Alternatives to glass for glazing a door?

[Nick]

We have a door leading from the kitchen to a utility room and thence to the back garden. It is probably the most used door in the house. This door is steel framed with individual leaded lights. The problem is that as cats & dogs return from the garden they batter at the door to be let in. This has ripped the lead flashings away and the door is now becoming unsafe. I'm thinking of removing the lower glazed part (approx. 550 x 1350mm) and replacing with a single sheet of some clear plastic type material. The upper glazing is a single sheet of glass of similar dimensions so what I propose should not be out of character.

I'm thinking of using Makrolon / Lexan (don't know the difference but suspect Makrolon is a trade name). Would this be suitable, or can anyone suggest a better alternative? Thickness would be 10-13mm. Must be clear, *reasonably* unbreakable, and hopefully scratchproof. I would intend to fix it by bedding into silicone and c'sunk machine screws at 100mm centres. Any ideas or alternatives please? Also any links to suppliers?

Many thanks

Nick.

[Peter Parry]

Wow.

It would be that, initially.

It would be easier to get through the wall than 13mm of Polycarbonate (Both Makrolon and Lexan are trade names). The door and frame and surrounding brickwork would give way first. In fact most of the house would be gone before the Polycarbonate.

Not a hope, neither are at all scratch proof and will mark quite quickly. Both have abrasion resistant versions but they won't stay glass clear for long. Makrolon Hygard is a polycarbonate/polyurethane laminate with a hard coating and may stay clearer longer. 13mm of it might be mildly expensive but would have the advantage that it will stop most handgun bullets if needed!

Polycarbonate expands quite a lot when heated. You would need to allow for expansion to avoid distorting the door.

Laminated glass?

[Richard Faulkner]

In message , Nick writes

I have a security issue with a ground floor flat and my builder has suggested new laminated double glazed glass for the patio door and adjacent windows - he tells me that the frames and brickwork will give way before the glass.

He described it as a piece of "plastic glass" sandwiched between two normal sheets of glass - presumably as scratch proof as normal glass?

[Bob Mannix]

It is normal glass (two sheets of it making a sandwich with a plastic sheet filler between them). It is recommended for patio doors where there are football kickers in the garden etc. (they have to be toughened or laminated). My patio door double glazed units are laminated on the outside and toughened inside.

They fail (if at all) fairly benignly. Mine developed a crack at the edge and had to be replaced. A toughened sheet would have shattered. This stayed secure and was merely unsightly as the crack slowly lengthened.

It depends how you attack them, I guess but I would agree a laminated patio door unit is not going to be the weakest point in the house.

To cut laminated glass, one side is scored and cracked and a strip of meths run along the crack and ignited. The heat softens the plastic so the gap can be opened up enough to get a blade in to cut the plastic. The other sheet can then be snapped along the line. (I watched it being done once).

[fred]

In article , Richard Faulkner writes

If it's a large pane (half door panel & up) then he is being a tad over optimistic. There is a failure mode (which I won't describe) which makes standard (6.4mm) laminate less than perfect. If you are getting super thick stuff or a multi-layered sandwich then things get better. The risks can be reduced if you install the panes with security glazing tape which is 2mm or so dense foam strip with a high strength adhesive both sides.

I'll be from my comp for a while so won't be able to respond to any replies but I discussed this with Andy Hall in an old thread when he was doing something similar, google, or he may step in to say how he got on.

HTH

[The Wanderer]

Is the amount of light an issue? You are saying it must be clear, but why not just use a suitable exterior grade ply panel? Half-glazed doors are very common.

[Nick]

Many thanks Peter, one lives & learns. I didn't want to use glass but it appears that may be the best option. Mildly expensive is perhaps something of an understatement :) Nick.

[Nick]

Thanks Wanderer, ingress of natural light is a very major concern. Nick.

[sylva]

I don't think polycarbonate is an option for you but I do drive machines with it, laminated glass would not survive a day. Those machines fitted with margard stay clear in the area swept by the windscreen wipers, the german machine which is < 1 year old has been badly affected by the abrasion, I suspect a cheaper product has been used.

AJH

[bigcat]

unless you tell us what the problem is with glass, i dont see how we can help. I'd use laminated or better toughened. Both are burglar reistant, but neither burglar proof, and certainly will give way before frames, walls, etc.

NT

[ThePunisher]

Brett Martin do exactly what you want but I dont know how small an order they will take.