Replacing glazing units in lean to conservatory

[SenileGit]

Hi, I have an old conservatory (over thirty years old) and most of the double glazing units have got cracks in, and several of the units have water in, about six inches of it, as the units have failed.
I was given a quote from a builder for £4,000 to replace all of the roof glazing units, there are ten of them, eight are 60cm wide and the two end ones are slightly smaller, maybe 45cm wide (I haven't measured them yet), and they are 225cm long. The builder said that he needs to remove three courses of bricks above the flashings because he needs to install 'weep vents' or something, and seems to be claiming that the reason there is water in the glazing units is because of condensation within the cavity wall. I am sure the units have water in because the units have failed in the sunlight, I had two windows above the conservatory fail in the same way a few years ago. Am I right that there is no need for 'weep vents' or whatever they are called?
I want to change the glass units myself - I have already replaced all the glazing units in my bathroom and bedroom windows, which had external beading and were a long job, as they had double sided glazing tape which took a long time to remove. I've got a rough estimate of the price of one pane from a website I bought the sealed units for my bathroom and bedroom from last year - about £60 a unit - but those are standard double glazed units, not suitable for a conservatory roof - mine has wire mesh as you can see in my first photo below, so I presume I have to have that in the new units, which will cost a bit more.

Here is an internal view of the crack in the left pane, and several inches of water in the right pane.





This is a view of what appears to be some kind of sealant (2) (although it is now quite hard and brittle) inside, which the glazing unit rests on (in the gap (1)) - would I have to replace this? I presume so.
(3) is the main bar that holds up the glazing, I refer to it later on in this post.



Here is another view of the main bar (3) from a different angle, in case it helps:




Here is a view of the outside, showing the top part of the main bar (3):



In the photo below, (4) is a screw that I presume holds a metal clip (5) in position, which holds metal holders (6) at the bottom of each glazing unit. (7) is a bar that clips onto the side of (8), which is the upright part of the main bar (3) from previous photos.
I presume that from outside I can undo the screw (4), remove the metal clip (5), then remove the bars (7) from each side, then remove the metal holder (6) and then hopefully the glazing unit will be able to be lifted up a little and then slid downwards, along the main bars that hold it up.




Here is a clearer view of the long bar 'clips' (7):



And here is an even clearer view of the one at the edge of the conservatory:



I am wondering how the installers managed to push the clips down all the way up to the flashings, after installing the glass originally. Obviously this one is at the end so can be accessed with a ladder, but most of the others are inaccessible for most of their length, because they're too far away from the gutter to reach.



There appears to be sealant or a rubber/flexible strip along the bars (7):





I don't think it can be sealant because I can't see how it would be possible to get it any further than a few feet up from the gutter, the glass is 225cm long.

Does anybody know if I should be able to do this repair myself (with the help of a friend), and if so, how? Many thanks in advance if anybody can guide me in the right direction.

 

[diy_fun_uk]

I wouldn't want to comment on whether or not you could/should tackle this yourself with a mate. Given the materials are all old, if you do decide to diy it, one thing you'd want to check prior to commencing work is that all removeable parts are still readily available (including clips etc) in case any break on removal. And although I'm happy to stand corrected, I'd say 'yes' in terms of replacing all seals, gaskets and sealants.

If you're slightly reluctant to diy it, why not obtain 3-4 x quotes from reputable tradespeople to see if anyone comes in at a more attractive price?

 

[crank39]

Arghh this is one of those jobs that could easily go south, to answer your first question about weep vents or perp vent well they just refer to letting water if any out of the cavity that might find its way in further up the wall, these will have no bearing on the glass units, none whatsoever, your builder is touting for extra works.

The wired glass you have is called Geogian wired rough cast or GWRC for short, glass shops are famiiar with both terms if you need to contact any in the future. That glass is totally the wrong glass to replace with now, nowadays in a roof you'd use 4mm toughened glass(2 panes as in double glazed), most modern roofing systems can accomodate 24mm and 28mm units with spacer bars of 16mm in case of 24mm units and 20mm bars for 28mm units, its impossible to tell how thick your units are, you'd have to slip off the white end closer fron the front ot the glass between the rafters and drop a tape measure, while thats off you can measure the width of the existing glass, the length is a guess, i normally slide the tape up the glass till it stops and add 15mm but thats on modern roofs, DO NOT DO THIS WITH YOURS, much better to slide the glass down couple of inches and drop a tape measure over the end

 

[SenileGit]

Thank you both for your replies. Can I buy new metal rafters with whatever sort of clips they use? I presume the existing rafters are fixed to the wooden batten that goes across the outside if my house, right at the top of the wall inside the conservatory, and are also fixed somehow to the top of the front of the conservatory.
I'm not going to even consider doing the job until the summer, as I want to find out everything I can about it first, and it's only cosmetic faults.
Thank you for confirming what I thought about the weep vents, I thought it didn't make any sense at the time.

 

[SenileGit]

crank39, are you saying that if I remove the white front piece (6) then I should be able to slide the glass unit out, without having to remove the clip (7)? I know from looking at the double glazed units from inside that the gap is narrower than the units I replaced in my bedroom and bathroom windows, which I think were 28mm.
Clear toughened glass would look nicer than the GWRC does too!

 

[crank39]

No you will have to remove it, it acts as an anti slip to stop the unit sliding down with its own weight, the side beads will need removing too to release pressure, it looks a very old roof system if funds allow can be changed easily and once measured will come as a kit, front ring beam, rear wall plate and rafters, starter rafters for each end including the cheeses for the sides

 

[Notch7]

You may need to replace the Ali rafters which I'd say are part of the glazing system

Something like these

https://www.theglazingshop.co.uk/self-supporting-roof-bars/anthracite-grey-glazing-bar.html

The chance of getting new capping to fit that profile are prob slim.

If you do, go for grey, it looks much smarter than white outside


Be careful taking down the glass, it won't be toughened somwill have edges as sharp as broken glass.

 

[SenileGit]

Many thanks for the advice, I will have a look at those ali rafters, Notch7! I think I may be better off buying one of their lean to roof kits and using polycarbonate instead of glass.

 

[screamer]

if you can fit wooden rafters, then polycarbonate sheets is what i'd do (i have this on my wee sun porch)