Building efficient fixed pane window
Patrick60
| Posted in Energy, Heating & Insulation on
We are building a home with a wall of South facing windows. They will not open. Because of there size and qty, it’s expensive. I’d like to to build them. First I would be using good quality glazing. I would like to use a high density foam as the frame. Dowmakes a range of foams, 15 psi is standard sheeting and 25 psi is for under slab. Dow makes up to 100 psi. I have also seen sign makers foam and is nearly as hard as wood.. Other frame options maybe pultruded fiber glass frames. I have found a few web sites that have stock frame material.
Anyone make a efficient fix pane window?
Patrick T
Replies
patrick:
there's efficient.. and there's cost-effective
1st... i wouldn't use a foam for the frames...
2d .... you haven't really described your south wall..
like some dimensions... is this going to be a single tier.... or a double or triple tier
3d...... always try to avoid reinventing the wheel... and try to use as many time-tested designs as you can
4th.... what is the area like that will be on the north side of all this glazing ?
5th...
do you intend single glazing, double glazing, or triple glazing
so..... a little more background info wold be helpful
Mike,
1) HD Foam was an option due to it's insulation and structure. Foam comes in many forms and can have traits of wood with high insulation
2) Two levels, 30' by 30'' room The entire building is ICF wall. Also not mentioned, part of East wall is also same windows. (Lake view)
3) I guess I am tring to re-invent the wheel. Most pre-made fix windows are just the same as the opening types, just with out hardware.
4) The area inside the window wall is suspended Hambro steel bar joists composite floor. This means steel joists with 4" slab. Also Radiant tube installed, multi zoned.
5) Double or tripple. still tring to balance Solar gain vs. insulation. Were are in Southern Indiana, heating climate
We are building a home of ICF and Hambro floors. The ICF will have an additional 4" of foam attached. Even the roof is concrete, flat for a simi green roof. The windows we are looking at are Fiber Tech tripple pane top of the line. The price for just the wall of windows is $30k +. My background is construction, then later mechanical engineering. With the windows being fixed, I feel that is a major simplification. Glazing being equal between pre-manfactured and site built, it comes down to design, frame and sealing. I feel I could build a window but at what cost?? There are 16 windows approx 4' by 8'.
Thanks for responding
Patrick T
well... the solar industry found out years ago that sticking to standard sizes helps a lot
i'd try to find a glass fabricator that is using Low-iron glass and is fabricating standard sizes in insulated panels,
Indiana is closer to ground zero of glass mfr's than RI is.. so you should have some good fabricators out there
you have to familiarize your self with the techniques of setting insulated glass panels using special rubber setting blocks.... the bearing has to be true for both edges and two-point bearing... if you hobby-horse or if one side ( interior or exterior ) is bearing more than the other, you will have pre-mature seal failure
also, triple glazing is more prone to seal failure than double glazing
a very time tested size is 34" x 76" x 1"....... that will be your best availability and pricing....if you set vertical, you will normally use two setting blocks
if you set horizontal you would normally use 3 setting blocks
even so.....the loss thru the glazing is so high compared to the loss thru the wall sections that the use of foam for trim to gain more insulation becomes moot
if you want to use composites for low maintenance , then i'm all for it.. but watch out for different coefficients of expansion that might play hell with your glazing seals
i have about 40 site built fixed glazing windows on various projects from about 1985 that were all fabricated from lo-iron 34x76x1 double glazed panels with rough sawn cedar frames
NONE has had a seal failure.Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Mike,
Thanks for coming through with the real answers to this series of questions. You've done me another big favor, offering so much useful information and experience on this topic.
Sincerely and Respectfully, Peter
BTW, Happy New Year!
peter .... any closer to building your dream house ?Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
The 2X8 Smith-Mooney wall concept is still lookin' good to me. I'll be making my own fixed windows for the east and south exposures, mainly for the view, so once again, your shared experience is coming through for me.
I expect to go double glazed, placing the glass nearer the outside of each opening, maybe with a thermal break in the framing around the windows and doors. I haven't quite figured that out yet.
The other concept I have to flesh out is some kind of insulated shutter system for the windows. I'm imagining a pair of paneled shutters/doors for each panoramic window, with 2"-4" of the highest rated foam insulation. But maybe bi-folds would seal better.
The view is grand from this home site so there should be plenty of glass on the east side.
