Fixing a hot attic

[firecadet613]

Those air baffles look fairly narrow. Your truss spacing is 24", correct?

Is the underside of your decking shaggy and de-laminating or is that an optical illusion of the picture?

Underside of the decking is solid, just a bad picture. Had to have some mold remediation done when we bought the place, so some remnants of that.

Is that yellow insulation tucked around the baffles OK? Should the soffit vents be open?

 

[Jaybird1980]

Thanks! I jumped up in the attic and the soffits do appear to be blocked a bit (maybe/maybe not - you decide). Good to hear I won't need to install gable vents (although I did pick up a few for my barn - look for a thread on where to place them soon).

Plenty of insulation though and a junction box is already there I can tap into.

@Jaybird1980 funny, the fan you linked to is one I found earlier today. They also have a high efficiency one for double the price.

Let me know your thoughts on these pics...

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Those soffits baffles are open enough. Sure they are not exactly right but they do enough to let air though. As long as those are on the front and back I say you have enough intake air.

The yellow insulation is fine, it's what is keeping blow in from spilling into the actual soffit area. The air flows through the baffle itself.

 

[JettaKnight]

Be sure that bathroom vents, stove hood, and dryer vents actually vent to outside. I had a house where all of them were vented into the attic, this causes excess moisture to get trapped in the attic.

Same here.

Had to replace a lot of plywood decking.

Side question - anyone ever install a whole house fan? I like to keep the bedroom windows open at night to hear the water garden's water stream, and I'd like to harness all that night time cool air.

 

[Jaybird1980]

It is nice to see they raised your attic access, that will make it easy to insulate. Get some insulation board and go to work.

 

[firecadet613]

Those soffits baffles are open enough. Sure they are not exactly right but they do enough to let air though. As long as those are on the front and back I say you have enough intake air.

The yellow insulation is fine, it's what is keeping blow in from spilling into the actual soffit area. The air flows through the baffle itself.

Thanks! Looks like I just need to grab a fan and I'll be set. I'll go ahead and get two, might as well get the attic over the garage done while I'm at it.

 

[JettaKnight]

Wow. Talk about half a**ed. Am I seeing 16" soffit vents on a 24" rafters?
Those are the things I was talking about. They are supposed to staple to the rafters and direct the heat directly to a ridge vent.

You must be new to home construction.

*If* the run is short, i.e. not running over a cathedral ceiling, it'll be ok, but not ideal.

 

[BigBoxaJunk]

My house was built in '98 with the same venting system you have on yours, and the styrofoam soffit vent things in the attic also look the same. I had poor ventilation as well, with a hot attic in summer and moisture in the attic in the winter. I had the added problem that, on a few occasions I would get fine blowing snow to get into my roof vents, just enough to melt and stain the ceiling. So, I covered the outside of the roof vents and installed an attic fan with thermostat/humidistat. That cured all of my problems. I also had added timers to both bathroom vent fans to help keep moisture down, and I never had moisture in the attic after that. You could barely hear when the fan was running, and I don't think it made a big difference on my electric bills.

Fast-forward to two years ago and we had a new roof put on. Took out the attic fan, removed the roof vents, and installed a ridge vent system. Now, I'm pretty sure that its better, even without the fan. Also my garage stays way cooler now in the summer.

 

[Ark]

Wow. Talk about half a**ed. Am I seeing 16" soffit vents on a 24" rafters?
Those are the things I was talking about. They are supposed to staple to the rafters and direct the heat directly to a ridge vent.

Maybe some people get away with it but this is definitely my reaction too. 24" rafter vents are like $2 each. Personally I'd lose the rolled insulation, retrofit with proper size baffles, and ridge vent. But, I'm biased towards "all the freaking ventilation there is no such thing as too ventilated".

Much like a car engine, intake must match exhaust. Throwing a fan in may help, but only if incoming air is unrestricted.

 

[firecadet613]

My house was built in '98 with the same venting system you have on yours, and the styrofoam soffit vent things in the attic also look the same. I had poor ventilation as well, with a hot attic in summer and moisture in the attic in the winter. I had the added problem that, on a few occasions I would get fine blowing snow to get into my roof vents, just enough to melt and stain the ceiling. So, I covered the outside of the roof vents and installed an attic fan with thermostat/humidistat. That cured all of my problems. I also had added timers to both bathroom vent fans to help keep moisture down, and I never had moisture in the attic after that. You could barely hear when the fan was running, and I don't think it made a big difference on my electric bills.

Fast-forward to two years ago and we had a new roof put on. Took out the attic fan, removed the roof vents, and installed a ridge vent system. Now, I'm pretty sure that its better, even without the fan. Also my garage stays way cooler now in the summer.

Great feedback, thanks!

Sounds like the fan will cure the issue, which is what I wanted to hear.

