Issue with lantern fit advice required

[swebb99]

Hi I'm currently in the process of having an extension being built and this includes two lanterns on the GRP flat roof. They were fitted a few weeks ago by the window company who the builder deals with. I was happy with them and the build has been progressing.

However the other night I took a closer look and noticed that the base of both lanterns were not fitted directly (with sealant under) on to the upstands. Instead it appears the bases of the lanterns are just a touch too small and the fitter rested the down lip at the edge of both lanterns on the upstand and then just screwed in to the wood (not very far) and left a 1/2" gap. You can actually see out in places.

I've now spoke to the builder about this and he is just as shocked at me. To be honest I'm not surprised he didn't notice because he would have expected them to be fitted correctly and unless you get on the ladder and take a good look it would be easy to miss. I'm shocked the fitter thinks what he was doing is ok though.

The builder has spoken to the window company and they are returning next week to take a look. Am I correct that this really isn't how they should be fitted and if so that it is likely the both windows need removing and probably new ones made up ? I suspect the bases can't be changed by themselves.

Basically am I correct in being shocked and correct that my feeling is that they should have surveyed the upstands correctly, measured up and it is now there problem to correct.

Thanks

 

[^woody^]

It appears that the gap could be filled from the inside, and sealant applied externally.

 

[swebb99]

Surely that is a hack though, shouldn't require that on a new roof and lanterns. That frame needs to be sitting straight on the up stand with sealant (a normal amount, a bead) pressed between them. Also I would have assume the 90 degree angle at the base would have sealant between the joints of the metal base frame as well.

 

[Notch7]

The pics dont show whats going on.

Is the lantern too big, or is the upstand too wide.

Who measured it? -often the lantern is ordered before the upstand is formed.

Or, the surveyor comes to site and the openings are boarded and tarped over, so the internals are measured and the builder says what the upstand make up is.

I see some numpty plasterer has skimmed the reveals, finishing to nothing
Or did the builder tell him 'dont worry, itll be trimmed over

The only problem is if internally the plasterboard sits proud of the lantern baseplate leaving nothing for the plaster to finish to.

It looks to me as though internally it needs a windowboard shaped moulding, sticking out from the plasterboard by say 30mm or so. Then a simple flat trim with a chamfer pinned to the plasterboard -which will cover any shrinkage cracks.

 

[swebb99]

Hi thanks for the reply.

I'm still waiting to talk to the builder who has already spoken to the window guy. At the moment I'm not clear who measured but I do know it would have been after the upstand was complete but maybe not with the GRP on it. Nothing was covered at the weather was great for a few days!

The issue seems to be that all the way around the bottom of the lantern there is bend/lip at 90 degrees down off the bottom of the lantern base which is obviously supposed to sit over the edge of the upstand allowing the rest of the base to sit flat on the top of the upstand. However all the way around the lip is just shy width and length of the upstand external diameter so the fitter has just rested the frame on the upstand using the lip and used the screws to hold it down. So internally there is a 1/2" or so gap which you can see and externally in places where the upstand isn't perfectly flat the lip leaves a mill or two of gap.

As for the plastering I'm not sure what you mean. Do you mean he has just plastered to the top and it will slowly crack off from the top if left and it should be covered in some way? Sorry im new to plastering.

Oh one last thing, the plasterboard top would not interfere with the lantern base if it was fitted correctly.

Thanks

 

[Notch7]

Hi thanks for the reply.

I'm still waiting to talk to the builder who has already spoken to the window guy. At the moment I'm not clear who measured but I do know it would have been after the upstand was complete but maybe not with the GRP on it. Nothing was covered at the weather was great for a few days!

The issue seems to be that all the way around the bottom of the lantern there is bend/lip at 90 degrees down off the bottom of the lantern base which is obviously supposed to sit over the edge of the upstand allowing the rest of the base to sit flat on the top of the upstand. However all the way around the lip is just shy width and length of the upstand external diameter so the fitter has just rested the frame on the upstand using the lip and used the screws to hold it down. So internally there is a 1/2" or so gap which you can see and externally in places where the upstand isn't perfectly flat the lip leaves a mill or two of gap.

As for the plastering I'm not sure what you mean. Do you mean he has just plastered to the top and it will slowly crack off from the top if left and it should be covered in some way? Sorry im new to plastering.

Oh one last thing, the plasterboard top would not interfere with the lantern base if it was fitted correctly.

Thanks

Without seeing the measurements, I cant tell, however to eliminate the gap and have it sitting correctly, the lanterns could be removed and some timber fitted onto the upstand top, say 70x 20 flush to the inside. Then sit the lantern back in place, the lip can sit over the 70 x 20 and the base of the lantern would sit nice and snug on top.

You seem concerned about the gap -but in building terms thats no issue at all. If the lip isnt meant to be load bearing there should have been packers to suppirt the lantern.

Im not sure if theres a major dimension issue or the lantern installation is just not completed. My guess is its a cosmetic issue.

It is standard practice to pack out frames to fit to structural openings. Usualky the customer doesnt see as its hidden behind trims or plaster.


The problem with the plasterboard is that it stops mid air. It shouldnt do, it should stop against a trim of some sort.

 

[swebb99]

Thanks again for the reply.

I'm seeing the builder tonight so I'll ask him some questions. The reason for the concern about the lip is really that at the moment there is a gap in various places around it that from inside the building you can see out of and see the garden and brickwork on the other side. So basically there is no seal going on and I'd question why I bothered fitting a eco double glazed unit if there is a 1/2" gap and then in various places no obstical to the outside world. Obviously heat is escaping and I can hear sound from outside to like a slightly ajar window.

As you say they might be able to remove the lantern and screw some boarding on to the top of the upstand and then re-sit the lantern over this and screw on. It's not ideal to be honest as it's fairly obvious looking at it how the designer of the lantern expected it to be fitted but it might be a way forward.

I'll ask about the trim. My father replied to an email and made the same point 15 mins ago !

Great to get some useful feedback, thank you

PS: If you look at both photos, on the top one at the base of the corner of the lantern you can just make out a gap between the bottom alloy lip and the upstand. On the bottom one past the screws you can make out a bright line, thats the same gap but on the inside.

 

[swebb99]

Just an update. The owner of the window company took a look and agreed they weren't fitted correctly and the measurements were about 10mm under for width or height. He gave me two options, he would remake new lanterns or he would make some adjustments to make them fit and reduce the cost. After some thought I decided I'd be happier if they were remade correctly and to be fair to him he was totally ok with this. So with any luck in a week or so I will have lanterns that fit correctly and give me long, un-concerning service