Mike,
As far as the standard sizes, I will have arches that can be seen in previous post. The photo is not my wall but my walls are based on that concept. I'm assuming all glass options I may need can be had, low E, kripton filled and such. My focus is on the frames. I know I can build wood frames but I shooting for more efficient frames. Wood is a poor insulator, R-1/inch? Foam R-5/inch. Condensation is often caused by edge effect of the frame, hence all these new window frame materials like fiber glass. Good frames reduce thermal bridging. The frame exterior will be covered by a EFIS type stucco material as will all the house, the interior window janb will be wrapped with drywall to the edge of window frame. Joint would be covered by window stop, PVC? At least that's the concept up to now. Thanks again for your feed back
Patrick T
sounds very ambitious.....
use the forum to float your specific ideas... you'll probably get more advice than you can use... but there will also be some gems
especially if you can post details & sectionsMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
I think that when you get foam dense enough for replacing wood, it will be no-where near R-5 or R-7 per inch as most insulating foam is.Would probably be better than some wood, but keep foremost in mind, that it will also have a high thermal movement that challenges the seals.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Piffin,
I have noticed the expanded foam with low density has lower R-value than the High density extruded foam (for under slabs). Oposite what one would expect.
Diff expansion rates of glass and frames; Fiberglass is best matched with glass. I would prefer to use fiber glass. The arch tops pose a bit of a issue though. Even the main fiber glass window manufacture, segment the arch frames...
Patrick T
Patrick60
The expanding foam is polyurethane. The other is polystyrene.
Ron
You are talking two different kinds of foam,not just two different densities there.I'm sure there is a reason the window makers do things the way they do after a couple generations of learning from their mistakes....back to Mike's comment on re-inventing the wheel.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
My focus is on the frames. I know I can build wood frames but I shooting for more efficient frames.
Not to put words in Mike's mouth (he is far better at it than I) but, I think (just think) his point more has to do with exposed area. After all, we can build walls to R-20, R30 or more, but the best glazing out there is only R3 or so (R4, or 5, max). The effort expended for 1/2 - 1" of frame on 4x8 windows still only nets an assembly around 1/10 the R factor of the entire wall.
Now, sealing the frames, on the other hand, does have a large benefit. And, that's where ad hoc, site-built, and the like can sometimes be less-good in practice. A frame the installers know how to install correctly and air-tight, even at R1.5-2.5 is better than one that does not seal, but might be R3, or R4.
But, I've had to try to go back to clients with walls that were 70% glazed which were not meeting DoE ResCheck minimums, too.Occupational hazard of my occupation not being around (sorry Bubba)
It doesn't sound like you are considering wind load on that wall-O-windows. It would be hard enough to resits with a foam frame in only one unit, but the calculations take a different turn when you fill up a wall with them.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Piffin,
The wall is poured concrete and each window has a concrete post between, 13.25" by 13.25". Each post has 8 pc of vertical rebar. Above the posts the wall continues, creating a 36" tall lintal loaded with steel. Wall is quite stout.
The photo gives you an idea of the design
There are 16 windows approx 4' by 8'
I could tell you how to build low-cost site-built fixed windows, but first I have to tell you that you'll have to open every other window in the house when the sun shines in January.
The glass to mass ratio and proper sun-control overhangs are essential for a livable and functional passive solar house.
You're way into the danger zone. Far too much heat gain and far too much heat loss.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 1/4/2009 8:41 pm ET by Riversong
Riversong,
Slight modification to window area; 14 windows and they don't completely fill the opening. More likely 4 by 6" with arched top. I have seen where the window porportion is ideal at 7%. We are under that. Also, we do have a lot of mass. The entire home has concrete slab floors.
I'm very interested in your sugestions on built in place fixed window construction. I will need to start with good glazing, insulated double or tripple pane with all the coatings and gas filled to meet the solor gain/insulation requirements. What frame materials do you think would be best? As you have seen in my previous posts, I'd like to investigate HD foam or a sandwitch of wood foam to break the thermal bridge.
Patrick T
Edited 1/5/2009 7:20 am ET by Patrick60
patrick... one of my concerns is not building anything that will contribute to premature seal failure of the insulated glassi don't buy any of the suggestions that individual layered glass with removable seals is the way to go...that smacks of the old wooden storm windows of my youth... or the triple track aluminum storms of the '60's & '70's i would like to ensure that the glazing is a one -decision, one- install for the foreseeable futurewe could wind up with glazing that is extremely efficient , but has a high failure rate...
one unit failure every two years would eat up all energy savings of the whole systemMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
MikeSmith,
Agree on both points. The IG needs to be set such that the panel is not under stress to cause seal stress. Also we will go with sealed IG and not layered glass. They would be fogged up in no time. I had Kobe & Kobe windows in my previous home. After 15-20 years, all the IG in the double hungs were replaced due to seal lose. None of the fixed panels ever failed. Your point in a past post of spacers well placed is key.
