What do you make of this roof?
I’ve been asked to work on this house and I’m mulling different ideas to improve the energy efficiency while maintaining the character.
It was built circa 1967. It was built as a four-season house with what passed for insulation in 1967, although for the past 20 years or so it’s been used as a summer cottage. The walls are 2×4 with R13 fiberglass, I’m thinking new windows and continuous exterior insulation and they should be good.
The roof is where I don’t know what to do. It has 4×12 rafters on 48″ centers. Between the rafters are panels of some sort of fiber, about 2-1/2″ thick. Then sheathing over the rafters. It has good overhangs on the eave ends, but no overhang other than the 2×12 trim on the gable ends. I’d like to extend the roof at the gables to have a decent overhang to protect the windows.
Climate zone is 5.
Roof slope is 3:12
Attached is an interior shot.
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This is the gable end.
Eave end, showing overhang. It's hard to make out, but the ceiling material continues through the wall and forms a kind of soffit.
Close-up of the ceiling panel, which is also the only insulation.
We want to get rid of this, while it's an interesting texture it's a pain to live with, there's no way to run wiring through it and no way to patch it if it gets damaged.
Since there's so little insulation in the roof the house gets very hot in summer. I'd like to put R60 or so in the roof. The obvious thing would be an over-roof of some kind, I'm just struggling to figure out how to do it without ending up with a roof that is comically thick, while keeping the beam look on the interior.
Some googling tells me the ceiling panels are probably acoustic wood wool, 2'x4' panels between the rafters. All the panels I've been able to find are only 1" thick; the rafters are definitely 2x12 but only about 9" is showing on the interior so there may be something else up there or a double layer of wood wool.
Wow, I thought you guys would be jumping all over this.
OK, what do you think of this plan: build an over-roof out of 2x6's, on edge, 24" OC, perpendicular to the rafters. They extend out 18" at the gables to create an overhang. The space between the 2x6's is filled with 5-1/2" of polyiso. Between the rafters is another 1" of polyiso and drywall, screwed into the bottoms of the 2x6's with 2" screws.
A total of 6.5" of polyiso give R39, code is R38.
Rakeboards and fascias, which current are 2x12's, become a 2x6 stacked on a 2x12.
Thoughts?
DC,
That sounds like a good plan to me.
As there is presently no overhang on the rakes, and no soffits at the eaves, can you move the fascias up so the bottom is (just about) at the top of the 4"x12"s? That would give you a thinner looking roof.
Do you mean cut the rafter tails?
One of the thoughts I'm toying with is cutting the rafter tails horizontal. I have to measure the current overhang but I think it's 18", with a 3:12 slope that would mean horizontal would be cutting 4-1/2" off the end. So if I add 5-1/2" with an overroof the net is only one inch.
I just have to figure out if that looks right. One benefit: if you look at the first picture, you'll see that the windows go almost to the top of the wall. With the eaves the way they are now, the back of the fascia blocks the view. I'm not sure if we're going to keep the windows but cutting the tails would improve the view.
The house has ocean views but between the siting and the positioning of the windows it's almost entirely obstructed.
DC,
I was suggesting raising the fascia enough that the rafter tails were mostly exposed. Cutting them horizontally would work too.
I had a design client who got together with the builder and decided to raise all the window heads 12". That put them into the soffits, which they then had to slope - but as you say that doesn't solve the problem that you end up looking into the back of the fascia.
I think it would look weird to have the rafter tails exposed.
Pretty normal 70's detail and how my house is done. On my house [Deck House clone] the rafters[4x12 8 foot centers] are cut such that from the 4x4 post they sit on they are horizontal so that the exposed rafter tail is only ~5 inches of a 4x12
Moving the fascia up allows you to not have an 18 inch high fascia when you add 10 inches of foam
[not my house, similar]
After seeing gusfhb's picture I concede it's not as weird as I thought it would look to have the tails of the rafters uncovered, but not sure if it's the look I want.
For the interior side, why not add blocking with 2x2s between the polyiso and interior finish to give yourself a wire chase?
From a stylistic POV, I'd consider doing T&G in a light wood instead of drywall - seems it would match the 1960s modern style of the exposed rafters.
Between the first floor and the second floor are 2x12 joists and then 2x6 tongue and groove forms both the ceiling of the first floor and the floor of the second. So what you propose would be consistent with the look.
It is of course a pain, no place to run electrical or plumbing except in the first floor partition walls. And much of the second floor ended up being covered with carpet or linoleum anyway.
The way to honor the look would be to do as you say and run blocking or strapping and T&G between the rafters. If every few feet one board is held with finish screws instead of nails and the back of the tongue is cut off then you can get in there if needed.
The question is how much depth to the rafters is necessary to keep the look. The rafters are meant to convey a sense of massiveness, that gets lost if too much is hidden. The roof assembly, from interior finish to outer roofing, is going to have a certain thickness, some of that goes above the rafters, some between. The question is finding the balance where the interior look is preserved yet it doesn't look top-heavy from the outside.
Come on a say it, this is a deep energy retrofit and we all know the costs are too high and the benefits are too low to logically do this project. Is the cabin so sentimental that the budget is nearly unlimited?
What are you really saving from this building?
Not the roof, windows, siding, electric, plumbing or HVAC.
The low-cost best result option is knock it down save the beams and install them in the new build as decorations.
