Need ideas on interim attic venting
Hello,
I am looking for ideas on how to vent my attic for the next 2 months.
I’m having my roof replaced in about 2 months. This will include the installation of a ridge vent.
Complicating this is that I’m having my home re-stucco’d next week and decided to cover up the existing gable vents, so that I don’t have unsightly patches later.
In hindsight, I should have planned the stucco for after the roof install. Given my situation, what ideas do you have for venting my attic for the next two months?
My attic gets really hot. 127 F yesterday at 4pm and it reached a high of 88 F outside. That’s almost 40 degrees hotter. Normally my attic is only 30 degrees hotter than the outside air.
I live in California in climate zone 4.
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Replies
The purpose of venting is not to cool the attic, it's to prevent the buildup of moisture. Normally that's only a problem when it's cooler outside than inside.
Interesting. I thought this would help cool my unventilated attic. My experience is that when I reduced the venting temps increased about 10 degrees F.
The reason attics are vented is to clear moisture. That venting cools them as well is a side effect.
If your concern is that your roof will be damaged by being unvented for a few months, I don't think that's a danger, particularly if it's outside the heating season.
If you want your attic to be cooler because it makes the rest of the house cooler, I think Bill is right in #6 that just doing the ridge vent now makes the most sense. I don't like the idea of using a fan to ventilate the space, unless your ceiling is well-sealed that will pull conditioned air from your living space and make you less comfortable and increase your energy usage.
In the long run the solution is to have good air sealing and insulation between the attic and the living space, in addition to ventilation. You also want to do as much as you can to get your ductwork well-sealed and on the conditioned-space side of the insulation.
Thanks. I think I will focus on the insulation and sealing (duct and ceiling) after the new roof is installed.
how do you plan to get air into the attic once the ridge vent is installed? are your redoing the soffits to add/increase vents, you could knock out the old ones and duct an extraction fan from the top of the attic and out the soffit., or you could open a bunch of soffit area and just put a box fan or two in the attic to stir things up and hopefully get some air exchange.
what is your concern with the the high temps? just thermal comfort in the occupied spaces? if so, how about just layering some additional insulation over the existing, might as well invest in something useful long term.
I have soffit vents. I like your idea of throwing a box fan up there. I may try that.
I have central air ducts and inadequate ceiling ventilation, so that bubble of hot air trapped in the attic heats my home (and poorly insulated ducts) for hours long after the outside air temp has dropped. AC runs very long.
When the roof is done, I’m going to seal up my ceiling and replace my old fiberglass batts with blown in.
If you're just worried about your ducts I might first try to mitigate radiant heat transfer with the hot underside of your roof, i could see a scenario where stirring the air would lead to higher conduction into the ducts because you could destratify the air, raising the air temperatures close to the ceiling (where i presume your ducts to be). Not sure if it would work but as a cheap experiment you could perhaps some aluminum foil shiny side up on top of the ducts, ideally not sitting directly on the ducts (e.g., throw a piece of scrap insulation between the foil and the ducts).
If it's not super humid, you might be OK with just the soffit vents if it's only for a relatively short period of time. MOISTURE is the big concern here, not HEAT in the attic.
It's pretty easy and quick to cut in a ridge vent though, usually you just run a circular saw along the ridge a few inches down on either side, then remove the sheathing from that area you cut out. The easiest/safest way to "temporarily" vent your attic is to probably install a few sections of cheap ridge vent, then replace them when the new roof goes on. You might even be able to reuse the ridge vents if you put them on temporarily with removeable fasteners (screws). You don't need to put the whole ridge vent in, just 2-3 sections is probably enough for some temporary ventilation IF you are going to put the full vent system in within a month or two.
Bill
My average humidity in the attic is 32% right now, so no, not concerned at about that. It sounds like the insulation I have above my ceilings is my biggest issue. I will rectify that after the roof is installed (since the ridge vent installation may get messy).