Roof lantern opening too big

[microways85]

The opening for the roof lantern is slightly larger than the roof lantern. Therefore, an additional timber was added to the timber upstand to make it fit. Also lead flashing and silicone were used to make better water tight. Could this cause problems and would the roof need to be removed and redone ?

 

[andypeters]

I also had exactly the same issue but my upstaged was even more overhanging the lantern than yours. My builder ordered the wrong size lantern this was 18 months ago and now has gone into liquidation and I hate to say it but I have nothing but issues ever since with leaks. We have had numerous roofers round trying to fix it but none successful as water keeps getting in. Spoke to korniche which is the make of the lantern and they advised the lantern should overhang the upstand by a minimum of 12mm to drain away. I am now contemplating whether to purchase a new correct size lantern or if I'm able to cut back the upstand. Either way its going to cost thousands to repair. I must say though your roofers work looks a lot better than mine. Please let me know how you get on.

 

[microways85]

I also had exactly the same issue but my upstaged was even more overhanging the lantern than yours. My builder ordered the wrong size lantern this was 18 months ago and now has gone into liquidation and I hate to say it but I have nothing but issues ever since with leaks. We have had numerous roofers round trying to fix it but none successful as water keeps getting in. Spoke to korniche which is the make of the lantern and they advised the lantern should overhang the upstand by a minimum of 12mm to drain away. I am now contemplating whether to purchase a new correct size lantern or if I'm able to cut back the upstand. Either way its going to cost thousands to repair. I must say though your roofers work looks a lot better than mine. Please let me know how you get on.

Wow really sorry to hear this . Mine does not leak so I have just left it as it is .

 

[Notch7]

I also had exactly the same issue but my upstaged was even more overhanging the lantern than yours. My builder ordered the wrong size lantern this was 18 months ago and now has gone into liquidation and I hate to say it but I have nothing but issues ever since with leaks. We have had numerous roofers round trying to fix it but none successful as water keeps getting in. Spoke to korniche which is the make of the lantern and they advised the lantern should overhang the upstand by a minimum of 12mm to drain away. I am now contemplating whether to purchase a new correct size lantern or if I'm able to cut back the upstand. Either way its going to cost thousands to repair. I must say though your roofers work looks a lot better than mine. Please let me know how you get on.

Doesn’t look like a huge problem to sort out.

If it was me, I would screw a new timber upstand inside the existing one, to form the correct size, but it needs to be say 75mm higher, that will form a rebate, which will create a weather check.

I have to say making the lantern structural opening is a bit of a schoolboy error, I made many large orangeries and the lanterns which were upto 6m x 3.5m, never made the opening the wrong size

 

[noseall]

never made the opening the wrong size

We just make an opening and measure it - then get the lantern made. Surely that's what people do, innit? Like UPVC windows?

If for what ever reason I was to use a proprietary, ready made fella, then I'd research or ask for info' regarding finished carcassing sizes.

 

[Notch7]

We just make an opening and measure it - then get the lantern made. Surely that's what people do, innit? Like UPVC windows?

If for what ever reason I was to use a proprietary, ready made fella, then I'd research or ask for info' regarding finished carcassing sizes.

When I was making timber orangeries, we made in the factory: the doors, windows, flat roof kit and lantern.

For scheduling purposes the builders would begin the base whilst the joinery shop made all the above and it all ran together and went to site as a kit. It allowed the orangery to be erected and flat roof + fascia, then a couple of days for GRP, then lantern in and glazed. It was possible to get the structure weathertight in around 7 working days. After that my guys would start doing all the decorative trims like post covers, capital blocks, external cills, window boards etc whilst 1st fix services, screeding, plasterboarding etc was being done.

That’s the reason the timber lantern size was specified at the beginning rather than measure the hole.

To make it work, I did a working drawing of the roof to specify all the parts including lantern size.


But I can certainly see the logic in treating the lantern hole like a door or window for a builder on site: make the opening first then order the lantern