Question for ordering door glass

[Roger Marty]

Newbie making an exterior door (and so many experts on this forum!).

I need to order some double-paned glass. The Freud cope-and-stick router bits create a slot of 5/8" (of course I routed one side off to actually insert the glass). I was thinking of ordering 5/8" glass and then creating trim with the same bits. But I've never actually done this before, and see that some glazing tape has a thickness of 1/16".

Should I order 1/2" glass instead to account for glazing tape? Or does the glazing tape not really add much thickness in practice?


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[Tom M King]

How will the glass be replaced when it needs to be?

[John TenEyck]

Yes, you need to account for the thickness of the tape. I'm not a pro, but when I've made exterior doors with glass panels I adjusted the thickness of the trim molding after the panel was set against the tape.to bring it flush with the stile/rail.

John

[Roger Marty]

One side is open. I'll make marching trim to hold in the glass.

[Tom M King]

I prime the inside of the opening with oil based primer. Glass is bedded in enough latex caulking to squeeze out all around. leaving no gap anywhere. It's easily trimmed back to nothing the next day where it matters. Paint, or varnish laps over the outside thin joint over the caulking, and bonds to the glass. In 30 or 40 years, when the glass needs to be replaced, it will still be sealed all around, but the glass can still be removed, and made ready for the next one pretty easily.

I know this thread is about insulated glass, but if anyone does similar with single paned glass, the interior finish on the door, or window, needs to be an exterior paint, or finish, because solid water will condense on the single pane glass on the inside at some point, and run down, ruining interior paint.

So far, none of the glass I've installed like this, since the '80's, has needed to be replaced, or glazing failed. Some I did in the '70's, using more standard methods have.

[Lee Schierer]

Glass in doors is supposed to be tempered glass for safety reasons.

[Peter Kelly]

I'd order an 1/2" insulated glass unit which should be seated in 1/4" thick weatherstrip that will compress to 1/8" when you add the stop to the back.

I don't think most glass manufacturers will ship an IGU without tempering. Would probably get broken during shipment otherwise.

[Alex Zeller]

What sort of climate do you live in? The unit will need to be made of safety glass. It'll be either tempered, laminated, or glass with wire inside but for 1/2" think it'll have to be made out of two sheets of 1/8" tempered glass. That leaves only a 1/4" gap between the two of them, not a lot of thermal insulating value. Just like insulation the thicker the better. I wouldn't use the glazing tape. Normally it's a foam strip and it doesn't seal perfectly in the corners. You'd be much better off laying a thin bead of caulk and setting the glass into it. Of course my opinions are bias for where I live. If in the south west where rain is rare and heating is not as much of an issue you can get away with less.

[Roger Marty]

What sort of climate do you live in? The unit will need to be made of safety glass. It'll be either tempered, laminated, or glass with wire inside but for 1/2" think it'll have to be made out of two sheets of 1/8" tempered glass. That leaves only a 1/4" gap between the two of them, not a lot of thermal insulating value. Just like insulation the thicker the better. I wouldn't use the glazing tape. Normally it's a foam strip and it doesn't seal perfectly in the corners. You'd be much better off laying a thin bead of caulk and setting the glass into it. Of course my opinions are bias for where I live. If in the south west where rain is rare and heating is not as much of an issue you can get away with less.

onedayglass.com will sell dual-paned insulated tempered glass.

I live in Wisconsin. -50 degrees to 100 degrees F ;-)

Right now I'm simply trying to decide whether to order 5/8" or 1/2" thick dual-paned insulated glass. I think both would probably work. With the 1/2", I can use thicker glazing tape and adjust the width of the trim. With the 5/8", I wouldn't want the final thickness to be more than 3/4" once set in caulk or 1/16" thick glazing tape and my trim would be a bit narrower.

So if I lay a beak of caulk, I suspect that a 5/8" unit would probably work and leave me plenty of room for the trim. ?

[Alex Zeller]

The caulking will be so thin that you will not need to account for it. The glazing tape is either going to be double side sticky foam or a butyl (sticky rubbery stuff). You are correct that you will have to account for the glazing tape. With temperatures that low I would want as thick of insulating glass as I could get. I would also get it argon filled. The Low E coating is worth it but it does have a slight greenish to yellowish tint to it.

[Tom M King]

It will come Argon filled. You can order it almost any way you want. Last year, I put in 10-20"x48" custom skylights in a standing seam roof job. I ordered it with 1/4" laminated safety glass for the bottom layer, 1/2" spacer for total of 1" thick, and 1/4" tempered bronze glass for the outer layer. The price came to not quite $200 per unit delivered. I just ordered it through the nearest glass company.

[Tim Bueler]

Here's another thought. This is in reference to a Therma-Tru because it's what's readily available in my area but I imagine any national mfr would be similar. The door I have is 1/2 Lite. I ordered it with obscure glass and later decided I wanted clear glass. I went to the local lumber yard where I bought the door and simply had them order me a "replacement" glass for the size of door I have. Quick switch and didn't cost nearly as much as I thought it would and came with the proprietary plastic stops (which you obviously won't use).

It got me to thinking I could just go through their catalog and order a "replacement" glass if I were building a door and wanted something fancier. I would order the glass first and make the door fit the glass. This would, of course, limit/change some of the design parameters but could be a decent trade off between design, cost and availability.

A long time ago (in a city far, far away) I did a remodel for a customer who had a mud room entry/porch with single pane, stopped-in glazing. I just ordered IGU's from the local glass company and swapped them out for the single pane. I bedded the IGU's in a high quality caulk. Can't remember how long ago that's been (decades) but it is still in service and functioning as desired.

[Peter Kelly]

So if I lay a beak of caulk, I suspect that a 5/8" unit would probably work and leave me plenty of room for the trim. ?

If you bed the IGU in silicone or caulk, it'll be difficult to remove if there's a problem. A foam strip around the outer-facing side will fill the gap similarly.

[Tom M King]

That's why I use cheap latex caulking to bed glass in. You can squeeze it down to almost nothing, but it's good enough for a gasket that good quality paint, or varnish can span over at the glass/wood intersection. That's the only thing I use it for. It will release easily in 35 years, but still stays there serving its purpose in the meantime as long as it stays coated on the outside.

I tested every glazing compound I could find, some years ago. One cost something like 15 dollars a tube. It lasted, but you had to break glass, and tear out little chunks of wood to get it out.

I expect the real reason for tape is so that the glazier can do the job quickly. Even with the cheap latex caulking, you need to wait a day, or two, to trim it without making a mess, so in this case, fast and cheap wins out over cheap.

[Mark Bolton]

I think you'll find that most quality custom door builders bed their IGUs in RTV. Ditch the tape all together.