Glazing interior window

[jlawford]

Hi All,
Gone and cracked an interior window, oh, only about five years ago and had a piece of cardboard covering it ever since! It's an internal window next to the front-door but we have a porch with its own modern UPVC door so it's never caused too many issues apart from a little draught every now and again.

Now it's finally annoying me, and I want to repaint the whole frame anyway.

So I'm going to replace both panes of glass so they match - it's traditionally fitted with putty, so I'll just rip that all out, clean up the frame, and install with beading, fill any gaps and paint to match the frame.

Any issues with me adding secondary glazing to the inside of the frame (see picture)?

There's a perfect rebate all round just dying to get glazed! Just need to add an extra piece of framing to separate the internal glass pieces.

 

[Gordon Tarling]

If that's adjacent to a door, I'm fairly sure that you need to use safety glass. I don't see any other issues though.

G.

 

[Jacob]

Unless it's a DG sealed unit with the outside glass it will mist up and eventually go mouldy, unless removable for cleaning. Simpler to just have thicker curtains etc
Putty better than beading for external glazing.

 

[Spectric]

All interior glass below a certain height has to be safety glass, I believe doors with many small panes are exempt and because of the high levels of thieving scumbags around it should be glazed from the inside so it cannot be removed from outside, even then some decorative iron work on the inside will make it less vunerable.

 

[Doug71]

As said needs to be safety glass if within 300mm of a door so needs to be toughened or laminated. That pattern is called Flemish if you want to just replace the broken pane.

 

[woodieallen]

I know it makes sense to be toughened but....in this particular instance, I'm not sure that the rules are valid. He's not replacing anything. He's not putting in something like a completely new window.

I'm reminded of this because we are in the process of selling out late mothers flat and there's a misted DGU. Buyers solicitor getting all hot and bothered about a FENSA certificate. Not needed here.

 

[ian33a]

Adjacent to a door or 800mm or less above floor height means that any replacement pane of glass needs to be toughened. Glass type is, indeed, Flemish.

A secondary pane wont make much difference from an insulation perspective as, in free air, the ideal gap between the two panes should be about 16mm. Anything more will allow convection currents of air and will not work especially well.

You could chisel out the putty and either re-putty it or put in beads. Beads are easier to install. Depending upon space available, you may have enough space to add a double glazing unit with a slim bead. You could add an argon filled unit and will be able to get away with a depth of unit of 4+12+ 4 (20mm) and will get some thermal benefit. Just ensure that all glass fitted is toughened. It's only worth doing if the door is also double glazed. If it isn't, the surface area of glass in the door likely dominates the aspect and the savings on side windows is minimal. Even less given that the porch is already double glazed uPVC.

Some schools of thought are that any glazing in wood is best done with toughened glass irrespective of legality because wood has a habit of moving thermally and can crack clear float glass. For the small additional cost of toughened, its worth doing it anyway.

Glazing repairs don't attract FENSA interest and this is why repairs don't come with FENSA certificates even though solicitors get hot under the collar about it.

 

[Doug71]

I know it makes sense to be toughened but....in this particular instance, I'm not sure that the rules are valid. He's not replacing anything. He's not putting in something like a completely new window.

I'm reminded of this because we are in the process of selling out late mothers flat and there's a misted DGU. Buyers solicitor getting all hot and bothered about a FENSA certificate. Not needed here.

He is replacing a pane of glass in what is classed as a 'Critical Location' so needs to be toughened.

I use toughened for everything, one reason is the edges are nice and smooth so you don't cut yourself when installing it

 

[jlawford]

Unless it's a DG sealed unit with the outside glass it will mist up and eventually go mouldy, unless removable for cleaning. Simpler to just have thicker curtains etc
Putty better than beading for external glazing.

Sounds like buying a couple of custom sized DG sealed units could be worth it. There is enough depth to get a fairly slim one in.

Only problem is, there is no edge to the frame; i.e. the unit would pass from one side to the other. Can I fit a sealed unit within a frame, and bead from both sides? Or reframe one side completely which I guess is similar.

These windows are inside the porch leading to the main house.

