By on April 9, 2012

Carglass is one of the most lucrative sectors of the sometimes obscenely lucrative auto service business. Their eyes glaze over when purveyors of pristine panes talk about a new trend in car design: Glass roofs.

Lincoln’s new MKZ shines new light on carmakers’ attempts to turn cars into true glasshouses. From a glass roofed Mustang to an englassed Mercedes Shooting Brake, more and more cars look like 21st century popemobiles, to the excitement of the glass trade.

“We are seeing larger windows and sunroofs,” rejoices Jeff Olive, training manager at Glasspro in Mt. Pleasant, S.C. “Glass roofs are here to stay,” says Bob Beranek, president of Auto Glass Consultants in Sun Prairie, Wis., both cited in GlassBytes, the TTAC of the carglass trade.

Whereas stationary glass roofs are fairly quick to replace, retractable roofs promise to sell many billable hours. Says Beraneck:

“The much harder install comes when the entire roof module needs replacing. This is usually when the retractable regulator is defective. Plan on all day to replace one of these.”

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50 Comments on “Glass Roofs Make Mechanics’ Eyes Glaze Over...”


  • avatar
    tced2

    I guess if the automakers insist upon gun-slit side windows then we are going to have to settle for expensive to fix glass roofs.

    Years ago, my father had a GM Olds station wagon with the clamshell retracting tailgate – the glass retracted into the roof and the tailgate dropped into the floor. The dealer advised my father that the repairs for a rear-end collision could be costly to the unusual tailgate mechanisms.

    I wonder about the crash aspects of a glass roof. On rollover the glass roof protects me just as well as steel?

    • 0 avatar
      Frownsworth

      Stupid gun-slit windows. I never did understand their rationale for doing that. It makes you feel like you are entrenched in a WWII fox hole.

    • 0 avatar
      Robert.Walter

      When my sister backed our then 6 year old ’72 Chevy Kingswood wgn (dad bought new from Roger Penske no less!) into a phone pole (dead center! Don’t ask), dad didnt see the sense in repairing the 3rd kids car) the door never went down again until I bought some parts a few years later in a scrap yard and replaced them myself.

  • avatar
    roadscholar

    I still don’t understand fixed glass roofs that add a ton of weight as far away as possible from the center of gravity but then again, I’m a car enthusiast who likes cars that handle.

    • 0 avatar
      Mark MacInnis

      Glass is more dense than steel for a roof application?

      I was thinking the other way…two reasons the car makers are going this way…the “OOOOHhhhhh” factor, and the lighter weight….

      Anyone know which of us is correct? Which is lighter, steel or glass for a roof application?

      • 0 avatar
        Crabspirits

        Glass is always heavier, especially if you have mechs for it and steel reinforcement to support it. The alternative is usually just a section of 16ga sheetmetal, which weighs almost nothing.

        I would get one anyway on a new car. They are already bloated out of control. Declining the glass roof isn’t going to give you a miata. At least I won’t feel like I’m sitting in a pillbox with these out of control beltlines.

      • 0 avatar
        Ron

        Sheet steel used for a car roof is no more than 24 gauge (0.28 inches), which weighs 1.156 lbs/sq ft. Even excluding framing, glass is more than twice as heavy. For example, 0.25 thick polished plate glass is 3.28 lbs/sq ft.

      • 0 avatar
        chuckrs

        So getting a glass roof sounds like a double win – heavier and weaker. Oh and more expensive too.

      • 0 avatar
        L'avventura

        I guess, we just need to wait for transparent aluminium to get cheap enough for automotive applications….

        http://blog.makezine.com/2012/01/17/transparent-aluminum/

      • 0 avatar
        Geekcarlover

        Also take into account the additional frame reinforcements needed with a large glass roof. If it flexes very much you risk ruining the seals or cracking the glass.
        Many clear polymers are almost as scratch resistant as glass. They’ve been used in the eyeglass business for years. Just remember ALMOST does not equal SAME AS.

      • 0 avatar
        Ron

        I slipped a digit in my calculation of steel thickness. Nevertheless, the conclusion remains the same — glass is more than twice as heavy as steel for the same thickness. Furthermore, glass isn’t as strong as steel, even when tempered, which means that it has to be thicker, and thus, heavier, when used in a roof.

    • 0 avatar
      tekdemon

      It doesn’t have to be actual glass, the Prius uses a lightweight polymer for its panoramic roof and my guess is that its not going to be the only car that does so.

  • avatar
    Rday

    My wife and I have been having skin cancer problems for years. I can’t see where these glass roofs are going to be good for ‘skin’. Unless the glass is treated to reduce UV, the glass roofs seem like something we don’t need and it will cause problems.