Patrick T
Just FYI ... if you want the best glass, investigate Heat Mirror glass ... better than triple glazing. One of my all time favorites ... problem has been availability and cost that has grown to be way to high ... but that could be changing again. Many glass companies have no idea what this is. You get a U-value of down around 0.23. It has a low-e coating that can be adjusted for the application. Passive solar, though would use the 'standard' Heat Mirror 88. It is clear in appearance ... looks like any other glass. This is a product by Southwall corporation and is only manuf. in a few locations. I did a sunspace using it back in the 80's when it; I loved it. I've also seen it used in a number of large commercial projects.
Where are you building? What is your lattitude? (You've entered no information on your personal profile). What is the HDD and CDD? What is the solar availability in BTU/sf-day? What U-value are you aiming for and what SHGC?
In the past, I've used standard patio door replacement units (double-glazed lowE argon), as they are readily available and the least expensive option - and they are tempered which is important for any full-height glass.
I do not use frames. Since the ROs are already framed (and any thermal bridging is already take care of in the framing system), I place the IG units in the ROs on 1/2" rubber setting blocks (only 2 per unit, set at 1/4 of width from each corner). I first install outside wooden stops of 3/4 or 5/4 pine, place peel-and-stick butyl glazier's tape on the stop edge facing glass, set the glass on blocks, and then install inside stops of the same thickness as outer with butyl tape on edge facing glass. The inside stop-to-glass joint may be caulked and the outside joints must be caulked with clear silicone. For additional air-sealing, the stops can be applied with a bead of caulk underneath. Inside and outside casing/trim is then nailed to the stops (with reveal).
If the RO is slightly out of plumb, shims can be placed under the setting blocks. This is the simplest and least expensive way of installing site-built fixed glazing, and I've never had a call-back from these.
But, again, I would urge you to make sure that you're not creating a solar-gain nightmare. The 7% ratio should be based on each living space served by the windows (not whole house), the appropriate ratio of thermal mass must be in the direct gain area, with properly-designed overhangs for maximizing winter sun and minimizing summer sun.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Riversong,
We are building in Southern Indiana. The home is an open design except the bd rms. The windows are located in a 2 level open area. All rooms/areas are surounding the open space. I supose I can use return air re-circlation to distribute any excess heat. Or close blinds. As far as U=values, 0.18 is what Fibertech rates their tripple pain, kripton E coated whole units Part of, or most of, the very good rating is the quality Cardinal glazing. The foam filled fiberglass frames are best I know of.
Patrick T
We are building in Southern Indiana. The home is an open design except the bd rms. The windows are located in a 2 level open area. All rooms/areas are surounding the open space. I supose I can use return air re-circlation to distribute any excess heat. Or close blinds. As far as U=values, 0.18 is what Fibertech rates their tripple pain, kripton E coated whole units Part of, or most of, the very good rating is the quality Cardinal glazing. The foam filled fiberglass frames are best I know of.
The high efficiency of the windows will only make matters worse, as they'll reduce heat loss without reducing heat gain (unless they have a very low SHGC and tinted glass).
With a two-storey glass wall, there's probably no way to effectively provide shading. And simply circulating the excess heat will do nothing to buffer it beyond simply sharing the misfortune.
I would strongly suggest doing a heat loss, internal heat gain and insolation/thermal mass analysis before moving from design to construction. It sounds like you might be creating an expensive to operate and uncomfortable house.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
patrick.... i like the arches... have you thoght of decoupling the arches from the windows ?
leave the arches right where they are ... but move the glazing furthur in... so your view remains the same... but your insolation is reduced Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Riversong,
Thanks for sticking with me.
With regards to your concern of over heating, are we still on Winter or Summer over heating? We will have overhangs, even on the upper level windows to reduce/block Summer sun. It's hard for me to imagine having so much heat in January I can't dissipate it via air re-distribution or even opening a window or two. In fact it's kinda nice thought.
Glazing selection is a bit of a trade off. Assuming the sun is blocked in Summer months, I'd think we would want good solar gain and good insulation for Winter.
I don't know the exact mass ratio but all the floors are poured concrete. Part of the walls are ICF and part are poured. Let's say 100 cu yds exposed and another 100 cu yds in the ICF. Some of the mass is coming from an internal poured wall and is opposite side of the room of the wall of windows
Both my wife and I work from our home so we will be able to close blinds/open a window to work with the system. I'd really like to have external insulated shutters to really control both solar and thermal conditions.
But back to frame materials. Sounds like you use wood. I suppose I can use wood too but I'd want to wrap all external with foam to stop any thermal bridging.
Patrick T
But back to frame materials. Sounds like you use wood. I suppose I can use wood too but I'd want to wrap all external with foam to stop any thermal bridging.
Again, I don't build frames - only stops. The thermal break is in the glass units.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Patrick,
Maybe I missed it in a previous post, but when you are talking about building a frame are you talking about physically framing the IG unit prior to installing it in the RO or are you talking about the framing material within the RO?
