Window sash width vs side jamb width

Bob Beasley

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I'm trying to understand window anatomy. Is it correct that a window sash fits in a window jamb?

If so, is the window jamb made up of a: Head,Sill, and two sides?

Using the above terminology, how much wider should the distance be between the side jambs and the sash be to allow for movement? I'll be using cypress if that matters.

Thanks!
 
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Some variables here. Interior mill work is subject to various architectural styles, and of course there are no real hard and fast rules. I Googled 'window and door trim' in Amazon books and found all sorts of interesting reads for less than $20, some written by the pro interior mlllwork guys. Good luck learning new stuff!
 
Mine is a 1896 cypress Acadian Cottage. I'm trying to duplicate the original windows. I think they were built on site out of construction left overs. Over the years someone replaced two of them with eh...gad.... aluminum windows.

Not that I'm proud of my little cottage or anything BUT it made it's TV debut Tuesday on NCIS New Orleans season 2 episode 2. I'm having a blast learning all this stuff. And buying cool power tools.

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Bill offered good help with terminology. If you are conversant with SketchUp (worth the learning curve), draw out your existing door mill work and then duplicate it around the existing window sizes and see what it look likes on your screen. I would not be surprised to see door casings the same width as window casings. Jambs would be a consistent ratio of the casings. Go from there and see what happens. I'd measure Bill's drawing to determine ratios, draw them out on the screen and see how it all looks. Don't overthink this. The original builders were likely not Rhodes' Scholars.
 
Hey Bob, good on you for keeping the old windows alive. So many folks think the new ones are better when it just ain't true and there's a lot of value in those old windows.

The preservation trust and some related folks are holding a class local to me (http://www.thedalleschronicle.com/news/2015/sep/25/old-windows-get-new-life/) on restoring old windows. I don't think I'll be able to make it to that one unfortunately, but while looking at it I found what I think is the main teaching material they're using http://blog.preservationleadershipforum.org/2015/07/31/review-window-sash-bible/#.Vg2jbZc8rmE (amazon: http://www.amazon.com/gp/product/1505299144) which I may well pick up.
 
I think I would take on that challenge, and I would do just like the original builder did, with ONE exception. I would purchase some high quality tracking, and some high quality double pane thermal windows. There is a remarkable difference between the new windows and the old single pane windows in both hot and cold.

I would built them on site but not with scraps.

I would compare the original window and duplicate the construction, but incorporating the new design features. You can measure and duplicate the original pieces.

I would make the new windows "look like" the old windows but with enhanced performance.

Tilt out windows are a GREAT design - if I could build that feature in, I would.

That stuff is not all that hard to do, but it does take a little patience, and a good miter saw and table saw. A good jig saw is handy also.

Use the Great Stuff foam for doors and windows (blue can).

With a little ingenuity and patience, you can make some great high performance windows that will be indistinguishable from the originals.
 
would purchase some high quality tracking, and some high quality double pane thermal windows. There is a remarkable difference between the new windows and the old single pane windows in both hot and cold.

Yes and no. The double pane are better than the 1950's era single pane, single window setup. They are generally not better than the older single pane plus storm window design.

http://www.preservationnation.org/i...lab/saving-windows-saving-money/#.Vg28GJc8rmE
specifically:
http://www.preservationnation.org/i...saving-money/WINDOWS_PGL_FactSheet_100212.pdf
breaks down the savings for the various types of updates.

Somewhat anecdotal (but supported by other data I'm to lazy to look up at the moment):
http://blog.preservationnation.org/...linley-proves-old-windows-worth/#.Vg286Jc8rmE

Short version is that, yes double pane is better than single pane but not necessarily as good as single pane plus storm window (which effectively makes it a double pane I suppose but with a larger air space). This is assuming that all of the windows are well made of course, I think air leaks around the edges could quickly overwhelm the other variables.

The other consideration is that double pane windows leak gas at some measurable rate (yes they can be recharged but who's going to do that?) and once that seal is broken you have problems with fogging, etc.. The single pane ones are more easily fixable. That's obviously only a consideration for certain types of us :D

Tilt out windows are a GREAT design - if I could build that feature in, I would.

