Attic Venting, old house no vents installed


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Old 02-02-11, 01:58 PM
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Attic Venting, old house no vents installed

Hey guys this spring I am going to put venting in my attic since there's none. I need a couple of pointers.

Its a old house approx. 90 years old story and a half. No roof vents, metal soffit has the vents but the installers never cut the holes for the intakes in the soffit.

Ok I've tried in the past to pull out the soffit pieces but no luck, could'nt I just cut a square out of the metal soffit cut my wood soffit and then replace with a square undereve vent? Seems the easiest.

As for the roof I figured three roof vents on both sides since the attic is finished in the middle.
 
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Old 02-02-11, 04:11 PM
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Yes you can do what you suggest for the soffit vents. If you will be happy with the looks i see no problem with that approach.
For the roof I am partial to ridge vents myself. Cutting a slot out of the peak of the roof would be much easier I would think than 6 holes.
Do you know if the soffit is even open to the attic? It is possible that it is blocked off either by boards or insulation. That is something you will need to check if you have not already looked.
 
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Old 02-02-11, 06:35 PM
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I don't think a ridge vent would work, because the attic is finished in the middle and the drywall runs right to the rafters and its blocked off with insulation and vapor barrier.

If the soffit is blocked off is there a way around it? I will have to look at it, is there a way to tell if its blocked off from the inside? I know that there is insulation laid in between the joists.
 
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Old 02-21-11, 08:09 AM
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If no one installed foam baffles, insulation then the sheetrock, and there's no soffit vents then no form of roof venting is going to do anything.
If someone install the insulation tight to the roof sheathing it's going to super heat the shingles and lower there life by at least 5 years.
What we do in most cases with a cathedrial ceiling is add 2 X 2's to the rafters, add foam baffles then R-13 at least insulation. Then use a ridge vent.
If the soffit material they used is just reguler triple 3 vented soffit you have to start on the end when tring to get it down. Once one piece comes out you can get at the nails holding the next one. You may have to try one end and then try the other end to figure out with way they ran it when installing it.
Once it''s out you can knock out the blocking or use a 3" self feeding auger bit with a right angle drill to bore the vent holes.
 
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Old 02-22-11, 07:05 AM
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What are my options?

So I did some exploring while it was alittle warmer. I took a piece of the metal soffit out to find that it is in fact solid wood.

What are my options? Should I try to cut access holes in the soffit and then drill holes through the plate? Seems to be alot of work.

Or should I install gable vents on the back of my house?
 
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Old 02-22-11, 07:38 AM
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Yes you will need to cut holes in the soffit. Here is a good thing to look at about venting your attic. Hopefully it will help.
How to Install an Attic Vent | DoItYourself.com
You do not drill holes in the plate.
 
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Old 02-22-11, 08:29 AM
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Thanks for the link. But my attic is different from the animation. The one thing that is different is there is a board that runs the length of the house that is tight to the roof and nailed to the plate. And the rafters tie into that board. In the animation where the place the baffle to hold the insulation down thats where the board is so if you were looking down my house it would look like this

this board is tight to the roof
______
|_____|
/__________| |

soffit
 
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Old 02-22-11, 10:02 AM
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[IMG][/IMG]


sorry that its so big.
 
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Old 02-22-11, 02:40 PM
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First let's see if the image loads...


I guess that the red part I added is tails to tie the plywood soffit onto.
Would it be possible to drill 3 inch holes every 6 foot in the plate to allow airflow as indicated by the yellow paint? This board is not as structural as the top plate.
The smaller green line indicates a airflow baffle so the insulation cannot block the air. You would have to block the floor joist and from the floor to the rafters as shown by the gray color to ensure the insulation does not block the airflow.
 
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Old 02-22-11, 03:14 PM
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Thats how I was thinking of doing it, but it helps to see the airflow, it would be possible to every 6 foot just alot of work.

The solid wood isn't plywood its actually wood slats, like a hardwood floor. Just one question I had, you said "I guess that the red part I added is tails to tie the plywood soffit onto" what does that mean? Should I cut pieces of wood to create a "bay" in the soffit, where the vents are going to be?
 
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Old 02-22-11, 04:27 PM
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Because added vents would still have a restricted air flow to the baffles, I would use this; Cor-A-Vent : IN-Vent

A 3" hole with a screen is only 2-1/2 sq.in.NFVA; Lomanco Product Lines You would need to drill them end to end with 1" space between holes to get the required 9sq.in. NFVA per lineal foot! Easier the pull the soffit, cut a 3" slot the length, add continuous vented metal and shorten-then re-install the existing soffit. Of course you still have the constricted air path to the baffles....

Gable vents are not nearly as efficient, but may have to work if not using either suggested method. Certain locations don't require attic ventilation, and color of roof is 20-30% of the cooling effect for the roofing shingles--- venting is only 2-3%; http://www.fpl.fs.fed.us/documnts/pdf2002/rose02a.pdf

http://www.fpl.fs.fed.us/documnts/pdf1999/tenwo99a.pdf

Gary
 
 

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