If you are thinking of framing the IG prior to installing it in the RO (like you would buy a framed, fixed window from a manufacturer), then I would be on the side of rethinking that idea and considering directly glazing the IG unit into the rough opening.
If you are thinking of framing the rough opening with an appropriate structural foam (whatever it may be) rather than using wood for the framing members, then that is a different kettle of fish (whatever that actually means).
As has been mentioned, the energy performance of the IG is by far more important than that of the framing material (air infiltration aside). You have had a number of really excellent suggestions concerning IG performance from clear glass to triple pane, dual LowE coated insulating.
And as has also been mentioned, in a normal home environment an IG with LowE glass will always outperform a clear glass IG unit, no matter what the application no matter where you live. Depending on what you want to achieve, depends what LowE coating you may want to use.
Since you happen to live in Indiana (if I recall correctly), and since you (and others) have already mentioned Cardinal, here is a link that you might find interesting:
http://www.cardinalcorp.com/technology_casestudies/fortwayne.htm
As a bit more background on LowE coatings, there are three basic types - High Solar Heat Gain, Moderate Solar Heat Gain, Low Solar Heat gain.
HSHG coatings are going to be either pyrolytic (hard coat) or single silver sputter (soft coat).
Pyrolitic coatings are primarily tin oxide and are applied to the upper surface of the glass in a process called Chemical Vapor Deposition or CVD. In the CVD process, vapor directed to the hot glass surface reacts to form a ceramic coating while the glass is still semi-molten in the tin bath portion of the float process. Sputter coats are applied to the glass surface as multiple layers of metals and metal oxides in a series of plasma-filled vacuum chambers in a process called Magnetron Sputtering Vacuum Deposition or MSVD (which doesn't mean much in the context of the discussion, but it is fun to say outloud).
Coatings are often referred to generically as LowE, LowE2, LowE3...While LowE is used typically used to indicate either a hardcoat or single-silver softcoat, LowE2 or LowE3 refer to the number of layers of silver in the coating.
LowE2 is a moderate solar gain coating and LowE3 is a low solar gain coating.
Dual or triple silver sputter coats (low solar heat gain products) are generally built to surface #2 of a dual pane IG unit, while a single silver (high solar heat gain) or a pyrolitic coating is often built to surface #3. In a heating dominated climate, the two reasons for placing the LowE coating on the #3 surface of the IGU is to allow for higher solar heat gain in the winter and to block the transference of the heat from inside the home to the outside.High Solar Heat Gain (or HSHG) coatings and Low Solar Heat Gain (or LSHG) coatings all block far - or longwave - infrared energy. This is the range that includes typical household-produced heat. This is also the frequency range of heat that is produced when the sun warms an object – the heat you feel "reflected" from a hot wall or sidewalk on a hot, sunny summer day. While direct solar energy is shortwave IR, the heat released by a sun-warmed object is longwave IR…and hopefully that made sense. A typical hardcoat or single-silver layer softcoat works in this application since all types of LowE coatings block far infrared energy - thus keeping winter heat indoors - but neither coating is particularly effective at blocking shortwave infrared - thus "allowing" solar heat access to the home - winter (good) or summer (bad). Placing a high solar gain coating on surface #3 maximizes the level of solar heat gain thru the IG unit which can be an advantage in winter and can also be a disadvantage in summer. A Low Solar Heat Gain product, on the other hand, is designed to block both near and far infrared energy. It will keep heat - including direct solar gain – from passing thru the window in both summer and winter. These coatings are placed on surface #2 to maximize effectiveness against direct solar gain by blocking solar heat before it can pass into the airspace in the IG unit – and into the home.
And since I have wandered off topic (something I often do), I will stop now.<!----><!----><!---->
oberon, thanks for the discourse.....
just to make sure i understand the lingo..if this is a dual -glazed unit , it has 4 surfaces and the outermost one is #1 working our way to the interior is #2 , #3 & # 4and a triple glazed unit would have 6 surfaces ? from out - to - in, #1 thru #6 , do they always talk in terms of effect ?
HHSG means high heat to the interior ? and thus good for heating climates and LHSG means low gain to the interior, thus good for A/C climates
did i get it ?boy , we sure have come a long way since the '70'sMike Hussein Smith Rhode Island : Design / Build / Repair / Restore
>>> if this is a dual -glazed unit , it has 4 surfaces and the outermost one is #1 working our way to the interior is #2 , #3 & # 4
and a triple glazed unit would have 6 surfaces ? from out - to - in, #1 thru #6 , <<<
Yep, that is correct
>>> do they always talk in terms of effect ? <<<
Not sure I understand the question, but if that relates to the next cuple of questions then I will try to answer there.
