Old aluminium sliding patio door: replace sealed unit or replace whole door?

[JJack18]

Hi all

I have an old aluminium sliding patio door in the UK.

The outer pane of the double-glazed unit has shattered, but the inner pane is still intact. The door is old but currently still usable, and the broken outer pane is not an immediate safety issue because the area is cordoned off.

A local window company has quoted around £400 including VAT and fitting to replace the sealed unit. However, they warned that because it is an old aluminium wrap-around door, dismantling it could be risky due to perished seals and seized/rusted screws. They said it could turn into a nightmare and lead to additional costs.

They also suggested replacing the whole thing with new French doors for around £900 instead.

My questions are:

1. Is replacing the sealed unit in an old aluminium sliding patio door usually straightforward, or is it genuinely risky?
2. If it does become a “nightmare”, what sort of additional cost might realistically arise?
3. In real life, how often do these jobs turn into “once dismantled, it really needs full replacement”?
4. Would you repair the glass only, or replace the whole door?
5. Do £400 for glass replacement and £900 for full replacement sound realistic in the UK?

Any advice from people with experience of older aluminium patio doors would be much appreciated.

 

[Wayners]

Glass £400 maybe but door is more imo.
Glass X2 just incase they break first attempt plus fitting is how they work out price.

If you like door and it's fine why not replace glass

 

[aveatry]

I would be looking at replace with new doors - if it is £900. Better thermal and so on espicually with Warm Edge Spacer Bar / coated glass and gass filled - was that spec in the £900 price

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[JJack18]

Glass £400 maybe but door is more imo.
Glass X2 just incase they break first attempt plus fitting is how they work out price.

If you like door and it's fine why not replace glass

The door itself opens and closes fine and is otherwise working normally. The damage was not due to the door failing, the outer pane was shattered by a small stone while I was mowing the lawn

Because of that, I would prefer not to spend more than necessary if the door itself is still fine

My main concern is that once the work starts, it could turn into the “nightmare” the company mentioned, with extra costs for perished seals / seized screws, and then end up not far off the cost of replacing the whole thing with new French doors

 

[aveatry]

The door itself opens and closes fine and is otherwise working normally. The damage was not due to the door failing, the outer pane was shattered by a small stone while I was mowing the lawn

Because of that, I would prefer not to spend more than necessary if the door itself is still fine

My main concern is that once the work starts, it could turn into the “nightmare” the company mentioned, with extra costs for perished seals / seized screws, and then end up not far off the cost of replacing the whole thing with new French doors

After many years of DIY almost everything has the potential of turning into a nightmare and often does. They seem quite honest and up front about things OR are they just being a bit lazy and replacing the whole lot its easier for them than just the glass.
Freak accident but if it happens again at least all the seals will be new

 

[Tigercubrider]

Get another couple of opinions from people that can see it?
Personally, I would replace unless money is tight or you have a real love for the thing.

A new frame will be thermally better, it will lock more securely, and probably be easier to open and close due to new tracks and wheels. The glazing can probably be thicker

 

[ronniecabers]

£900 seems remarkably cheap to replace a set of sliding doors to a set of French Doors , personally if you can stretch to the 900 id be tempted BUT I'm really wary of that price and therefore the quality of the doors and workmanship.
Wraparound Ali doors do suffer from screws that get stuck but penetrating oil helps, rubber seals can get stuck to the old unit but care taken can get them off in one piece. The ones ive taken apart never had any real issues and work on the basis if it takes the fitters longer than i quote it for , then thats on me and not the customer, so no extra costs should be incurred.

 

[crank39]

Yeah I thought £900 for a set of french doors is dirt cheap, I'd love to know what profile that would be but that said there's no real bad ones nowadays other than duraflex but they went pop in 23. In terms of replacing just the unit then yes as Ronnie says the wrap around seals can and do perish, can stick to the glass and tear when trying to remove but replacement seals are readily available but you'd really want them with you at the point of replacement otherwise your doing the job twice by stripping it all down again to fit the gasket