I have seriously turned my brain inside out trying to solve the ventilation problem for the attic of our 1914 Craftsman bungalow.
It has no soffits (see photos) and won’t be able to have any. That would ruin the historical design of the structure. But there has to be SOME way to get intake ventilation properly set for this thing.
Complicating the problem is the complexity of the slope of the roof and dormer working against the height of the ceilings inside. Lowering the ceilings could be an option, but with a 6′ 7″ spouse, every inch is a blessing. This network of slopes and inner walls creates a few separate attic spaces and some space that leaves no room at all.
Here are some photos and some dimensions. Take a peek (if only to laugh at me…I most likely deserve it at this point.) My head hurts. Ouch. I need a drink.
So far I have tried:
- to work up calculations to insulate the main open space (below the main ridge and the dormer ridge…they feed into one another) with some rectangular grills set in the wall under the roof for each bay. (Baffling it until the insulation left enough space above it for air flow.)
- This would be hellish work for the whole thing. Might be the only choice for the dormer.
- Perhaps low gable vents for the main ridge space on the north and south? Would snow get in on the north side? (sigh)
- Gable wouldn’t work for the dormer esthetically.
- And how to calculate area? Argh.
So I thought a fresh set of eyes (many, many eyes) and more clever brains than mine could look at this thing. I bow to the master of geometry, algebra, physics and experience though I do not know his or her name yet 🙂
Replies
I may not be understanding something, but the interior is going to have flat, horizontal ceilings on the ceiling joists I see, right? (Not cathedral ceilings following the sloped rafters, leaving what I called ceiling joists exposed?) Can't you put insulation above the ceiling, have screened openings for ventilation at the gable ends and either put in a continuous ridge vent or put in several separate vents in the roof. In other words, the attic would be unheated/cooled space. I think I'm not understanding the situation completely.
I think you've got it right for most of it Dan.
I'm getting confused on my calculations and how to accomplish this because the rooms are made of a combination of exterior walls (easy, fine) and interior walls that hide crawlspaces (hmm...more perplexing).
In other words, when you have a regular second story on a house, the wall is full height all the way around the perimeter, and the roof and attic sit on top of that second story.
This house has a strange second story. The perimeter is of varying heights. But the interior walls are uniform. So, in some places (where there are windows) you have a normal height wall and an attic w/ roof above that. On other walls, you have an interior wall of a normal height which is in front of a crawlspace which is in front of a very short exterior wall.
It's very hard to explain and see in photos. I'll try to draw a 3-D sketch with the roof "off" and post it. Maybe that will help. Even a view of one side cut away might help.
Will you be using the tallest part of the second story for living space or just storage? If it were not in Chicago, (instead, in a warmer clime) I would agree about ventilation not being necessary, but you say you've had ice dams, so I'd think a "cold roof" would be best (ventilation to keep the roof cold and snow from melting to run down and freeze at the eves). If you plan on living in the upper floor too, could you do something akin to scissors trusses--make a sloped ceiling following the rafters, but at a slightly less steep pitch (keep your husband from hitting his head except at the edges) and use ridge vent. Then vent the crawl spaces at their highest walls to the space made between the new ceiling and the old roof? Insulate the walls of the unheated/cooled crawls and insulate the new ceiling and put vapor barriers on the warm side of both. May have to put in little "bullet vents" between rafter tails at the low ends of the crawl spaces on the outside wall to vent the crawls spaces. Then air would flow from these low bullet vents into the whole crawl space, then out the vents at their highest walls, into the space between insulated ceiling and rafters of center space and out the ridge vent. Good luck.
In any case, sounds like just about anything you do will be better than what was there! The house I live in was owned by what I call a "Wyle E. Coyote, Super Genius"-type, so I am confident that anything I do here is better than what he did. Maybe I'm delusional, but I'm happy.
Will you be using the tallest part of the second story for living space or just storage?
Well, that depends on where you are standing <grin> Because the roof slopes, some of that attic will just be attic (no storage up there...we've got pretty good storage in the basement and the "back attic".) In the middle of the house up there and the dormer, there is plenty of attic space above the living space (about 3' feet). On the sides--because the roof slopes-- to maintain an 8' ceiling, there is very little space above the living space, kinda like a cathedral ceiling would be. Enough space for 2" ventilation and the insulation and that's it. And behind those side walls are the crawl spaces which are too short for us to us as living space. (Back of the house for storage, it's a pretty big crawl space we call the "back attic". Has its own little door scaled down to match the rest of the doors. Front of the house on either side of the dormer, that space is just sealed off. Would love to use it as storage, but...one side has the house side of the chimney. The other side, well, maybe some built in drawers there if anything, but I'd like to seal it up so I don't have to ventilate that space separately. Because, oh, the PITA of putting vents in such a small space.