>>> HHSG means high heat to the interior ? and thus good for heating climates . and LHSG means low gain to the interior, thus good for A/C climates did i get it ? <<<
HSHG means high solar heat gain, so glass with a HSHG coating transmits direct solar heat thru the window. If the home is designed to make use of solar heat gain then this coating can be very good in a heating climate.
The downside is that HSHG coatings also lose slightly more inside heat to the outside than do low solar gain coatings and HSHG coatings allow direct solar heat gain in the summer as well as in the winter.
But the downsides can be offset by proper design considerations.
LSHG means low solar heat gain. These types of coatings block direct solar heat from passing thru the window. This is the type of coating that you want in a cooling dominated climate.
LSHG and moderate solar heat gain coatings are often considered "all climate" coatings by manufacturers because they tend to be overall more energy efficient that HSHG coatings.
LSG coatings do tend to have lower U-factors and higher winter inside glass temperatures and lower summer inside glass temperatures.
Higher inside glass temperatures in winter and lower inside glass temperatures in summer often directly affect home thermostat settings which has an obvious impact on overall home energy performance.
I think you are simply referring to SHGC .... solar heat gain coeficient. Used to be SC - shading coeficient. When discussing stuff like this, I think it is important to use the common industry standard jargon. I've never in my 30 yrs professional experience heard of LSHG or HSHG used. The SHGC value meets specific testing standards so that when I see a value ... I can use it for comparisons or calculations.
An eave-protected clear double glazing w/ high SHGC (e.g. maybe 0.80 or higher) will gain heat in the winter nicely. In the summer, the eave/shading will effectively reduce the SHGC to maybe to say 0.20 ... that combined with the high sun angle makes a huge dent in the unwanted summer solar gain.
No, I was specifically addressing different types of LowE coatings and their physical effect on the amount of solar gain allowed thru the glass/coating. Some coatings pass solar heat gain and some coatings block solar heat gain. In the glass industry these coatings are referred to as high, moderate, or low solar gain coatings. Some companies refer to them as Low-E versus Mid-E type coatings as well, but that isn't typical industry standard terminolgy.
Windows are specifically addressed in Energy Star standards, for example as "high", "moderate" and "low" solar gain. But Energy Star also uses specific SHGC numbers to describe the differences between them. These are complimentary ideas/terms that describe the same effect from different perspectives. Insulation in a wall can be fiberglass, foam, or cellulose, but performance is described using R values.
While SHGC will list the actual level of solar heat gain thru a window, it also typically includes the effects of frame, sash, and/or grilles on the level of the heat gain - although by definition it doesn't have to do so. Per definition, SHGC can be the glass alone or it can be the entire window system. This is somewhat analogous to using center-of-glass R-value versus entire window U-factor to compare energy performance.
In all cases, a LowE coated window will outperform a clear glass window in terms of overall energy performance. You are correct that a clear glass IG will gain heat very nicely in the winter, but it will also lose substantially more heat than it will gain when the sun isn't shining directly on the glass.
A typical clear glass IG unit built with 1/8" glass and a 1/2" airspace will have a SHGC of .78, while a HSHG LowE unit using a high solar gain coating on surface #3 will have a SHGC of .70. But, the clear glass IG will have a center-of-glass U-factor of .48 while the coated glass IG will have a center-of-glass U-factor of .32. (I used center-of-glass rating because sash/framing material can make a substantial difference in the overall performance and I am specifically comparing glass and not including framing in this example). The coated IG will always have superior energy performance in identical circumstances.
Oberon,
Thank you for jumping in. The main point I was originally posting was how to go about setting a fixed pane window. I agree the frame material is not as critical as the IG unit. But at the same time, why not use the best material for thermal isolation with regards to the frame. The wall is an ICF hybrid with rough concrete window openings at 60" wide. These openings will need infill around the perimeter. Often with ICF construction treated 2x 12s or a combination 2x are used to get the full ICF width.This is what we call the window buck. The window buck has two main purposes; 1) hold back the concrete during the pour and 2) Provide structural surface for attaching windows/doors. I feel it is important to eliminate the thermal bridging of this wood buck. As far as creating a framed opening and installing the IG or setting the IG in a bench built frame is just a matter of what method is best to archive to same result. Having many windows of one type will allow me/my crew to optimize the process. Being ICF wall construction, the wall are quite deep. I want to mount the windows, fixed pane and conventional opening units, in the center of the window opening. This is more of a European method. The exterior is foam of the ICF is covered by an EFIS system and the interior is drywall. Both interior and exteriors wrap around without bulky wood jamb/trim. So as you maybe able to imagine, very little of a frame is even seen.
I do need to read up and/or take advisement from experienced glazing experts like yourself to determine the best glazing for our local condition and orientation of this wall.
