Glass or plastic

[steve-norrell]

I want to build a storm window for the sidelights on the sides of our front door. The door itself has a Larson storm door.

The sidelight is about 79" high and 14" wide. I was planning to use clear 3/16" Lexan because of its clarity and resistance to breakage, but the spouse thinks we need to use tempered glass because the Lexan will be affect by UV light even though the slidelight is under a covered entrance.

Any comments and suggestions are welcome.

Thanks, Steve

[whitecobra]

Spouse is most likely right
The Lexan will "change color" over time
Atleast down here in Florida they do

We have Lexan Skylights throughout our home and I HATE them
They DO get "funky" with age and UV exposure

Since they are a very "bubble shape" I can't even remove them and replace with glass

Dr D

[steve-norrell]

Spouse is most likely right
The Lexan will "change color" over time
Atleast down here in Florida they do

We have Lexan Skylights throughout our home and I HATE them
They DO get "funky" with age and UV exposure

Since they are a very "bubble shape" I can't even remove them and replace with glass

Dr D

Dr. D: Interesting. We also have plastic skylights, three of which have been in for more than 15 years. There is no discoloring, even with the long hours of summer daylight. At worst, there may be very slight fogging -- judging by the view of nearby trees through the skylights -- not enough to impede light or vision.

Further, the sidelight windows by the front door will receive only minimal exposure to direct sunlight as they are in a covered entranceway.

A local plastics dealer recommended the Lexan over other plastics.

Looking for more input. Thanks, Steve

[jlm]

Lexan comes in multiple formulations. "Lexan XL" is the stuff you want - it's got a UV-filter coating (actually a layer of material extruded along with the Lexan so it doesn't scratch off like a sprayed-on coating would), and is warranteed for something like 10 or 15 years against yellowing (make sure you install the coated side facing out). Since it's in a protected area not likely to receive lots of direct sunlight, I'd imagine you won't have to worry about yellowing for a long, long time with the XL.

Plain ol' Lexan, though, will yellow after prolonged UV exposure, as will almost all non-treated clear plastics.

[cabinetman]

Here's my .02 cents. The Lexan XL is their designation for their UV protected sheet. Actually a better GE product for windows and glazing is MR10 which has UV resistance and abrasion resistance, about equal to glass. The MR10 is widely used in commercial and public buildings because of its UV and abrasion resistant qualities.

Just a note that "Lexan" is GE's brand of polycarbonate. The name/term has come to be used as general terminology for polycarbonate.
.
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[steve-norrell]

Jim, cabinetman, Dr. D;

Thanks for the information. I did not specifically ask if the Lexan recommended by the plastics guy was UV protected but will do so before I buy.

An interesting aside - - this morning when I went out to get the paper, I found it IN the bay of the front door sidelight. An argument for Lexan over glass.

Thanks again for the advice. Regards, Steve

[atgcpaul]

I'm assuming the plastic is cheaper than the glass and this is why you're asking.
Would adding another layer of protection to the plastic work? Like one of those
UV films for windows? If the price starts to equalize, at least the plastic ones
are a lot lighter.


Paul

[steve-norrell]

I'm assuming the plastic is cheaper than the glass and this is why you're asking.
Would adding another layer of protection to the plastic work? Like one of those
UV films for windows? If the price starts to equalize, at least the plastic ones
are a lot lighter.

Paul

Paul:
I have not looked into either plain glass or tempered glass. I assume that the Lexan will be less expensive (especially when compared to tempered glass) but I do not know that for a fact.

My main reason for thinking of Lexan is that I am interested in the breakage resistance of the plastic. My experience (admittedly limited) with the paste-on films is that they are a PITA to apply and do not hold up very well. I understand that the UV protection for Lexon, especially Lexon MR10, is either bonded to the surface or incorporated into the polymer and will last about as long as the plastic itself.

Thanks for the input. Regards, Steve

[whitecobra]

Dr. D: Interesting. We also have plastic skylights, three of which have been in for more than 15 years. There is no discoloring, even with the long hours of summer daylight. At worst, there may be very slight fogging -- judging by the view of nearby trees through the skylights -- not enough to impede light or vision.

Further, the sidelight windows by the front door will receive only minimal exposure to direct sunlight as they are in a covered entranceway.

A local plastics dealer recommended the Lexan over other plastics.

Looking for more input. Thanks, Steve

I guess the difference is that we get hotter then **** sun 350+ days a year
Temps in and above 100 never below 35 or 38. I guess a bit different then up your beautiful part of the country

Not actually sure but I can tell you that these pups are not great
Many guys shift to smoke over clear or opaque or to FLAT skylights for that exact reason

The problem with the flat ones is they leak so it is ****ed if you do and ****ed if you don't

If I had it to do all over the roof would be the roof and the windows would be the windows and I wouldn't be trying to put windows on the freaking roof

Need to look into the XL stuff for replacements

Dr D

[steve-norrell]

Interestinger and interestinger . . . .

Actually, the engineers strongly recommend against skylights here because of the heat loss and ice damming that occurs 'downhill' from them. The LOML however insisted and we are paying the cost - - heat tape below the skylights and in the raingutters. Lots of other folks have them because the enhanced lighting becomes important in the winter.

Also, we found that the clear plastic sheets sold to reduce heat loss on windows works wonders on skylights. Apply the plastic sheet (across the opening in the ceiling) according to instructions and lightly tighten it with a hair dryer. This creates a dead air space between the ceiling and the inner surface of the skylight. The flow of cold air under the skylight is dramatically reduced in winter, as is the rate at which snow melts on the outer surfaces.

We do have a minor problem with green house effects during the long daylight hours of summer. While it is noticably warmer under the sklylights when the sun shines directly on them. it is not enough of a problem to do anything about.

Regards, Steve