Drilling through 90 years of stucco and very hard wood will be tough enough. And it's "stucco on stucco". They put an extra thick second coat on there sometime between 1930 and 1960.
If you plan on living in the upper floor too, could you do something akin to scissors trusses--make a sloped ceiling following the rafters, but at a slightly less steep pitch (keep your husband from hitting his head except at the edges) and use ridge vent. Then vent the crawl spaces at their highest walls to the space made between the new ceiling and the old roof? Insulate the walls of the unheated/cooled crawls and insulate the new ceiling and put vapor barriers on the warm side of both. May have to put in little "bullet vents" between rafter tails at the low ends of the crawl spaces on the outside wall to vent the crawls spaces. Then air would flow from these low bullet vents into the whole crawl space, then out the vents at their highest walls, into the space between insulated ceiling and rafters of center space and out the ridge vent. Good luck.
That's a nice detailed piece of advice. I think those bullet vents between the crawl space and main attic above might work nicely, come to think of it. Thanks!
In any case, sounds like just about anything you do will be better than what was there! The house I live in was owned by what I call a "Wyle E. Coyote, Super Genius"-type, so I am confident that anything I do here is better than what he did. Maybe I'm delusional, but I'm happy.
Oh, I think I am way delusional. :) Whenever I hit a problem like this, I just keep thinking..."Well, she's lasted this long. She's lasted this long."
Our previous owner and her favorite cheap labor all around "handyperson" "fixed up" the house for sale in the last 3-4 years (he did masonry! plumbing! electricity! carpentry! All poorly...I think he knew your Wyle E. pal. They definitely both shopped at Acme together) . I wish they'd never touched it. Everything that they've done we've had to undo, then redo. Makes for WAY more work than if they had just left it alone.
I've seen muddling before, but we've been calling this one mangled. :)
Why are you wanting to add this venting to a house of this age?
Is this an attempt to deal with a moisture problem in the attic?
Or for some imaginary shingle warranty?
Why are you making your head hurt? There must be a reason, but you didn't let it out.
Joe H
Good question :)
Maybe we don't! We don't know how the house was shingled in 1914. The house used to be heated with a coal boiler firing steam heat, had a lot of air leaks, etc. etc.
Over the years, the old owner changed some things. Gas boiler verus coal. They threw a lot of insulation stacked on insulation up there that we had to completely get rid of because a few generations of raccoons used it for a litter box (balsam wool, covered by stacks of newspaper, covered by "bunches instead of rolls" of fiberglass.) Then we found the water damage and mold from the years that they let the roof leak and never fixed it. So the ceiling had to come out...then the walls up there. (I was in tears and in denial. I love old plaster. But mold is, well, mold. And raccoon souvenirs had collected in the walls too...balloon framing.
They had the roof redone 5-7 years ago with asphalt shingles. Put a whole house fan in (poorly) and some mushroom vents (poorly). No intake, just exhaust. Over the winter we noticed that we are getting a fair amount of ice damning as the warm air from the steam heated house made it's way to the attic and melted the snow on the ridge. It melted into the snow on the overhang, re-froze and put a lot of weight on the gutters (as well as the edge of the roof.)
If there is some way to re-insulate the attic and avoid ventilation, I am all ears. :)
Edited 7/2/2004 10:32 pm ET by jmo
Edited 7/2/2004 10:32 pm ET by jmo
The ballon framing was intended to be the ventilation...
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming.... WOW!!! What a Ride!
I know. Unfortunately, balloon framing extends from the basement to the attic and any warm air in the basement (stoopid oversized furnace, we're working on it...) goes right up to the...you guessed it...the attic.
Plus, now we've gotta put those fireblocks in for safety reasons.
And I would guess the shingles used to be shakes. This roof wouldn't hold slate up.
So we're sealing everything up as tight as we can. But it's an old house. :) So my money is on some kind of ventilation.
Which brings us back to...venting the bays for the dormer, I guess. And gable venting the main attic. And I guess we'll try to seal up the crawl spaces as best we can.
Just wanted to know if I was heading in the right direction or if there was a better way.
Seems so.
Venying the gables also appears to be about the best way to vent. Least amount of hassel..
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming.... WOW!!! What a Ride!
>>So we're sealing everything up as tight as we can. But it's an old house. :) So my money is on some kind of ventilation.
I thought you wanted circulation, why are you trying to seal everything up?
There is something to be said for some old structures that sort of vent themselves with out all the arguable 'science' that we now have on hand.
I for one don't like all sealed up tight gagging on stale air, or a wind tunnel either. If you aren't getting condensation or ice dams then what is the problem. Don't make one where it didn't exist before.
EricEvery once in a while, something goes right!
Sorry, thought I mentioned earlier that we are getting ice damns. That's what led me to get on this ventilation kick in the first place. Which is especially hard on the edges of a bungalow roof and its gutters.
