VERY HOT UPSTAIRS AND ATTIC IN THE SUMMER

[Bob moran]

My son mistakenly purchased a flip without having me take a look first. The upstairs and attic are way too in the summer. I have an AC guy coming out to check the system but already know the attic has some issues. There is not enough insulation that we will address. The house is probably from the 60's or so. None of the houses in the neighborhood (or his) have soffit vents. He has a very small (maybe 4-6") soffit. He has a gable vent with a non working (or mounted) powered fan. I can mount this and ensure it works. From what I have read it was not unusual for houses from this era to be built with no soffit vent.  Without a soffit vent will I be wasting my time getting the gable vent operational. Should I in fact be looking to replace the solid soffit (as small as it is) with a vented soffit? Bottom line is any advise you can give me to get his attic vented properly would be appreciated.  Thanks

[Marc]

If the gables are vented, you don't need soffit vents.

[Tom Raymond]

I agree with Marc, but, the gable vents may need to be cleaned and worse case may be too small. Address the insulation first and see where that gets you. Blown cellulose is an excellent bang for your buck.

[Erby]

Personally, I'd throw on a ridge vent and add soffit vents.  Then close off the gable vents.

 

[Les]

13 minutes ago, Erby said:

Personally, I'd throw on a ridge vent and add soffit vents.  Then close off the gable vents.

 

He said this is a flip and you should not do anythi

ng right.

[Mike Lamb]

If there is not a lot of blackness underneath the roof sheathing in the attic then the gable vents are doing their job. That means the attic is being ventilated adequately. Don't mess with something that is working.

Assuming this, clean the gable vents and blow in a minimum of 14 inch cellulose insulation across the attic floor. This will keep a naturally hot attic from radiating down through the ceiling in summer making the AC work harder, and help keep warm air from rising into the attic in winter. I think that's all you want.

Trying to get balanced heating and cooling with a one zone HVAC is pretty much impossible. There are thousands of homes in Chicago without soffit vents. My experience is gable vents work great. That said, I don't know what part of the country you are in.

I think, if the insulation/sealing the attic floor is good then attic fans are typically a waste of money.

[BADAIR]

i personally stay away from prescribing any retrofit-upgrade-alteration to properties i've not inspected & really have no knowledge of beyond that of the op w/o any pix

numerous prospective clients actually send me pix & my standard reply is "unless i can see the current conditions in person i cannot factually comment any further, if you need someone to offsite evaluate i am not your inspector"

Edited October 23, 2020 by BADAIR

[Jim Baird]

I often see gable ends vents with ordinary screen wire on them.  Minimum mesh for roof vents is 1/8".  It allows max vent area while still keeping bugs out.  Old screen wire can get mighty clogged with dust.

[Bob moran]

Thank you for all the replies

[TimK]

For what it's worth, the various forms of venting can all work, or not.

I was a roofing project manager (PM) for a Design/Build contractor (thrown in to the deep end with no training - yay!). This was added on top of my Home Performance PM job duties. This was in Bend Oregon right after we'd had a winter that led to a lot of houses having destructive ice dam issues. There was 3-1/2 feet of layered snow and frozen rain on my roof that had to be shoveled off - that happened in 5 storms over the course of 1-1/2 weeks - oh joy! The houses that I saw the least damage in were the older houses with gable vents. The ridge vents were sealed up with the above-mentioned snow/ice layer cake. There's a fair amount of wind here regularly, which is my best guess as to why the gable vented houses worked better.

The GAF roofing materials representative argued the company line that we had to close the gable vents - because they were neither high or low vents. My theory is that it doesn't matter (gable vents don't care what you call 'em) if air moves through the attic regularly - and I argued with the GAF rep endlessly. I understand the idea, but our local experience said that the gables were just fine. If you have to have the roof shoveled in the winters when we have those kinds of storm, it's not exactly beneficial, especially if the occupants are elderly, or if the rooves are steep or 2-3 stories high or otherwise difficult to access. Bottom line, you need airflow under the sheathing, by whatever means works in your situation.

Building science is a discipline that needs to be applied with thought to the individual scenario.