How hot is too hot?

[Ben H]

This may sound a bit stupid, but when can you tell when an attic is WAY to hot...or hotter than it "should be?"

I had a home today, 78 outside in the sun. It was 148 in the attic. Doesn't that seem a bit much to you guys? I did notice that the blown in insulation was right up o the ends of the rafters, so I'll be writing lack of ventalation up.

[Mark P]

Sure sounds to damn hot to me. Seems I've read or heard that a properly vent attic should be close to the outside temp.

[Marc]

On naturally vented attics, heat is the engine which lifts air to the vent openings at the top, which draws in fresh air at the soffits. If the attic isn't hot, this won't happen.

148 is hot! I recall becoming curious and measuring the temperature of an attic in which I was installing an HVAC duct to a laundry room. It was 141. I couldn't stay in there more than 5 minutes at a time. It took quite a while to do the job.

Marc

[caryseidner]

I've heard that too Mark.

[Tim Maxwell]

I get attics that hot all the time.......in August.

I've only seen 125 or so so far this spring.

[kurt]

I've seen 135 a few times. 148 is really hot.

[Tom Raymond]

Dammit! Now I gotta go put a remote read thermometer in my attic. I know it gets really hot up there, but I've never actually measured it.

Tom

[Nolan Kienitz]

Well ... this past summer (DFW) I had a few attics that were near 160-degrees!!

Did you notice any ventilation baffles to allow air flow from eaves (soffit vents) and into/through attic?

[Tim Maxwell]

153 was my highest reading. It was last summer. Direct sun, black shingles, hot humid day.

[randynavarro]

If it was a dark or near black roof, that radiant heat can overcome any natural draft induced by passive ventilation.

[msteger]

In my area, I'd call out 120 degs or more in the attic, unless it was 95 degs outside. If I measured that, I'd expect to see blocked soffits or a problem with the ridge venting or something. I once measured a 145 deg attic.

[John Dirks Jr]

I suspect that everyone is measuring the temp with IR thermometers.

Keep in mind that when you point it at whatever, you're taking the temp reading of that particular surface. Point it at the sheathing and you can expect to get a high reading since it is getting the radiant heat from the sun plus the build up in the attic space. The temp of that sheathing is not necessarily the temp of the attic air.

[charlieb]

140 =/- in the summer

digital thermometer

[Ben H]

I suspect that everyone is measuring the temp with IR thermometers.

Keep in mind that when you point it at whatever, you're taking the temp reading of that particular surface. Point it at the sheathing and you can expect to get a high reading since it is getting the radiant heat from the sun plus the build up in the attic space. The temp of that sheathing is not necessarily the temp of the attic air.

True. Thats why I took readings on the floor, rafters, insulation, etc... They where all about 3 +/- of each other.

[Rob Amaral]

FTR, I've found around 140 deg F in attics around Boston in summer..

[SamNorwich]

I have seen where over insulation has blocked attic ventilation. This is dangerous, not only for heat, but for moisture buildup and even release of gases. It is best to have a well ventilated attic and your inspection report should site making improvements in that area.

Sam N

Indianapolis Real Estate Inspector

[rickywells]

Talking about HOT!!!

Inspecting Attics in the deserts of Arizona are just that "HOT"

In the summer months of July and August when ambient temps are 110-115 degrees, Attic spaces are always 140-150 degrees.

The attic spaces that have Thermal Shield or Solar Shield on the underside of the decking are much cooler than the normal attic space so that stuff does work as far as keeping the attic space cooler (approx 30-40 degrees difference).

[robert1966]

I see 125 when it is 90-95 outside here in Houston, with tech sheild that normally drops to about 95-98 degrees.

[hausdok]

I didn't do an attic today because of the heat. Just under 140°

Normally, I don't worry about attic heat because I can get in and out pretty fast; however, today's inspection had 12-inches of clearance from the top of the ceiling joists to the underside of the rafters where they were nailed to the ridge board. I normally do those, because I only need 10-inches of clearance to get in; however, it was tight enough to slow me way down and the house was large enough that I probably would have been in there on my belly for 45-minutes; too long in a 140° attic. By the time that I'd gotten in and worked my way the entire length of that space and gotten turned around, I probably would have passed out from heat exhaustion. The thought of being the guy that they talk about the 911 guys rescuing can be a powerful motivation damper.

ONE TEAM - ONE FIGHT!!!

Mike

[Vicbowling]

Talking about HOT!!!

Inspecting Attics in the deserts of Arizona are just that "HOT"

In the summer months of July and August when ambient temps are 110-115 degrees, Attic spaces are always 140-150 degrees.

The attic spaces that have Thermal Shield or Solar Shield on the underside of the decking are much cooler than the normal attic space so that stuff does work as far as keeping the attic space cooler (approx 30-40 degrees difference).

That does seem really HOT!! We did some spray foam insulation work on my dad's attic and we didn't realize we'd blocked a vent.. So it got miserably hot this summer, way worse than it's ever been! Before he went and bought AC we fixed the vents up and what a difference! If he'd been in Arizona we'd understand but he's up in Washington so we knew straight off that something was up.

It's a bit embarrassing to muck up something like that but at least we solved it before a different inspector saw it.. Oh the irony and humiliation that would have been.. [:-sour]

[Douglas Hansen]

A home inspector in Las Vegas died on the job in July 2004 in a hot attic. He was a highly qualified, well-trained, and sober person, in good physical shape in his late 30's. The last photo on his camera was the one he took from the attic entrance. It appears that he fainted from the heat when he first stood up inside the attic, fell backwards, and landed on his head on the garage slab. He was alone at the inspection.

The company that employed him holds weekly safety meetings, and after the accident, they changed their policy on attic inspections.

Be careful out there...

Douglas Hansen

[Bain]

A home inspector in Las Vegas died on the job in July 2004 in a hot attic. He was a highly qualified, well-trained, and sober person, in good physical shape in his late 30's. The last photo on his camera was the one he took from the attic entrance. It appears that he fainted from the heat when he first stood up inside the attic, fell backwards, and landed on his head on the garage slab. He was alone at the inspection.

The company that employed him holds weekly safety meetings, and after the accident, they changed their policy on attic inspections.

Be careful out there...

Douglas Hansen

There have been times, especially when negotiating an attic that contains trusses, that I've been dead certain I would pass out, have a stroke, or suffer some other paroxysm before making it back to the scuttlehole. It hasn't happened yet, but you're right. It's silly to take unnecessary risks.

[Denray]

I backed into a crawl space once. All the vents were insulated over. I turned around and 75% of the area was a swamp. Strange smell. I could see mysef passing out on the back side. Speaking of smelling things I figured they weren't going to pay me either. Supposed to be run thru some kind of Indian welfare deal. I asked for payment before I would write it up. Never happened. At least I didn't die for free.

[Jack Ahern]

Last inspection in July. 142F digital --attic in Needham, Ma. Older house--no visible vents in roof.[:-banghea