At the very edges of the roof, the ice is backing up under the shingles a bit too. That's something I'd rather not see either.
Bungalow roofs are beautiful....and strange. Especially where they hang off into space on their rafter tails and you can see the underside. Gorgeous look (once everything is properly stripped, primed and repainted. )
I had noticed quite a bit of rust on the roofing nails inside of the attic. But that doesn't surprise me since a lot of the warm, moist air from the house in winter is leaking into the attic.
I'm a big fan of fresh air too. Would love to not have to vent or seal up the ceilings so tightly. But ice damns, condensation and gas bills...that is serious.
I know I can run the new Hi Veloc system in the winter to freshen air inside of the house if I need to. Between the dog and us, we aren't staying shut up in here all day with nothing opening and closing. And, even though we've cleaned up the original windows, I know that nothing in the walls is THAT tight. Installed some badly needed (never had 'em) ventilation fans for the bathrooms and kitchen. This house will never be hermetically sealed :) Nor should it be. But I'd like to keep warm, moist air out of that attic.
The PO has an old (improperly installed) "whole house fan" up on the roof that concerns me as well. When it's operating, it's trying to pull air up and out but there are no intake vents for the attic. Never ran across a whole house fan...never wanted one. Not sure if I should disable it or what.
Lots of possibles, spray it with foam is the fastest expensivest.
The trick is to keep the heated, humid air that is in your house in your living space. You paid to heat it, you want to keep it, not use it to melt the snow.
Vents aren't the answer, or, it can be done without the vents by sealing the ceiling plane.
Joe H
This has been discussed dozens of times, the Vent Wars from 98/99 on.
There used to be lots of info in the archives, I don't know what's there now, but if you search for venting, baloon framing, vapor barrier ect you will find enff reading for the weekend.
Joe H
Joe, Joe. :) I've read through the vent wars. I think this puppy is going to need to be vented, if only because she would be durned near impossible to seal.
It's the wacky rooflines that are stumping me. First time I gotta house with this kinda roof. And I couldn't find anything like it in the archives. Any of the others I worked on with the family and pals have been pretty straightforward. But this baby is my own and she's a pretty Craftsman gal and, as much as I grumble about her, I want to treat her right.
Plus, she was mistreated pretty badly for a long time. For example, she had concrete stuffed in between her bricks a few years back instead of mortar (no LIME!) because the PO's granddaughter wanted to wring as much cash out of her as possible. I sweated the removal of the concrete and the right mortar mix...I'm sweatin' it all. But since the walls are opened up, we are getting HVelo Air installed and I'm crawling over every inch of it. Three beautiful 90 year old windows had been chopped in half to accomodate enormous (now non-functioning) 1970's window A/C units. Beat the streets to find the craftsman working out of his garage who could rebuild those. Because the rest were still beautiful. So we'll update her a little bit. Tracked down one of the original guys who worked with the Unico outfit. We planned it out to the inch. 'Cause I can't give up this fun steam heat (like tuning a cello), cool less humid air is critical for Chicago summers, and my kids will like it better when I pass this house along to them. (And with forced air we would have had to create lots and lots of soffits...wreck the profile of the original room designs.)
Yes, I am a bit of a nut about getting the systems right to last her another 90, even if I won't be here to celebrate her 180th. I love watching craftspeople work and I love to work at that level the little I know how. Ask my husband, it is an attribute that he finds lovable, most of the time. (I know, he's nuts too.)
Sorry I haven't been on for awhile fellas (doffs her hat to Piff, CAG, TEC, CloudHidden, Luka, Andy, Pino, Jeff, Pi...drat. I know I am forgetting someone.) Anyhoo, house + gnarly health problems these last 6 months = less Breaktime fun. I miss y'all. You KNOW there are beers in CHicago with people's names on them. We wouldn't make you work. The sailboat's in this summer (dangle, dangle...courtesy of Aaron's grandfather, the lovely old salt. And she's got quite a bit of teak on her for those of you who can't get away from wood for even one second...)
Edited 7/3/2004 2:29 am ET by jmo
It looks like you could drill holes in the area between the rafters and install circular vents, the install a ridge vent.
With the skip sheathing up there the original roof was probably cut cedar shingles (possibly shakes - remotely possible slate, but very unlikely based on the apparent structure.)
Don't worry about the venting ratios; I've read that some guy made them up years ago and I have not seen any relationship between vent size ratios and actual performance.
To avoid the ice damming, the most important thing to do is keep the heat in the house and out of the attic. saves money, too.
Vent as well as you can
Consider talking to an experienced home ionspector with >5 years experience to see what works and doesn't work in your area.
"It is as hard for the good to suspect evil, as it is for the bad to suspect good."
-- Marcus Tullius Cicero, statesman, orator, writer (106-43 BCE)