The porch door is a modern UPVC with anti-snap locks and anti-break handles (both of which have actually resisted attack on a different door!) The larger panel is only 380x1,120 - I wouldn't fancy getting through that gap.

Yep, 300mm from a door needs safety glass and I'd do that for peace of mind anyway. We originally cracked the glass with a buggy leaned up against it inside the porch...didn't take much pressure.

 

[ian33a]

You could bead from both sides. Ideally you need 2 to 5mm air gap between the edge of the glazing unit and the frame of the unit in which you are placing it. The gap needs to prevail on all four sides of the glazing unit. This allows for material expansion and for the bypassing of condensation. You also need approximately 11mm coverage of the bead over the glass so that the primary seals of the glazing unit are not exposed. If you don't you risk shortening the life of the glazing unit. Given that, something like an 18mm bead all around on both sides should suffice. A thin decorators caulk bead between the glazing unit and the wooden beads on the porch side will hold everything in place if you wish to paint it. Otherwise use a low modulus silicone bead.

 

[jlawford]

You could bead from both sides. Ideally you need 2 to 5mm air gap between the edge of the glazing unit and the frame of the unit in which you are placing it. The gap needs to prevail on all four sides of the glazing unit. This allows for material expansion and for the bypassing of condensation. You also need approximately 11mm coverage of the bead over the glass so that the primary seals of the glazing unit are not exposed. If you don't you risk shortening the life of the glazing unit. Given that, something like an 18mm bead all around on both sides should suffice. A thin decorators caulk bead between the glazing unit and the wooden beads on the porch side will hold everything in place if you wish to paint it. Otherwise use a low modulus silicone bead.

Thanks, I somehow missed your first reply which was also very useful.

Never done windows before, but I'm looking at the frame and approaching it more from a woodworking perspective - which I can do...can't be beyond the wit of common man but worth checking before I make any fundamental errors!

- Strip out old glass and putty, clean up the frames.
- Fit new sealed unit with packers to maintain an air gap around the whole unit.
- Dry glazing tape on the glass so the bead sticks and creates a seal?
- Bead from both sides (do one side before fitting the glass).

The gap is 25mm, but if you look at my original photo, there is a plenty of width to add a bead using the outer parts of the frame. Will have to think about how to make it look neat.

 

[ian33a]

Thanks, I somehow missed your first reply which was also very useful.

Never done windows before, but I'm looking at the frame and approaching it more from a woodworking perspective - which I can do...can't be beyond the wit of common man but worth checking before I make any fundamental errors!

- Strip out old glass and putty, clean up the frames.
- Fit new sealed unit with packers to maintain an air gap around the whole unit.
- Dry glazing tape on the glass so the bead sticks and creates a seal?
- Bead from both sides (do one side before fitting the glass).

The gap is 25mm, but if you look at my original photo, there is a plenty of width to add a bead using the outer parts of the frame. Will have to think about how to make it look neat.

I'd be inclined to get the cracked glass out and then clean up everything in the void. Then I would create a bead on the inside which has a profile and size to hold the glass and cover the primary seal.

Now run a line of caulk or low modulus silicone all around the inside of the bead.

With a pre purchased glazing unit which is about 4-5mm smaller than the thinnest dimension of the frame in X and Y all around (so 8-10 absolute), raise it above the bottom of the frame by about 5mm using packers. Put the glass onto the packers and offer it against the silicone. Gently push to cause suction and it should hold in place. If you wish you can add packers to the vertical sides and top but it isn't essential.

Now, with the beads that you plan to use on the porch side, offer them in place one by one, having placed a bead of caulk or silicon on the mating surface with the glass. Then gently nail them in place and fill the surface with a suitable filler.

Glazing tape is fine but its really intended as a quick install for uPVC with a decent level of security. Unless you use a very thing tape, it will show.

 

[jlawford]

I'd be inclined to get the cracked glass out and then clean up everything in the void. Then I would create a bead on the inside which has a profile and size to hold the glass and cover the primary seal.

Now run a line of caulk or low modulus silicone all around the inside of the bead.

With a pre purchased glazing unit which is about 4-5mm smaller than the thinnest dimension of the frame in X and Y all around (so 8-10 absolute), raise it above the bottom of the frame by about 5mm using packers. Put the glass onto the packers and offer it against the silicone. Gently push to cause suction and it should hold in place. If you wish you can add packers to the vertical sides and top but it isn't essential.

