Roof ventilation for old house

4460 Views 11 Replies 4 Participants Last post by Gary in WA, May 28, 2016

Dixon12

Discussion Starter · May 25, 2016 (Edited)

I have a 100 year old house in central Indiana. It's below average shape, I think was flipped at least once or spottily repaired here and there. The roof was redone some time ago, although the seller had no info on when or by whom, my guess they did it themselves.

The house is a small, 1.5 story--the second floor is really a finished attic right under the unventilated roof. The actual attic is about 4 feet wide. There is a ridge vent on top, but it seems they only put it up for looks since I couldn't see any openings/holes/gaps from inside the attic. There are no soffits and no inlet vents. Also not sure how much space there is between the roof and the sloped second floor ceiling that's right under the roof to even add insulation. The roof and the second floor get ridiculously hot and I really want to remedy that.

Attached is a pic from the inside, I can take some from outside as well if would help.

What would be a good approach here? I'm waiting on estimates from contractors, but would rather DIY it if possible just because don't think any local roofers would do this for less than $1000, and I could probably do it myself for around $300 in a weekend or two. Was thinking of just removing the ridge vent and cutting the outlet holes then nailing it back on. And for the inlets to use under shingle type of inlet like SmartVent (local stores sell similar products that claim can be easily DIY'ed), or adding vented soffits and drilling vent holes, then adding insulation.

What would be a better option here? Would I need permits and get engineers/architects/inspectors involved?

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Bud9051

· #3 · May 25, 2016

I agree with Greg, you and we are going to need more information.

The sloped ceilings are very difficult to improve, providing code minimum insulation while maintaining a ventilation path above. Even with good ventilation you need good insulation.

More pictures as suggested.

Bud

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Bud9051

· #5 · May 25, 2016

You can open the ridge vent but it will do little good without some low venting.
Options:
1. They make under the shingle vents that could be installed a couple of feet up from the edge.
2. The more common solution would be an unvented roof assemble, called a hot roof.
It is basically an unvented roof assembly.

Here is a related link and on the left side of that article is a longer list of more related articles. Keep you busy

http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-insulated-cathedral-ceiling

Bud

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Bud9051

· #7 · May 25, 2016

Not sure how your overhang is constructed. Those decorative blocks under the eave, are they rafter tails or is there a cavity above them. If there is a cavity above the soffit we see in the picture then either that covering can be opened up to provide ventilation or the edge vents you linked can be used. All providing there is an air path to the upper attic and we still haven't addressed insulation.

Even a well ventilated roof like yours will run 140°, as opposed to 160°. Unless you have a good breeze natural venting just takes the edge off of the temp. Insulation is the bulk of your protection from the heat.

As for what might fit, I don't know what depth you have to work with, but code would be looking for 10" t 12" or r-38.
https://energycode.pnl.gov/EnergyCodeReqs/?state=Indiana

Bud

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Bud9051

· #9 · May 25, 2016

To move forward you really need to know what is in there for insulation. If zero or very little then it will still be hot up there even with a bit of insulation.

now, it is controversial, but in some cases they dense pack those cavities with cellulose. I can try to dig up some of the articles or related discussions. The origin of the method, I believe, is the weatherization assistance program where time is money and they know how to blow cellulose. The result has been many homes insulated that way with no complaints that I've heard. But I'm not at the top of the food chain by any means.

But it is tempting as it isn't that expensive and dense pack does a great. If you consider this approach, the first place to go would to find a company that has been doing it. In Maine they do. Not sure about your location.

They usually have really skinny guys.

Bud

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