I'm on the fence here... its certainly a personal preference I think. I think I get better airflow with my current double hung windows than we did with our last house that had fancy swing out Anderson windows. I also believe that the double hung seals better on average (exceptions abound I'm sure). The other advantage of the double hung is that they are better at surviving high speed gusts when open (that was a bit disconcerting to find out the hard way - of course not every place has ~50-70mph gusts on a daily basis :D). The swing out arguably has simpler parts though so.. I'm not sure.

What do you see as the main advantage(s) of swing out?


BTW: if you can get cypress wood for your windows its pretty nice for being rot resistant and sturdy (especially the heartwood). We don't see it around these parts but you might :D Even pine properly painted and cared for lasts a long time though.
 
I have new Marvin windows on the South side of my house - no storm windows.

I have single pane windows with storm windows on the north side of my house. I have not gotten to them yet.

I am 100% about the difference. There is a remarkable difference. Mostly noticeable in the winter. There is no mistaking the difference. Even in the summer with windows closed and A/C running, there is still a noticeable difference in the windows.

I burn firewood for heat. Having heat loss from the windows is not an issue to me. If I was still burning oil for heat the single pane and storms would have been long gone.

I grew up in older houses. I will take the new!!

Also on the tilt in - there are good ones and not so good ones. Personally - I do not like Anderson windows.
A good tilt out window makes cleaning a very easy task.

I had sliding glass doors that frosted on the inside, even though they were double pane. They were inexpensive doors without thermal breaks. When I built my addition I installed Marvin Integrity, not even the top line. I did shop around and do my homework. I also learned a lot about doors and windows when I ran my handyman franchise. It can be 0 degrees outside and windy and my doors and windows do not feel cold to the touch. That is not so with the single pane with storms.

I have never seen a single pane window perform in the same way, even with storms.

All my windows are double hung.
 
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There's some really good information on window maintenance and repair here as well (obviously haven't read all of it, or even most but looks pretty interesting):
http://historichomeworks.com/forum/viewforum.php?f=16


The Andersons we had were the "swing to the outside" casement version. It was a pretty hot area in the summer and we couldn't get them open far enough to really allow the breeze to blow straight through (they'd go to maybe 60d instead of 90d or more). The swing ins look like they'd alleviate a lot of those problems, so definitely filing that away for future thought..

You're certainly correct on the ease of cleaning aspect of the tilt in windows., especially on the upper stories - worth keeping in mind!

I hear you on a lot of the older house issues - when the wind goes in one side and out the other it doesn't matter how cool the hand axed logs look :D Having said that there is imho a lot of trade offs between short term and long term maintainability that make the whole conversation .. complicated. Its certainly true that some older stuff was well made and much was most certainly not and a lot of the stuff that was could certainly use a lot of repair and maintenance at this point.

On replacement costs I'm still having some difficulty figuring the savings for the general case. For new windows it seems to generally make sense to get higher E windows (although the math on what specifically is better is complicated there as well, and depends on the window types/environment). If you have giant picture windows in a cold climate then likely new window there is a no brainer from a comfort perspective but just figuring for "normal windows" I'm not convinced :D

I'm looking at the U values (measure of heat transfer rate) for various glazing types (for example: https://www.wbdg.org/resources/windows.php about half way down the page has a nice chart that seems to line up pretty well with other data I'm finding such as http://www.aspenpitkin.com/Portals/...ode/1993 ASHRAE Fundamentals Ufactor only.pdf) and the best glazing types seem to be around 3x better than single pane (until you get to the crazy stuff, but that's only the center of the pane U factor the overall window construction matters a lot as well).

Using exceedingly rough math we can get some completely bogus cost saving estimates (hows that for confidence :p). Most window mfgs publish some sort of U values so it would be better off plugging those in and doing the math for any specific house, the example I'm pulling out here is only very roughly illustrative. Baseline numbers I'm using are (rounding slightly) single pane U of 1.06, double pane U of 0.5, triple U of 0.3, and best in class might have a U of 0.1 or so. I'm figuring window heat loss should be 20% of the total house heat loss as an extremely high guestimate assuming that the house is somewhat normal construction (20% might be a baseline for a house with a LOT of single pane windows in really poor maintenance, normal is likely closer to 10%). In theory if storm windows were 100% effective you ought to be really close to or perhaps better than double pane, of course the enclosure likely leaks more than a well installed double so say U of 0.75 or so (imho that's highly pessimistic but I'm biasing the data against my assumptions, the ASHRAE numbers I found penciled out closer to ~0.55U or even less depending on the storm window type).