Patrick T
geesh.... gimme a break<<<<Thank you for jumping in. The main point I was originally posting was how to go about setting a fixed pane window. I agree the frame material is not as critical as the IG unit. But at the same time, why not use the best material for thermal isolation with regards to the frame. The wall is an ICF hybrid with rough concrete window openings at 60" wide. These openings will need infill around the perimeter. Often with ICF construction treated 2x 12s or a combination 2x are used to get the full ICF width.This is what we call the window buck. The window buck has two main purposes; 1) hold back the concrete during the pour and 2) Provide structural surface for attaching windows/doors. I feel it is important to eliminate the thermal bridging of this wood buck. As far as creating a framed opening and installing the IG or setting the IG in a bench built frame is just a matter of what method is best to archive to same result. Having many windows of one type will allow me/my crew to optimize the process. Being ICF wall construction, the wall are quite deep. I want to mount the windows, fixed pane and conventional opening units, in the center of the window opening. This is more of a European method. The exterior is foam of the ICF is covered by an EFIS system and the interior is drywall. Both interior and exteriors wrap around without bulky wood jamb/trim. So as you maybe able to imagine, very little of a frame is even seen.I do need to read up and/or take advisement from experienced glazing experts like yourself to determine the best glazing for our local condition and orientation of this wall.>>>>>Mike Hussein Smith Rhode Island : Design / Build / Repair / Restore
Edited 1/9/2009 8:00 pm ET by MikeSmith
MikeSmith,
I assume there was something in my post that didn't sit well with you. What was it?
Patrick T
I believe that what Mike meant when he said gimme a break was a "line break" or a "carriage return" since he then proceeded to reformat your post.
In print large blocks of text usually work, because there is enough place separating the lines of text . On a computer screen, to many people, large blocks of solid text unbroken by white space are extremely hard to read.
Sticking a blank line in every now and then helps with the readability.
Edited 1/10/2009 9:44 am ET by rvieceli
Simply, you want to replace the wood window bucks with something more efficient. Everything beyond that is negotiable.
Although this is outside of my area of experience, I would probably be primarily concerned about the structural integrity of using foam to mount the glass.
IG units at the size that you are going to be installing are heavy. They also are going to be subjected to some pretty substantial winds.
Since the walls are thicker and you are planning to mount the glass in the middle of the wall, have you considered using 2x4 (for example) for middle-of-the-wall window bucks with applied stops (which could be a structural foam(?)) and then using foam insulation to both the interior and exterior of the center wood?
Oberon,
""Since the walls are thicker and you are planning to mount the glass in the middle of the wall, have you considered using 2x4 (for example) for middle-of-the-wall window bucks with applied stops (which could be a structural foam(?)) and then using foam insulation to both the interior and exterior of the center wood?""
Your statement above is what I'm thinking would work. As long as the IG is seperated from the wood buck and the stop is thermally isolating, it should work.
Thanks again,
Patrick T
You would want to isolate the IG unit from the wood buck in any case (setting blocks) since a tight IG (edges) is potentially a failed IG due to different coefficients of expansion and all that other cool physics stuff). Thermal isolation in that case is bonus.
A deeper reglet will isolate the spacer from the stops and since glass is a lousy conductor of heat there will be thermal advantages as well.
There are European companies that have very deep glazing reglets and they are seeing some very nice energy numbers even using aluminum spacers and thermally-broken aluinum frames.
Foam glazing tape on the stops will also provide some level of thermal isolation from the wood stops, but the depth of the glazing reglet will affect thermal performance at the edge even more.
Edited 1/10/2009 12:06 pm ET by Oberon
I don't entirely agree re: the shading and window efficiency. I was under the impression the OP had checked the geometry of his overhand/eave and checked for summer shading and it was good ... is that right Patrick?
If it is two story, that doesn't mean shading is out of the question. There are still options available. If this is two story unprotected (in the summer) glass, then, I agree; it will be overheating in the summer (i.e. the house will trap excess heat). As for the winter, clear glass is the only way to go IMO. Otherwise may as well not be doing passive solar. If there is excess heat in the winter, it's easy to control. I'm guessing that usually sunny days in winter in Indiana are COLD, so it shouldn't be much of an issue.
I missed the post stating he had a two story window configuration (I know he showed a sample picture, but did he say it was to be a fully two story window?). It still doesn't preclude a design w/ some shading, though.
I have a similar such condition.. In the winter the leaves fall off the trees which shade the southern exposure So in the summer I'm in shade in the winter I have direct sunlite..
Create your own mini climate!
As for the winter, clear glass is the only way to go IMO. Otherwise may as well not be doing passive solar.
Have you tested that theory?