Since that will not happen and they want to make a silk purse one step at a time starting with the roof.
Let’s reread my favorite article
https://www.greenbuildingadvisor.com/article/five-cathedral-ceilings-that-work
Since the beams are staying exposed exterior foam seem like the only real option.
Walta
Yeah, the hard part is going to be explaining to the owner that anything that triggers bringing it up to code means new roof, new siding, new windows. Interior stairs and exterior deck aren't to code either.
I have not gotten a new building permit in a number of years, but the only conversation I had was with the fire department needing hardwired smoke detectors, which is a no brainer. Are inspectors enforcing this for real now?
gusfhb,
Here it is dependent on the extent of the renovations. So what they ask for can range from nothing to (almost) up to current code.
The same is true here; the IRC allows for replacing existing elements without having to meet current code. It's only when 50% of a space is redone that you need to meet current codes, and even then there is some latitude.
Here 50% also triggers a review of the septic system. Fun times.
Not sure if R60 is worth it unless you need to get there for code. I would stuff the over-roof with batts and vent it. Around an R30 assembly in zone 5 is good enough, so that would be keeping the existing 2.5" of fiber panels (say R7) and HD 2x6 batts. Lot less work than all that cut and cobble.
I like suggestion of moving the facia up to the over-roof and cutting the bottom of the existing rafter beams.
If it wasn't a wall of glass, I would be temped to lop off the rafter tails, carry the roof air barrier down the walls and nail the rafter tails back up to the bottom of the over-roof.
Except for getting a solid air barrier, not sure if doing much with the walls is worth it. The one issue you'll have is all those nail holes for the existing siding. About the only way to seal that up is new sheathing or peel and stick over the whole thing.
If you really must have more wall R value, this might be a case where Zip R might be worth it as it also seals up the structure.
The place is begging for T&G in the soffits and the ceiling.
Akos,
"The place is begging for T&G in the soffits and the ceiling."
+1.
Agree as well.
The material you see looks to be Tectum decking which is still available. It is wood fibers spun with some sort of binder to make it strong and stable. It seems to be a pretty green product so the idea of tearing it out to go to the landfill for a bunch of foam seems to be a step in the wrong direction.
Why do you need power in the ceiling and are the alternate means to get power to where it is needed like conduit on the existing beams?
If you want to extend or patch you can buy new panels
"Why do you need power in the ceiling ?"
Smoke detectors and lighting. Existing ceiling has fans but I'd like to think with better insulation those won't be necessary.
Thanks for the tip, it seems indeed like it's Tectum panels, perhaps the Finale pattern.
To maintain the feel of heavy timbers inside, ideally they would be at least 1.4 times as high as they are wide, but even 1:1 looks pretty good. A lower ratio makes the beams look flat.
I would taper the outside of the beams; I sometimes do that on new projects, and fancy architects do it all the time.
The vast majority of energy savings is from the first R-38 in a roof. After that the gains taper off substantially. I still do R-60 or more when required, or even more when energy goals require it, or on renovations when it's easy, but I don't worry about reaching R-60 if it's complicated and I don't have to. You could add 4" of exterior polyiso for R-22 (aged) and 3" closed cell foam or polyiso on the interior (R-17, aged). I don't like using foam any more than necessary, but when aesthetics demand it, I'm ok with using it. I think adding 4.75" to the exterior (including new sheathing) would look ok, with a new fascia or just an extra-tall dripedge.
One more creative idea is to step back the rooftop insulation from the perimeter, stopping it at the exterior wall plane, to keep the roof edges skinny. It would probably look weird but it's the kind of thing you sometimes see on high-end architecture, especially European architecture, which the Deck House look always reminds me of anyway.
Michael,
"One more creative idea is to step back the rooftop insulation from the perimeter, stopping it at the exterior wall plane, to keep the roof edges skinny."
That can look really nice, especially with metal roofing.
Another simpler alternative is to extend the new upper portion out past the existing lower one.
I didn't think of that; great idea! Are those your designs?
The extended framing could be visible, as you show, or enclosed for a more planar feeling.
If I was a roofing guy and you showed me that picture, I would charge at least 2x. That is a LOT of fussy work VS a normal roof. The integrated gutters are not helping the cost either.
Someone who can afford that stonework, timberwork, level of design and waterfront lot is probably not particularly price-sensitive.
The first is by Osburn and Clarke, who are known here as "The Cottage Kings". They do uniformly beautiful work, but only for those with deep pockets.
The second pic is from a project by John Pardey. It doesn't look cheap either.
On DC's job it would be pretty simple to extend the over-roof out a bit to reduce the perceived depth of the fascia.
Fair point.
Sometimes people don't realize that a seemingly small change can significantly impact costs.
Simple roof shapes are very easy to cover in metal. Much quicker than shingles. Complicated roofs are very hard, any time you say detail, add $5k.
Akos,
Eye-candy: https://www.osburnclarke.com/work
RE: wiring
One of the things about owning a house without sheetrock ceilings is the difficulty of running wires or plumbing.
I took the occasion of having the roof stripped to run a bit of wiring for ceiling lights etc
I don't know that I would bother creating a chase, but while you are there it is a good idea.
I see people putting framing on the roof and filling it with insulation, and cannot understand it.
Stack the foam up and screw through it. Ladder gable overhangs.
I