Using those numbers to start with we'll assume that ~20% of the heating/cooling cost is going out the window with single pane and no storm windows as the baseline with a somewhat arbitrarily chosen yearly heating/cooling bill of $1000 to make the math easy.
WindowEstimated Usavings over baselineyearly energy savings<br>(arbitrarily chosen $1000 baseline)
Single pane no storm1.06U0%$0
Single pane with storm0.75U5%$50
Double pane0.5U10%$100
Triple pane0.5U14%$140
Crazy reflective low E super triple pane with some sort of exotic gas0.1U18%$180

Assuming ~12 windows (which is what we have in our house, not counting the sliding glass door which is an energy pig as well) and a cost of $500-1000 per window (depending on how fancy you get, including installation for that price..) that's $6,000 to $12,000 to replace all of the windows.

So even at the best case where I managed to use get the 0.1U windows for $500 per (unlikely) its still 33 years to pay that back :eek: If we assume a more average cost of say $10k for the triple pane at $140/year that 71 years to payback. Even if you could get the 0.1U windows at $250 (extremely unlikely) its still over 15 years...

So unless your heat loss is way higher than I'm figuring (certainly possible) or there are other confounding factors (also possible), the math on replacement versus repair gets kind of hard to figure imho; especially given the expected lifespan of most windows (less than the payback time looks common - I'm seeing failure estimates for the seals in double/triple pane windows in the 25-35 year range).

A somewhat more pessimistic study can be found here: http://www.oldhouseguy.com/assets/StudyReplacementVsHistoricWindow.pdf - imho its a bit biased against the replacement numbers but still its interesting to walk through.

This is all at odds with what the window salespeople claim: http://www.efficientwindows.org/energycost.php - I can't figure their math though.. the only way it seems to work is if they're figuring the % savings on the windows against the whole house cost (but maybe I'm just doing it wrong - in which case someone please say so :D). Supporting my math: http://www.traditional-building.com/Previous-Product-Reports/3-windowsJune2008.htm - more support: https://heritage.utah.gov/history/windows (even figuring 25% total savings the math wasn't very good there).

I'm also discounting some classes of comfort issues which can be worth the expense :D If the window feels cold (especially to the other interested parties) the math starts to matter less ;)
 
It seems geographic location complicates the upgrade decision further. I live in the tropics of South Louisiana where our winters are laughable compared to many folks. For the summer heat, which we think about more, the cottage sits on a knoll under a canopy of live oaks. It was clearly built to take advantage of prevailing breezes and available shade. The closest asphalt or concrete is more than 1/4 miles away. It's not the type of building that lends itself to being sealed and controlled.
 
It seems geographic location complicates the upgrade decision further. I live in the tropics of South Louisiana where our winters are laughable compared to many folks. For the summer heat, which we think about more, the cottage sits on a knoll under a canopy of live oaks. It was clearly built to take advantage of prevailing breezes and available shade. The closest asphalt or concrete is more than 1/4 miles away. It's not the type of building that lends itself to being sealed and controlled.

Cypress should be plentiful (and cheap!) in your area. It's also a very weather-friendly wood that'll weather very well in your area. It'll turn a nice silver-gray to blend in with the rest of the cabin within a couple seasons. I'd build the window frames, sills, sashes, etc. out of cypress. They shouldn't be too hard to build. Double hung windows are what were likely original to the cabin, so that's the way I'd go. If you want the (minimal) heat reflection, you could custom order some double pane 'Low E" glass panels. Otherwise, I'd just use double strength, single glass in them.
 
Cypress should be plentiful (and cheap!) in your area. It's also a very weather-friendly wood that'll weather very well in your area. It'll turn a nice silver-gray to blend in with the rest of the cabin within a couple seasons. I'd build the window frames, sills, sashes, etc. out of cypress. They shouldn't be too hard to build. Double hung windows are what were likely original to the cabin, so that's the way I'd go. If you want the (minimal) heat reflection, you could custom order some double pane 'Low E" glass panels. Otherwise, I'd just use double strength, single glass in them.

That's the plan. Only the bottom sash opens in the original windows and they're not counter balanced.

I've become a cypress hoarder, problem is I've got lots of company. Hard working folks do tear downs for their cypress, less energetic folks like me have to buy it. I'm currently paying $3 to $6 per board foot.
 
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