In a cold climate with moderate solar availability, a high solar heat gain lowE double-glazed window on the south tends to come out ahead of any other option, particularly clear glass since the heat loss is excessive. Even a moderate SHC lowE window (like Pella Proline) comes out ahead of clear IG.
For instance, for the superinsulated passive-solar house I built here in north central VT(8500 HDD, ~900 BTU/SF-day solar), I used moderate SHGC lowE² Pella windows on all sides.
If I had used clear IG except on the north, the annual heat load would have increased 7%. With a high solar heat gain LowE window on E,W & S, I could have decreased the annual heat load by 11%.
The right balance between solar heat gain and insulative quality is dependent on local climate. You cannot make any blanket rule about passive solar glazing.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 1/8/2009 8:29 pm ET by Riversong
Yes, I have tested the theory. I think you are misunderstanding my discussion. Clear insulated glass ... meaning non tinted, non mirrored glass. Low-e (IMO) is the standard minimum glass. I used Heat Mirror glass in a passive solar sunspace very effectively. I thought it worked great. Clear glass, low-e coating on a milar film. High SHGC, low U-value (around 0.23). It was clear glass. I've also used (in the same house) tinted AND mirrored Heat Mirror glass on the west orientation to control strong west summer sun ... it had a low SHGC ... down around maybe 0.15.
For passive solar to be effective, you have to use clear (i.e. untinted, not mirrored) glazing. Net heat gaing in winter. Protected in summer, it won't be a problem (i.e. it won't 'trap' heat). I think you simply misunderstood what I was saying.
Clear insulated glass ... meaning non tinted, non mirrored glass.
I think you simply misunderstood what I was saying.
Yes I did, because you're not using glass industry standard language.
Clear glass means uncoated glass. LowE glass is not called clear glass.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Uh ... that's not what I've ever thought. Clear glass is just that ... clear whether coated w/ a low-e coating or not. I've never heard of low-e as being referred to as tinted and I've ordered clear low-e many times. I just put some in my house ... I also ordered tinted and mirrored low-e. I think maybe it must be some local symantics that is the misunderstanding.
Clear glass is just that ... clear whether coated w/ a low-e coating or not. I've never heard of low-e as being referred to as tinted
I didn't say "tinted". Tinted glass has a visible color. LowE used to have a visible color, but that problem has been corrected.
I think maybe it must be some local symantics that is the misunderstanding.
If you look at any glass manufacturer's or window manufacturer's catalog, it will list "clear glass" as having no coatings, lowE or tints or mirrors.
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
You might want to investigate sliding glass door replacement panels. there are some aluminum tracks built to accept this thickness, and you cut and miter them, along with their sealing gaskets.
View Image
I made a ~5x7' sklight like this above our master shower, and it's been fine for fifteen years. It was under $200 total.
Forrest
Edited 1/3/2009 11:08 am ET by McDesign
My 2 cents
If you are going to stay in your house over 20 years do not use sealed units.
I know, Iknow, everybody will say that 'the new sealed units wont leak like 'old' ones did, etc, etc.' - I'll believe that in 30 years if I live that long!
I'd build fixed exterior with PT wood frames, interior panes in sealed frames that allow removal to clean every 5 years or so - what I did after $20,000 of sealed units fogged after 20 to 35 years. Used typical door weatherstripping for sealing the interior panes.
None of the sealed units (including patio door) in our 32-year-old house have leaked, other than two that I know for a fact were mechanically damaged. (In one case a piece of falling lumber hit one; in the other case the snowblower threw a chunk of ice into it.)
The mark of the immature man is that he wants to die nobly for a cause, while the mark of a mature man is that he wants to live humbly for one. --Wilhelm Stekel
Don't forget an eave/overhang for summer sun protection!! You will hate yourself if you leave your glass unprotected!! Or you will spend BIG bucks buying all kinds of make do shades, blinds, and what have you to try and correct a mistake that is easily handled prior to construction. What is the height of your windows?
Why not simply stop the glass panes in place? Why buy a frame? Frames take up space/area. There is a time an place for everything and only you know the details of the result you are trying to achieve. Stopping in glass is the handyman's way to a fixed frame that tends to be inexpensive (albeit, it can be labor intensive). If final finish is not necessarily 'fine', consider developing a simple stopped in detail. You might even incorporate into the concrete itself (if not already poured).
Use low-e glass, too.
Clewless1,
You are correct, window shading is key for two reasons, Summer shading and window protection. Our over all wall depth will be approx 17" and the window will be mounted mid way. A small overhang running the entire length of the wall will be designed for optimum sun shading during Summer months.
