Friends,
I’ve moved to the Arizona a couple of years ago, and am still adjusting to flatroofs et al. I am used to installing skylights in pitched roofs with adequately sized rafters to vent.
Since I’ve been here I have installed only one skylight, a Home Depot rectangular job raised on an aluminum pedestal, which ended up having condensation problems. I’ve been asked to install another similar skylight, and the roof has all the same characteristics, and I am wondering what I can do to fix the condensation buildup on the inside.
Here’s the situation: These roofs are pitched 2/12″ and are made up of 4×6 rafters with 1x T&G sheathing, which is then covered in 2″ of fiberboard insulation, all covered by a felt and flat roofing, and white elastomeric. Inside the rafters are sheetrocked, but are more often open to the 1x T&G.
How can I vent in this situation? Or in any case prevent water collecting up there.
Thanks, Steve
Replies
condensation, IMO, is common on skylights. If any condensation will appear anywhere in the house, it will show up on a skylight. Reason is that warm moist air usually moves up ( that is where most skylights are installed too) and it will condense on a surface that is cooler. Glass, even insulated glass, is not a good thermal barrier.
You can get some help by providing an operating lite to act as a vent.
IMO Velux is THE skylight to use.
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Piffin,
Thanks for your reply. I suspected as much but wanted see if I was missing anything. The tilting Velux is a good suggestion.
I am guessing that the desert climate may make condensation worse, as the days can be very hot, heating the thermal mass of the house, and then the outside air temps can cool quickly in the evening.
Thanks, Steve