    • 0 avatar
      Crabspirits

      Next time you are in a car, look at the emblem in the corner of any piece of glass. Almost all of it is UV treated.

      • 0 avatar
        Frownsworth

        Yep, almost all household and automotive glass blocks nearly all of the UV spectrum, except for the weakest part just outside of violet.

        Not that I care for glass roofs.

    • 0 avatar
      tedward

      all of them that I’ve seen also have full sun shades, most of which also allow breeze through at speed. I probably wouldn’t spec one to buy, but when i drive them its sunroof open/sun shade closed. I have to admit it’s a pretty cool feature, with far more benefit to the ambiance of the car than any single center stack option.

  • avatar
    Zackman

    Glass roofs? Another good reason to wear a hat…I do!

    I hope prospective buyers realize what they’re getting into with all the glass aside from a moonroof that is being built into certain car models. I shy away from this. My Impala doesn’t have a moonroof and I didn’t want one. Our CR-V does. Our MX5? Well…that’s another animal altogether.

  • avatar
    grzydj

    It’s all lucrative, very much so. Most shops bill out for a replacement roof panel after hail damage and end up doing a paintless dent repair on the panel and sending the panel back and still billing the customer for it.

    I’m not saying all shops do that, just most of them.

    As for the glass, there’s already lots of cheap, terrible quality aftermarket Chinese and Taiwanese made glass that I’m sure will make its way into expensive glass roofed SUVs and the like.

    I’ve seen a retractable Subaru Forester with a soccer dome sized glass panel get replaced before and I can assure you that it is a pretty significant job. It requires removing all the interior trim panels and fabric. I’m sure zee Germans have found a more complicated way of engineering a retractable sunroof, so maybe those would get billed out for more hours.

    • 0 avatar
      Zackman

      “I’m sure zee Germans have found a more complicated way of engineering a retractable sunroof…”

      Have you seen a VW Eos retractable top WITH a sunroof lately? Now THAT’S complicated. Complicated enough that I’ll never own one, though wifey and I love them.

      • 0 avatar
        grzydj

        Worked on a hand cranked ’87 VW Scirocco sunroof and thought that was overly complicated, can’t imagine how much more complicated it could be than that. I think they built the car around the sunroof assembly, the same way Toyota built the first gen 4Runner around the heater core.

      • 0 avatar
        espressoBMW

        My wife really likes the Eos also so we’ve been looking for the VR6 priced just right. The roof is pretty complicated and cool but doesn’t worry me too much. Nobody in the forums are talking about problems anyway. And at least they are hydraulic instead of electrical.

  • avatar
    PintoFan

    So? All auto repair is lucrative, if you have the knowledge and know how to run a business. As long as automobiles continue to be complex machines, certain components of which can only be repaired with specialist knowledge, then this will remain true.

    I’m pretty sure the reason this piece was written was to take a potshot at the MKZ. I was guessing that this was coming, after Baruth praised it highly in the New York Auto Show video. Lord knows that a good deed can’t go unpunished, especially not when it relates to the U.S. auto industry.

  • avatar
    Crabspirits

    I’m going to call BS on the “OMG risk” of these sunroofs. Have you ever tried to break a piece of tempered glass? Not that easy. Anything that will shatter a sunroof would be an extensive sheetmetal repair for the alternative. Most of these panes bolt on to whatever retracts are up there, just like a piece of door glass. There should be no reason to replace a whole module. Likewise for the regulators. I should think all manufactures have figured out how to make a power sunroof work for years at this point.

  • avatar
    morbo

    My 300C has the panaoramic dual pane glass roof. I’m sure it will leak like a mo’ somewhere between Year8 – Year12. I know it makes it top heavy relative to it’s steel roof siblings. I know it added undue cost when I bought. I know that it’s nearly useless in most situations, as the sun is either glaring in my eyes or burning my skin.

    But on the right twisty road in cool but not cold weather, HEMI purring as the sun and wind caress the cabin,

    Greatest. Ride. Evar.

    Plus women seem to love it.

  • avatar
    getacargetacheck

    Another stupid fad designed to separate people from their money. Can’t wait to hear about all the MKZ owners online crying about all the rattles in their new “luxury” car. The forums will be ablaze with these crybabies just before Ford gives up and closes Lincoln.

  • avatar
    newfdawg

    This is simply another stupid styling gimmick, how about doing something useful like getting rid of those gunslit windows and giving
    drivers some real windows they can actually look out of?

  • avatar
    Junebug

    My beautiful, lovely and wonderful wife just loves sunroofs and insists that every vehicle she owns has one. Why? beats the hell outta me, she never opens the damn thing and only slides the curtain thing back at night. Waste of money, but NEVER argue with a woman!