Your second paragraph hits the nail on the head. I don't want to buy frames, I want to build in place. The opening is 5' wide so I have plenty of room for a built in place stop. Forming a stop ledge in the concrete is complex and is not required. The concrete needs to be thermally isolated in any case. Because of the arch top, I think it would be best to build the frame in the shop. Then using a mock pc of glass, plywood, mount the frame. The mock pane would hold the frame is the exact placement. The frame profile could be as simple as a standard door jamb
Patrick T
Call the folks at Resource Conservation Technology in Baltimore. They make specialized gaskets and weatherstripping for fixed pane windows as well as movable windows. I suggest you talk with them about what you want to do and what they suggest, and go from there.
http://www.conservationtechnology.com/building_glazing.html
I also suggest you send a message to "Oberon" who posts here -- he knows as much or more about glass and the related technology than anyone else here, and he will tell you where the limits of his knowledge ends, such as whether he has any experience with customized built in place window frames.
Billy
... like a standard door jamb ... yes that's the idea. But your concrete structure doesn't have a thermal break, does it?
How tall are your windows? How deep is your eave (from the window surface)? How high from the window does the eave start (i.e. where does the eave connect to the house above the window ... 1 ft? 3 ft? 2"?).
I built and ICF house in Cold Canada in 97. We used All Weather Windows, Edmonton, Alberta. We got the fiberglass frames and -37 C today no frost no fuss no rot. I sized my overhangs and glad I drew it out in the cross section and glad I did. Full sun none and none in the summer.
I admire your spunk but sometimes.... Maybe with the differance of the US/Can $ you can get them cheaper that I did. I to live on a lake, Pasqua Lake SK and perfect south orientation. Use google earth and visit!I ordered the frame with a 3/4 inch drywall return and build Birch ply boxes to fit in the return and form part of the wall differance to finished inside. Foot deep extention Jambs if you may. and I brought the sills out 3 inches to form a seat or plant stand. The cats love them.
Now I wished what view would change to a nice lovely lake instead of the frozen, snow covered, wind driven hell it has been the last couple weeks.
Clewless,
ICF is a system of foam/concrete/foam. Good thermal breaks. Overhangs will be added later to optimize solor gain/minimize solar gain.
Patrick T
How will you prove that your site-built windows conform to construction code requirements for wind loading and other factors?Jeff
Anyone make a efficient fix pane window?
Any South facing window allows in much sunlight.... As the sun rises and falls, the arc of sunlight lets in all those fading rays. Your drapes, upholstery, carpeting will fade something awful, especially any dark colors or around furniture that blocks the light below them, leaving unfaded blotches of color when you rearrange the living space behind those large windows.
For true efficiency, you might be better-off buying Low-E double or triple pane windows....
Bill
Billjustbill,
Yes sun does a job on fading objects. This is an open atrium with stained concrete floors. Good to go.
We will buy Low E double or tripple glazing, the point is site built frames.
Patrick T
I'm always on a learning curve. I was wondering how will you keep out the moisture between the glass layers?
Had a little jacka$$ live down the road that used a small rock on a double pane picture window. Before I could get the insurance to pay and order another, moisture got between the glass... Talked to the boy's dad, except for hearing about his boasting at his high school, neither took responsibility....
Bill
I made several fixed windows and there was a massive cost savings in doing it myself.. You have to shop for glass though!
and not very much before you need the windows either, another words this is an area where you take your best shot and when push comes to shove there will be a differance between your calculations and real world costs.
I was greatly surprised that my local glass guy wound up getting me a better deal than all the big "discount" places could.
I made my frames out of black walnut because it was cheap (I know, but I did get a great deal) decay resistant and matched the exterior trim of my house..
I went with triple glaze,, two clear glass and one stained glass. I knocked out the frames really quickly even though they were round and the glass was flat (another words the windows went into a round tower)
If you are going to use foam and it's affordable that's fine but you'd better figure out how to clad it somehow. Foam won't stand up well to UV light. If you wind up going with wood buy wood from a sawmill and get it cut to your size requirements.. Buy the glass then make the frames and then make the rough opening for the windows..
Frenchy,
I have not tried the local glass shop. I was thinking I'd have to go to Cardinal, the IG supplier for most/many window manufactures. Guess I better give the local guys a try. Any foam I'd use would be completely covered by drywall for inside and EFIS coating outside.
Walnut is one of my favorite woods. I've seen old barn window frames 150 years old and you could still widdle a bit of the old gray and see the nice dark walnut. Easy to work too.
Glad to hear you saved big bucks doing it yourself. That is my goal...I figure by having so many to make, I can get a production line going.
Patrick T
Edited 1/7/2009 7:04 pm ET by Patrick60
Glass tends to vary considerably in price. I was able to use glass from broken store windows that had been a victim of a pellet gun. That glass is much thicker than normal houshold glass and thus less likely to break.