your own seems to be very old school - like the 1930s.
Any thoughts on how I'd educate myself a bit better?
I've seen this: https://infinitytools.com/blogs/blog/how-to-make-a-window-sash-part-1
And this: https://www.finehomebuilding.com/2024/01/01/making-window-sash
Tiziano,
I built and maintained a score of cabins like this at a nearby resort for over 20 years. The cedar windows on exposed faces of the buildings almost all experienced problems in the same spot, which was at the jambs and sill where water could get behind the exterior wood glazing stops. That seemed like the weakest part of wood windows. Bedding the stops in bituminous glazing tape helped a lot. With regular refinishing the frames did okay.
Beautiful!
Malcolm,
If I'm understanding right, the glass panes were held in place by wood stops on the exterior? I wonder if some of the water infiltration could have been avoided by using glazier's putty?
In a past life I spent a fair bit of time rehabbing old, old wood windows, and the glass in most of them was pushed up against an interior frame/stop, held off the frame slightly on all side with glazier's points, and then finally held into place with tooled glazier's putty, which was then painted. Seemed like the painted glazier's putty could take abuse from wetting fairly well, and tooling it allowed everything to slope away from the glass for good drainage.
How is your 25 year old installation doing? Because thats pretty good! Is it because the new ones you want to build are bigger that worries you? I wasn't sure what you meant by more advanced...
Needed a some recaulking and painting now and then. It's facing north, under a deep eave and a large tree so it never gets sun and doesn't get wet that often.
By 'more advanced' I meant not simply setting the glass in a trimmed RO.
I live in a house with site built window frames, they are redwood, and have 2 foot overhangs.
They are unharmed in 50 years.
I will try to make a little drawing to illustrate how they are made.
rough section of the window frames in my house. In my house the siding slides into the groove on the outside, but this is unnecessary and a PITA. A 1/8 saw slot that is well outward of the surface of the siding will prevent water running back along the surface
The inside detail is again part of the trimless look of the house.
No interior or exterior trim
The sides simply have a rabbet for the glass. The bottom 'shoe' of the window is rabbeted for the sides. I only made one myself in order to move an interior wall. One could clear the corner of the sides to avoid leaking, but in practice it has not leaked.
We built 4 sliders of similar style and they are watertight.
Thanks, and the drawing really helps.
This conversation reminds me of a movie based on a true story, if I remember right. I checked on yu tube and it is there free now. I just typed in Still Mine full movie. It is from 2012... It is from the point of view of people like me, and sounds like some others...
Does anyone know what this means?
"The 2018 IRC requires site-built windows to be tested for design pressure in accordance with ASTM E330. This standard was updated from the 2002 edition to the 2014 edition in the 2018 IRC."
It means there's a good chance you won't meet US building codes because of the cost of testing the design pressure. Unless, that is, your jurisdiction has eliminated that section of the model code, or you live in a place where codes aren't heavily enforced.
That's kind of what I thought. Unfortunately ASTM doesn't make their standards available online for free. I'm wondering if it's something like the IRC where there's a prescriptive path, or you can do your own design with an engineer's stamp. Or if you actually have to submit your windows for testing.
It just seems weird that site-built windows would have to be tested, unless it's a backdoor way of saying that site-built windows are prohibited.
I believe it's mostly the latter, as outside testing would get expensive, but it's possible.
DC,
On top of each manufacturer's windows needing to pass a pressure test, many large projects here, especially those with curtain wall systems which are assembled on-site, specify that a percentage of the windows on site need to be tested too. A whole testing industry has developed around those requirements.
So the answer to the OP's question is if code is being enforced where you are, you can't.
I kinda live in the woods, but it is Massachusetts, and the code enforcement is focused on the house not burning down, and the checkboxes being filled out on the application. I mean, the plumbing inspector, who I was friendly with, stopped in when he saw an out of town plumbing truck in the drive. Turned on his heel when I told him it was heating. Still, would they know or care about this code provision?
Only updating I was required to do[15 years ago] was wired smokes and AFCI breakers. All the insulation was my call. OF course if I had asked the question...or I imagine there are CEOs who are like that.
I seriously doubt a shop reno is going to raise an eyebrow.
Mostly the purpose of renovation building permits is cash flow, but it would all depend on your local CEO.
I took apart a site built window a while back. Maybe 15 years old with minimal overhangs. It was in surprisingly decent condition, obvious issues were at the exterior bottom glass stop and the sill. Both of these were pretty soft from rot.
Not too hard to fix those issues though.
If you are doing site built, make sure to slope the sill, space the IGU off the sill and add some weep holes to allow drainage to the exterior.
The spacing the IGU off and drainage is important as edge seals sitting in water will corrode over time.
This brings up a point that I don't yet follow.
Why separate fixed window unit from the wall structure? I mean, doing so adds joints and intersections that I imagine increase the chances of water and air infiltration.
Tiziano,
Conceptually the cladding - rain-screen, WRB, etc - are there to protect the structure of the house - and the windows and doors should be seen as part of the cladding. At openings the idea is to separate the framing from a replaceable element that handles possible bulk water intrusion. The gap between the RO and window works as a drainage plane for any water that does make it though. That's why it's important to provide a sloped sill-plan and path for that water to move to the exterior.
Do you get much rain in your area?
Here is one potential argument against:
You might be able to buy vinyl windows at a Habitat for Humanity Restore or an architectural salvage yard for cheap enough that it wouldn't make sense to build your own.
Rain, snow, humid, hot, cold. Zone 6, Minnesota.
Just curious but where does zone 5 apply in Minnesota?
Fat fingers on a small iPhone screen typo. Corrected now to Zone 6.
Thanks, that makes a lot more sense, and I can relate to typos.
I also live in a house with 40+ year-old site-built windows, still in great shape _but_ we do maintenance and live in a dry climate. I have several friends that have constructed windows from IGUs with good success where they take care of things; not so good where the wood has dried, cracked, warped, and the windows leak. Conservation Technologies sells appropriate gaskets and provides advice. Wood windows, especially south-facing where I live, require considerable routine maintenance. If your windows are protected from water, and you're good with maintenance, you could certainly design and construct an efficient and long-lasting window. However, the box store prices are so low that you won't get much for your labor.
I'd say the main downsides are the time required, the lack of energy efficiency you'll be able to achieve and the need to maintain wood windows. I have built and/or restored several traditional windows and it's easy enough if you have a basic shop, though there are several challenges.
I few years ago I also redid direct-glazed windows built in the mid-1970s. I resisted my clients' wishes for the reasons given above, but other than the old sealant being a bear to remove, I'm happy with and confident in the assembly and would consider doing it for myself to save money.
I will say that just because your friend is a cabinetmaker doesn't mean that he knows windows. I designed a major renovation to a house built by a cabinetmaker in the 1980s and his windows were warped and some were rotting.
Understood. Thanks.
one should also note my caveats above. Mine are made of redwood, pretty common in 1970, not so available now. 2 foot overhangs and upstairs overhangs 2 feet in every direction, downstairs windows are 4 feet from the drip line.
My last house had a 5 foot Brosco drop in door unit, built in 1990. I bought the house in 1997. Bottom of the sidelights were rotten by mid 97. All that kind of stuff from the 70s on, probably plantation grown 'white wood'
Mahogany, Cedar[kinda soft] or carefully selected Doug Fir would be the choices
None of which they give away.