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Insulation / Ventilation in Attic


indigo997's Avatar
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05-20-03, 04:39 PM   #1  
indigo997
Insulation / Ventilation in Attic

I tried this in the attic forum and then thought it might fit better here...

I am planning on replacing the roof on my 50-year-old bungalow soon and decided it would be a good time to put in some new insulation in the attic as well. The insulation there is the old loose grey kind. I suppose that I'll have to pull it all out first so that there's a place to put the new insulation between the boards. Some of it has gotten wet in places anyway and probably isn't doing much good.

a) what is the easiest way to remove the old insulation? do I have to pick it all up by hand and bag it?

The second problem is that there's no ventilation in parts of the attic. The second floor of the house is broken up so that there are 5 separate sections of attic that aren't connected. The crawlspace along the top ridge possibly has some ventilation through the gables (at least it looks like this from the outside, but I have no way of getting inside). The other 4 are on the corners of the building (the living area forms a cross in the center of the upstairs) and, although I can see daylight breaking through cracks in places, there is no formal ventilation.
I've read about the importance of ventilation, but it seems weird that the house has gone this long without any.

b)Is there any damage I should look for? How important is it for me to add ventilation now, and what exactly is needed?

 
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05-20-03, 06:43 PM   #2  
Hi indigo,

Ventilation is very important. These closed off areas of your attic should have some sort of ventilation. My own preference is for ridge vent systems when ever possible, for looks, but for this system to work correctly the soffet must also be vented. Since you're having a new roof put on this might be something to think about.

From your description, I'm thinking what you've currently got in the attic is blown in cellulose, rather yucky stuff to be handling, I'd leave it where it is and add your new insulation over it. Are you going with batts or blow in? If the latter I'd suggest using the white glass.

As to damage, if you're having a tear-off done, a good roofer will identify any roof sheeting, weak joists, or soffet & facia boards that need to be replace due to water or other damage. If you need soffet & fascia work done, I'd go with aluminum or vinyl over wood.

Good luck & post back if you have ?'s

 
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05-20-03, 09:48 PM   #3  
indigo997
Thanks for the quick reply!

Some of the old insulation has actually gotten wet from roof leaks and is really matted down so that it's maybe 4 inches deep.

Venting is gonna be tricky because of the way it's cut into the different areas that don't connect. The four corner ones have a low end on the front or back of the house and a high end near the middle. They don't go all the way to the ridge though, and my house isn't really made for soffits.
The very top area is a crawlspace that runs along the ridge, but it has the gable vents at either end so I think it might be ok.

My problem is that I only have money for materials and planned on doing the roofing myself with some help from my dad who is more of a handyman than a skilled craftsperson. I guess I need to get a roofer out for some info anyway.

Thanks.

 
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05-21-03, 09:53 AM   #4  
Edinpitt
I'll stick in my two cents here ...

Seems like lots of houses have lousy ventilation. Some suffer damage as a result. Again, seems like you would get drips on the ceilings if there was a real serious problem, so you may have lucked out. Really good ventilation (perhaps mechanical) should reduce your cooling bills and make that second floor more comfortable.

Since you are re-roofing anyway, maybe for each of the four lower areas you could just put in a roof vent (nothing fancy, just the hole unit with a shroud to keep the rain out). Maybe two each, one low and one high. That should be sufficient for moisture control, and it will do a little for summer heat. Re-roofing should take care of any old leaks, and with better ventilation any moisture that does get in would have a better chance to dry. Meanwhile, the gable vents should be good enough for the top area fpr moisture control.

Seems to me like you could pull the wet, matted down insulation (cellulose) out. If it is thick enough that 4 inches is matted down, it was probably put in recently. The more recently, the more likely that things like a vapor barrier were put in correctly. The bags of cellulose are fairly cheap at my local Lowes, and they rent a blower. I suspect it could be spread by hand, albeit using a lot of time, and someone should chime in here about how the blower fluff it for the proper aeration. Anyway, it is very cost effective, particularly for the do-it-yourselfer. And at least some people adivse against mixing insulation, so you might as well give in and do the inexpensive thing people suggest.

Another suggestion, look into having access cut for your top attic. I'm told it will be messy, plan accordingly.

You might want to have someone with experience take a look around, in terms of looking for damage. Good luck finding someone who won't want to sell you something or some service.
Ed

 
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05-22-03, 06:05 AM   #5  
Ridge vents

The quality/performance of ridge vents varies widely, some aren't much better than no vents according to these tests:

http://headrick.net/hf_ahbu_04.htm

http://www.cor-a-vent.com/airflow.htm

Notice BOTH tests from different manufactures suggest the "filter" type vents tend to be very restrictive and don't achive their rated airflows.
Ridge vents CAN work good IF you get the right type.

Personally I'm a fan of the more open type's of vents such as conventional square roof vents and wind turbines, my attic in Oklahoma is normally rarely exceeds 120F with the wind powered turbines.

 
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05-22-03, 09:15 PM   #6  
I'll agree there are both good & bad ridge vent systems. The key for it to function properly is that it's a component of a complete roof ventilation system. There has to be an equal amount of inflow vents at or near the soffet as there is ftg of ridge vent to exhaust it out.

I'd definitely recommend turbines over static vents, but if cost is an issue, standard sq static vents are the way to go if more vents are called for. Without actually seeing the roof it's hard to determine what ventilation is built in & if additional is actually needed, could be her roof design is adquately vented thru the gable vents, lots of older houses built like that in my area.

With the insulation, if costs is a concern, the blow-in cellulose is the cheapest way to go, a couple of lumber yds in my area allow you to use their blower free when you buy the insulation there. I think Lowes charges, but don't quote me on that.
I've manually installed this stuff, I DO NOT recommend this method. If you do, wear a mask, long sleeves, goggles, the works, very irritating stuff, to me anyways.

If you're going to remove the old wet insulation, use a your dustpan & a garbage bag, regular dustpan will fit between the studs & allow you to scoop it up like a shovel w/o the long handle.

Good luck.

 
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05-27-03, 04:08 PM   #7  
indigo997
Pictures

I put up pictures of the house and part of the attic at http://www.pbase.com/indigo997/gallery/work

I still need to know what to do about ventilating the attic areas. Ridge and soffit vents won't work because of how it is broken into different areas that don't connect.
Thanks for the help.

 
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