Now, with the beads that you plan to use on the porch side, offer them in place one by one, having placed a bead of caulk or silicon on the mating surface with the glass. Then gently nail them in place and fill the surface with a suitable filler.

Glazing tape is fine but its really intended as a quick install for uPVC with a decent level of security. Unless you use a very thing tape, it will show.

Amazing - clear and useful, many thanks.

 

[Sandyn]

I know it makes sense to be toughened but....in this particular instance, I'm not sure that the rules are valid. He's not replacing anything. He's not putting in something like a completely new window.

I would never use anything but toughened for internal glass panes. My daughter put her hand through an internal window in a door, just like the one in your picture. I was amazed just how easily it happened. She was messing about of course. I was right beside her when it happened. She had to have one of the tendons repaired and other repairs done inside the hand. The little dark rectangular area had a very poor blood supply, There was a high probability she would need a skin graft to repair that bit. Fortunately the blood supply was OK. About 10 years after it happened, a couple of bits of glass came to the surface.

Was pretty horrific when the doctor pulled the flap of skin back to clean out the wound. I had never seen the inside of a hand before. I anticipated my reaction and had wedged myself between the bed and the wall, so I couldn't fall over. Was my wee girl, so had to be there.
Was a horrible thing to see, but she was so lucky it wasn't much worse.

 

[ian33a]

I would never use anything but toughened for internal glass panes. My daughter put her hand through an internal window in a door, just like the one in your picture. I was amazed just how easily it happened. She was messing about of course. I was right beside her when it happened. She had to have one of the tendons repaired and other repairs done inside the hand. The little dark rectangular area had a very poor blood supply, There was a high probability she would need a skin graft to repair that bit. Fortunately the blood supply was OK. About 10 years after it happened, a couple of bits of glass came to the surface.

Was pretty horrific when the doctor pulled the flap of skin back to clean out the wound. I had never seen the inside of a hand before. I anticipated my reaction and had wedged myself between the bed and the wall, so I couldn't fall over. Was my wee girl, so had to be there.
Was a horrible thing to see, but she was so lucky it wasn't much worse.

View attachment 119851

That's horrible and must have been so worrying as a parent.

The problem with toughened glass is that, if you let it hit a solid object at the wrong angle it breaks, instantly, into very small, but quite sharp cubes, and is rendered useless. There are specifications which dictate how many cubes per square inch it must break into. It's all very regulated.

While toughened glass costs a little bit more than clear float, in almost every other respect it is a better alternative for most users. Above a certain size most manufacturers will only supply toughened (it varies by manufacturer) and, even in smaller sizes, if the glazing unit whips or is put under slight stress it will crack and can cause similar injuries to the above.

There is seldom, in my mind, a case whereby clear float is acceptable where there is any risk of it breaking easily is justified.

 

[baldkev]

You can also buy stepped double glazed units, so the outside face sits where the flemish is, and the interior piece of glass in the stepped unit would fit within the opening ( as said, usually leave 4 or 5mm all round and caulk in the gap )

 

[David Young]

Hi All,
Gone and cracked an interior window, oh, only about five years ago and had a piece of cardboard covering it ever since! It's an internal window next to the front-door but we have a porch with its own modern UPVC door so it's never caused too many issues apart from a little draught every now and again.

Now it's finally annoying me, and I want to repaint the whole frame anyway.

So I'm going to replace both panes of glass so they match - it's traditionally fitted with putty, so I'll just rip that all out, clean up the frame, and install with beading, fill any gaps and paint to match the frame.

Any issues with me adding secondary glazing to the inside of the frame (see picture)?

There's a perfect rebate all round just dying to get glazed! Just need to add an extra piece of framing to separate the internal glass pieces.

View attachment 119815

I'd be tempted to put a double glazed unit in instead of a single pain. You can get stepped units so one piece if glass is larger than the other, enabling it to be fitted without having to rebate any deeper. You can then put a beading on the inside.

 

[Limey Lurker]

Definitely Flemish; and it's looks as if it was fitted upside-down!