Conservation rooflight problems

[Doug71]

I fitted 17 Conservation rooflights from The Rooflight Company in my house conversion about 12 years ago, already well over half the double glazed units have broken down in them. I spoke to the Rooflight Company about it a few years ago when the units first started blowing but they weren't very helpful.

I didn't mind when only one or two had blown but now most of the windows have at least one misty pane it's starting to bug me.

Has anybody ever replaced the units in them, they are held in with some kind of mastic sealant?

Doesn't look very easy to do and obviously they are all up on the roof, most are hard to access.

They do look nice, really in keeping with the old building but they weren't cheap and I didn't expect to be replacing the glass in them anytime soon and obviously it's a big expensive job. None of the panes have blown in the windows or doors I made which were fitted at the same time.

Anybody got any experience with Conservation Rooflights?

Thanks in advance, Doug

 

[MikeG.]

Interesting. I specify these regularly.

 

[Harbo]

No experience of those units but I was very surprised that most double glazing units are only guaranteed for 5 or 10 yrs.
I’d assumed they would last for ever.

Rod

 

[Woody2Shoes]

I've only fitted/used Fakro or Velux rooflights - so far, so good - the oldest is about ten years.

Looking at yours on the supplier's website, some thoughts that occur to me:

- Mild steel frame. Possible thermal and electrochemical incompatibility with the aluminium spacer bar (the ones I've used have aluminium/timber frames).

- Fixing seems to rely on a triangular 'wedge of mastic' (I guess simulating the old putty) which needs to be chemically compatible with the gunk they used to seal the edge of the DGU and is a hostage to fortune because any crack/pinhole in it will trap moisture near to the edge of the DGU.

- There would appear to be no air gap around the DGU - such a gap is really useful to allow any moisture which does/will get in to the glazing rebate, to drain out under gravity.

They do look nice though! Cheers, W2S

 

[Doug71]

Yes they do look nice, they sit low down in the roof and have nice big shiny brass winders, just a shame the units are all failing.

In my mind (could be wrong) the problem is to do with the steel frames, the steel frames always feel cold internally. The rooflights have a kind of plastic internal liner (mine have anyway) which it says is to avoid condensation problems i.e. the warm air in the room hits the cold steel frame and you get water forming on the steel frame, the liner is supposed to avoid this or at least make sure it doesn't drip in to the room. This makes me think you will also get condensation between the steel sash frame and DG unit causing premature failure.

The only other problem I have had with them was I they told "Yes we supply blinds for them" and "Yes we supply gas struts if you need it to be an escape window", it was only after I had bought all the blinds and gas struts and struggled with fitting them I was told "No you can't fit blinds and gas struts to the same window." #-o

 

[Woody2Shoes]

Yes they do look nice, they sit low down in the roof and have nice big shiny brass winders, just a shame the units are all failing.

In my mind (could be wrong) the problem is to do with the steel frames, the steel frames always feel cold internally. The rooflights have a kind of plastic internal liner (mine have anyway) which it says is to avoid condensation problems i.e. the warm air in the room hits the cold steel frame and you get water forming on the steel frame, the liner is supposed to avoid this or at least make sure it doesn't drip in to the room. This makes me think you will also get condensation between the steel sash frame and DG unit causing premature failure.

The only other problem I have had with them was I they told "Yes we supply blinds for them" and "Yes we supply gas struts if you need it to be an escape window", it was only after I had bought all the blinds and gas struts and struggled with fitting them I was told "No you can't fit blinds and gas struts to the same window." #-o

Sounds like the DGU is under siege from moisture inside and out! I hadn't clocked that the frame/sash is not thermally broken - that does seem like a shortcoming in any event.

 

[owen]

I've fitted around 15 of these in the past 5 years or so and none of them have had that problem that I've notcied, they're in a couple of holiday lets that I regularly do maintenance on so I see them quite often. Can you buy the actual moving sash seperately for them? It would be very easy to change that, it's only a few nuts and bolts.

 

[Nigel Burden]

No experience of those units but I was very surprised that most double glazing units are only guaranteed for 5 or 10 yrs.
I’d assumed they would last for ever.

Rod

Not roof units, but my double glazing units are now approaching 35 years old, and the only problem so far was a replacement hinge.

Nigel.