    • 0 avatar
      Zackman

      I could almost quote you 100%. Wifey LOVES her moon- er- sun – whatever- roof and does use it during the day. Me? I close the thing when I drive it during daytime.

      I don’t understand the attraction of these. I’d rather get an option for vent windows like VW and Ford offered for a time in the ’80’s…something…USEFUL!

    • 0 avatar
      Dave W

      Neither my wife nor I particularly like or dislike sunroofs, but our previous car had one because in the bizzaro world of car options the only way Hyundai (and I think Subaru) would sell you ABS at that time was with a sunroof.

  • avatar
    Felix Hoenikker

    The glass roof resembles the vinyl roof fad of the 70s. And just like the old vinyl roofs, I’m sure it requires frequent cleaning to keep it looking decent.
    So you pay extra for the initial looks and then pay more for maintenance (extra time or money to clean the roof) relative to a steel roof.
    Not a feature I’m looking for.

  • avatar
    Educator(of teachers)Dan

    I sure stay out of Death Valley with that type of roof. Wonder what some of these states that are restrictive about the amount of tint on a window would say about me going “LIMO BLACK” on a glass roof?

    Oops wait I just gave the politicians a new idea… Regulation for regulation’s sake.

  • avatar
    mistercopacetic

    Last week I put about 500 miles on a borrowed Tiguan with the panormaic sunroof. My current daily driver doesn’t have a sunroof, so there were two things I immediately noticed: 1) when the side windows are down, there is a tremendous amount of turbulence, even at low speed. So, if you want some fresh air, the only option is either close all the windows and run the A/C, or crack the sunroof. I’ve noticed this in other new cars as well. 2) When the sunroof is wide open you can hear birds chirping in trees overhead. I’ll admit that was nice after long days at the office.

    All other criticisms are valid though, I’m sure the cost of repair is sky high due to the size and complexity of the roof panel, and of course it adds weight exactly where you don’t want it. The sunroof cover is also not completely opaque, more like a mesh screen, so the sun really bakes the seats (black V-tex), even when outside temp is around 60F. Last but not least, I don’t want to know what might happen when six feet of glass–right above my head–breaks during an accident.

  • avatar
    Herm

    The panoramic roof does not have to be retractable or made of glass.. plastic is fine but you will have to buff it out every 5 years or so.

    Its time for ALL windows in a car to be made of plastic.

  • avatar
    millmech

    This was an option on the Citroên-

    This is a YouTube clip from the Tenth Victim with an ID/DS19 with the optional clear roof; address may not show in this venue.

  • avatar
    fredtal

    Ron stated:
    Sheet steel used for a car roof is no more than 24 gauge (0.28 inches)

    24 gauges sheet steel is 0.0149″ thick, I doubt there is any steel in any car that is 1/4″ thick.

  • avatar
    grzydj

    Just found that the seal around my sunroof on my ’96 Subaru Legacy is leaking after running it through the car wash on my lunch break. Great timing this thread is. :)

    Turns out a loosened a seal around the glass scraping ice off the sunroof over the winter. Whoops.

    There has always been a broken pin on one of the tracks, so I’ve never been able to use the sunroof anyway, time to seal it up for good.

  • avatar
    indi500fan

    I looked long and hard to find my current Caddy SRX that doesn’t have the retractable glass roof.

    In addition to the squeak, rattle, and service issues with the retractor mechanisms, Lord help you if the sucker breaks. The insurance company says it’s a factory defect in the glass and the vehicle mfgr says it’s due to a road hazard. Try proving either case when the roof is now a couple bucketfulls of pebble sized glass fragments. (Don’t ask me how I know this, LOL)

  • avatar
    Geekcarlover

    Ford, and I think Olds, tried this back in the 50’s. But they used Plexiglas. Not too many people went for it. Also when I think of “extra glass” I think of AMC Pacers. Here in Florida you could bake a cake in one of those beasties.

  • avatar
    FPF422

    About the weight, some brands (including Mercedes Benz)are using Spallshield from DuPont
    DuPontTM Spallshield is a three-layer composite
    structure of PVB/PET/hardcoat. The hardcoat is
    highly durable, chemically resistant and virtually
    indistinguishable to glass allowing it to replace one
    of the lites of glass in a glazing structure. This
    dramatically reduces the final weight of the glazing.
    http://www2.dupont.com/SafetyGlass/en_US/assets/pdfs/spallshiel
    d_brochure.pdf

  • avatar
    CRConrad

    Uh, about that whole “making someone’s eyes glaze over” thing… “I don’t think that expression means what you think it means”, to (almost) quote _Princess Bride_.

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