Skylights in new builds

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Insanekiwi

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#238223 7-Jul-2018 17:28

I wanted a couple of skylights in the kitchen but I am hearing horror stories about potential leakage and more of a hassle than benefits. Our home should get enough light to be honest.

It certainly improves aesthetics.

Any personal experiences and how much maintenance does it require? It’s planned for a new construction - and will be non vented one. The roof is coloursteel iron / shall I leave them out?!

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#2051291 8-Jul-2018 09:50

Lurking as we are completely rebuilding garage as man cave and are thinking about sky light.

scuwp

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#2051310 8-Jul-2018 10:15

If installed properly leaking shouldn't be a concern, particularly if designed in from new. 2 things to think about are how you will block the light coming in either for comfort or to prevent the area absolutely cooking in summer, and how to minimize heat loss in winter.

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empacher48

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#2051335 8-Jul-2018 10:36

Our house was built with a skylight in an internal bathroom. We've had no problem with it leaking (our roof is concrete tile), however what we should've done is paid the extra for one that remotely opens.

Being in a bathroom it provides a natural chimney for the moist hot air to rise into and there is no ventilation up there. If it was remotely opening then as the hot moist air rises, it will naturally vent outside. The remote opening also has a rain sensor that will close automatically should it detect any sign of rain.

Ours is triple glazed so there isn't much in the way of heat loss and there were options of having a blind installed in one of the layers if you required something to block the light. We didn't bother with the blind as it is in a roof of a bathroom.

Insanekiwi

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#2051360 8-Jul-2018 10:59

scuwp:
If installed properly leaking shouldn't be a concern, particularly if designed in from new. 2 things to think about are how you will block the light coming in either for comfort or to prevent the area absolutely cooking in summer, and how to minimize heat loss in winter.

Good points. I think it’s quite high up the roof (1.6m) cavity so unlikely to get direct light to the floor area. The 2 skylights have been highlighted in the capture attached. It’s a 3D render of our house.

raytaylor

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#2051388 8-Jul-2018 12:03

We had one in upper hutt - leaked.

Might not have been installed when originally built though - probably installed later.

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mattwnz

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#2051751 9-Jul-2018 00:35

Any hole through a roof (eg flue, skylight etc) could leak if not flashed properly. Comes down to detailing and workmanship. Council should also check the work to make sure it all complies.

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nickb800

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#2051754 9-Jul-2018 06:43

Council building inspectors generally don't inspect roofs - so your contractor is essentially self-certifying, thus you need to be fully confident in them. I'd go with a manufacturer accredited installer, so that you have a valid, decent warranty

mattwnz

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#2052362 10-Jul-2018 01:30

nickb800:

Council building inspectors generally don't inspect roofs - so your contractor is essentially self-certifying, thus you need to be fully confident in them. I'd go with a manufacturer accredited installer, so that you have a valid, decent warranty

This is such a good point. IMO Councils inspector should be checking the roof and all flashing that comply with E2 and the plans, but I don't think they want to get up on the roof. But I don't think this issue is related to just skylights, but also flues, chimneys and parapets.

froob

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#2052387 10-Jul-2018 08:37

I was actually surprised by the minimal amount that the council (WCC in my case) do inspect. On our pre-line inspection, none of the critical structural work was complete. This was installing alternative support from removing a wall. The council was only interested in insulation and a moisture test.

The wall we removed was quite rotten from a leaking chimney flashing. My suggestion would be to only have penetrations through the roof where absolutely necessary. Roof flashings do seem to be a common point of failure.

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RickW

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#2052408 10-Jul-2018 09:23

The point of failure in roof penetrations is when the flashings don’t run back under the ridge flashing. A lot of roofers out there don’t know how to flash things correctly and they are relying on silicon for waterproofing which you would be lucky to get 10 years out of.

mattwnz

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#2052680 10-Jul-2018 13:49

RickW: The point of failure in roof penetrations is when the flashings don’t run back under the ridge flashing. A lot of roofers out there don’t know how to flash things correctly and they are relying on silicon for waterproofing which you would be lucky to get 10 years out of.

It all basically comes down to workmanship. In the old days, they didn't used to use these big waterfall flashings all the up to the ridge, and they worked fine. The metal roofers code of practice has alternative flashing techniques to this, if you don't want these big ugly flashings all the way up to the ridgeline on your roof. You see some roofs where much of the roof is covered by these ugly flat flashings. The alternative isn't sealant, but proper underflashings.

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RickW

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#2052748 10-Jul-2018 14:54

mattwnz:
RickW: The point of failure in roof penetrations is when the flashings don’t run back under the ridge flashing. A lot of roofers out there don’t know how to flash things correctly and they are relying on silicon for waterproofing which you would be lucky to get 10 years out of.

It all basically comes down to workmanship. In the old days, they didn't used to use these big waterfall flashings all the up to the ridge, and they worked fine. The metal roofers code of practice has alternative flashing techniques to this, if you don't want these big ugly flashings all the way up to the ridgeline on your roof. You see some roofs where much of the roof is covered by these ugly flat flashings. The alternative isn't sealant, but proper underflashings.

100% incorrect. Any back gutter flashings will be reliant on silicon. The reason that the old flashings with back gutters diddnt leak is because they were soldered to the roof.

With the silicon as you get frosts condensation on the roof sucks between the flashings and then freezes which rips the silicon a little the more frosts the quicker the breakdown of the silicon. Also with a lot of snow you get the snow sitting on the roof and water sucking between the flashings.

mattwnz

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#2052754 10-Jul-2018 15:04

Flashings should always overlap over one another. Think about how feathers on a bird work. They should never rely on silicon as the primary flashing method.

Insanekiwi

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#2052756 10-Jul-2018 15:07

Overlap does make sense to me... I will ensure my builder does a good job on this... really good insight.

We don't have snow (probably very occasional) regularly in Wellington, but certainly will have frosting in the mornings in cold mornings. I decide to go ahead with the skylights as future retrospective installation will be very challenging.

RickW

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#2052761 10-Jul-2018 15:21

mattwnz:
Flashings should always overlap over one another. Think about how feathers on a bird work. They should never rely on silicon as the primary flashing method.

The ones in the picture have 200mm of cover but they are always relying silicon. Where you have 2 surfaces close together or touching you get water being sucked between the two surfaces in this case flashings, it’s called the capillary effect. Where the sheets are cut across at the top for the back gutter to run through it’s impossible to get any cover on that very point so that will always be relying 100% on silicon. The only way around this is to have a secondary flashing system running under the roof sheets all the way to the gutter that will catch water when the silicon deteriorates but if that is in contact with the sheets you will bet white rust forming between the two.

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