 

[firecadet613]

Maybe some people get away with it but this is definitely my reaction too. 24" rafter vents are like $2 each. Personally I'd lose the rolled insulation, retrofit with proper size baffles, and ridge vent. But, I'm biased towards "all the freaking ventilation there is no such thing as too ventilated".

Much like a car engine, intake must match exhaust. Throwing a fan in may help, but only if incoming air is unrestricted.

Agreed. But with a brand new roof, not going to cut into it and replace the vents with ridge vents. I do have ridge vents on the shed and it stays cool in there!

If only I could put ridge vents on the barn...

Good info on the rafter vents, that may be a project when I get everything else done...

 

[dudley0]

Do not remove the rolled insulation tucked into the foam. Even if you replace the foam with 24" wide stuff put the fiberglass back in there.

First of all it keeps the blown stuff from getting into your soffits. Second it helps with the insulating value right at the top of the wall. If you drop the foam down to the top plate you could see a nice line outside on the roof in winter.

Determine what the soffit vents look like as in how much airflow will they allow. If they aren't continuous or close to it then switching to the 24" wide foam isn't going to help much. When in the attic during the day turn out the light source and look down the slope of the roof into the foam baffles. Do you see light at all? If not then maybe pop a couple pieces of soffit and see what they covered. I have seen solid ply soffit covered with pretty vented vinyl more than once. I have also seen where they ran decking up the wall between the trusses, thus blocking airflow.

 

[firecadet613]

I can see light, so I think they are good.

Fan is in, super easy to enlarge one of the vent holes and wire up the fan.

And since I can jump on the garage roof, then the second story roof, no need for a huge ladder.

What temperature does everyone have theirs set to come on at?

 

[jaymark6655]

I can see light, so I think they are good.

Fan is in, super easy to enlarge one of the vent holes and wire up the fan.

And since I can jump on the garage roof, then the second story roof, no need for a huge ladder.

What temperature does everyone have theirs set to come on at?

I have mine set to come on at 100. Any lower than that and I think that it will run too much, any higher and it gets too hot and humid. I think I had looked it up and determined that 100 would help prolong the life of my roof.

I put my own fan in. When I cut the hole in the roof, the outside temp was about 80-85 and nearly 100% humidity. I was pouring sweat on top of the roof, as soon as the piece dropped out of the hole and blast of extremely hot air came blasting through, hitting me in the face. I almost passed out and fell over. Immediately started tossing tools into the front yard and slide down 12/12 roof toward the ladder, hoping I would be able to stop and not miss the ladder entirely. Somehow climbed down the ladder, crawled into the house (I could no longer stand), into the shower with cloths still on, reached up and turned the cold water on. I am really thankful I didn't go of the back side of the house where I was cutting the hole, its a 20+ foot drop.

Do not envy anyone doing this job this time of year, try to do it in the morning, not in the evening.

 

[firecadet613]

I have mine set to come on at 100. Any lower than that and I think that it will run too much, any higher and it gets too hot and humid. I think I had looked it up and determined that 100 would help prolong the life of my roof.

I put my own fan in. When I cut the hole in the roof, the outside temp was about 80-85 and nearly 100% humidity. I was pouring sweat on top of the roof, as soon as the piece dropped out of the hole and blast of extremely hot air came blasting through, hitting me in the face. I almost passed out and fell over. Immediately started tossing tools into the front yard and slide down 12/12 roof toward the ladder, hoping I would be able to stop and not miss the ladder entirely. Somehow climbed down the ladder, crawled into the house (I could no longer stand), into the shower with cloths still on, reached up and turned the cold water on. I am really thankful I didn't go of the back side of the house where I was cutting the hole, its a 20+ foot drop.

Do not envy anyone doing this job this time of year, try to do it in the morning, not in the evening.

Thanks, that's what I set it to as well.

It was 68° here when I did the project so not too bad, a bit surprised how much hot air kept pouring out once I took the existing vent off, given there are 5 vents up there.

 

[Jaybird1980]

I can see light, so I think they are good.

Fan is in, super easy to enlarge one of the vent holes and wire up the fan.

And since I can jump on the garage roof, then the second story roof, no need for a huge ladder.

What temperature does everyone have theirs set to come on at?

I had mine set at 110, I was told to always make sure it is set higher than your highest possible ambient temp. I figured we have seen 100 on occasion so I went with 110.

Not sure if 10 degrees really gave the motor a rest on the hot days though.

 

[Jaybird1980]

Thanks, that's what I set it to as well.

68 here when I did the project so not too bad, a bit surprised how much hot air kept pouring out once I took the existing vent off, given there are 5 vents up there.

Were the other vents open, I have seen them plugged up with debris.

Wasp nests, tree sheddings, insects etc.

 

[firecadet613]

Were the other vents open, I have seen them plugged up with debris.

Wasp nests, tree sheddings, insects etc.

All good, no blockages. There was air coming out of them all before I removed it, my guess is it all started to come out that hole.