I have an old farmhouse that recently had a fire.  Kitchen gutted, dining room badly damaged, rest of house has LOTS of Smoke and water damage.
Exterior is intact, and you can't tell there was a fire.  Very little structural damage.
The house was pretty much uninsulated, and some windows are old wooden single pane double-hung, and some have been replaced with single-pane aluminum frame.
Heating this place has always been difficult.

I'm planning on pretty much stripping off the interior.  (Mix of plasterboard and plaster/lath)

As long as it's stripped bare, I figure it's time to insulate, rewire, and replace windows.

Big question is "Where ROUGHLY, are you at in the world?" This helps determine your climate zone and some of the best practices based on said climate.
HVAC considerations in Corpus Christi, TX are MUCH different than they are up in Nome, Alaska.


Well. If the sheathing on the house is still good, you're in luck.
You'll want to do proper fire remediation of course. Remove what you can of anything fire or smoke damaged.
If not, use sealers (NOT JUST PAINT AND PRIMER) on anything smoke damaged that has to remain.

Now. Moving forward. Are you trying to do it cheap? Or do you have a bit of wiggle in the budget?

If the house was pretty much uninsulated, ANYTHING will be better.

But if you want to insulate WELL, consider moving to a double-stud wall for exterior walls. This will grant you the space necessary to put in sufficient insulation.
Do pricing on blown-in vs batt.
Also, while lots of people here don't care for spray foam, possibly think about using it JUST to air-seal the outside wall cavities and use a different insulation inside ("flash and batt" or "flash and fill")

Also, if you're doing blown-in, with a double-stud wall, you could seal the wall on the EXTERIOR side of the inner stud wall. This gives you a perfect chase area for wiring and saves you from insulation mess if you ever have to dink with the wiring again.

If you're looking at ripping the siding off the house, look at going with exterior insulation (foam or Rockwool panels). Properly sealed, this would mean you can insulate the interior without sprayfoam and still be well air-sealed.

In fact, take your time trying to find and seal air leaks. The more of these you can get rid of, the tighter your house will be and the less you'll spend keeping it heated/cooled.


Also, while everything's open, take the time to double-check for things like mold, roof leaks, etc and remediate.
If you see anything that's going to require a tear-off, recommend insulating with foam board on the outside to bump your R-Value and provide an air-tight layer.

Is the roof vented with soffit/ridge vents?
If the roof is vented that way, possibly look at putting baffles into the rafter bays to provide clear ventilation channels for the roof surface without losing insulation uniformity to ventilation wash.
Again, you can seal the baffles in with sprayfoam, or you can simply blow into the rafter bays UNDER the baffles.

If not, or if you want to add still more insulation (whether out touch the outer roof or not), and you have clearance inside, you can lay strapping across the insulated stud bays.
Then use foam board, or Rockwool PANEL insulation.
Then strap the wall "vertically" again and you have someplace to hang your sheetrock.





ALSO, while everything's open and you're WIRING:

1: If your current breaker box is anywhere near full, or you're still on FUSES, upgrade to a slightly larger breaker box.
2: Pull your own coax cable to EVERY ROOM (save maybe the bathrooms and closets). And place it right where you plan to put the TV.
3: Pull yourself a couple runs of CAT-6 ethernet cable to every bedroom, den, the frontroom, kitchen, anywhere you'll have a TV, etc. Wifi is "okay" but wired internet direct to your cable gateway RULES!
4: With every different type of cable (save electrical) pulled, make sure to also pull a piece of waxed string too. This way, if you have to replace a cable run, you can tape a new cable to a piece of waxed string, tie the new string to the old, and fish everything through.
5: Take the time to map out, and label EVERYTHING. In addition to any "utility" boards you hang on the wall (like the backer for your breaker box), suggest building a network routing box for your coax/ethernet network.

Example shown in this image: https://s9.postimg.cc/oug303ha7/2018-05-14_20.10.49.jpg

Also, if you're smart, you'll actually build it as a BOX. This way you can put a common sized air-filter over the top/front to cut down on dust accumulation.

There's a lot of glazing on this house.

If you're essentially replacing it all, look at double-pane.
Also, look at varying the glass coatings in the windows on your east and west facing with an eye towards low solar gain there.

Other areas.
The bump-out on the right-hand side (and anywhere else you have a interior area over-hanging exterior space in this manner).
Pop the bottom off the exterior and see if it's insulated and air sealed. If not, do what you can there.
If the floor in that area's damaged and you're replacing said floor anyhow, you can do it from the inside instead.

Since your house is a gut, it's likely that you're replacing the HVAC system too.
Clue your HVAC consultant in so they can run a proper Manual-J to "right-size" your new HVAC setup

Also, if you're gutting. DEFINITELY talk to an architect about all the interior re-framing you're going to be doing.
If you strip this sucker out, you may as well put it back together in a way that gives YOU optimal use of the space.

Also, if you have any plumbing up against exterior walls, take the time to relocate them a bit.
Basically try to reduce the chances of you accidentally freezing a pipe to essentially nothing.

Hot and cold water lines.
Pipe insulation (the little "pool noodle" things) is your friend.

Keep all plumbing and wiring runs as uncomplicated as possible.

I'm on Whidbey Island, WA. A bit north of Seattle.
Since the siding is undamaged, and the house was painted last year, I don't plan on doing anything to the outside. (Well, other than replace windows)
I do have to do this on a fairly tight budget, as it was not insured when the fire occurred. (Had almost got it up to code so that I could insure it. sigh.)
I'll be doing some of the work myself (wiring/plumbing for sure), and have some good helpers to do the regular construction.

There will be a (hopefully small) amount of damaged wood that will need to stay. Suggestions on Sealer to use?

All the walls are going to be stripped down to the studs to get rid of the smoke/water damaged plaster.
I hope to remove a couple of the inside walls (living/dining/kitchen) to open up the main floor. I may need to leave a post (or put in a big beam) where one of the walls was.
Will Remove the old wood burning stove/fireplace, and the old oil-burning furnace. Will definitely remove one of the chimneys (steel pipe), the other is brick/rock right up through the middle of the house. Thinking about removing that one as well.
ALL the wiring is being replaced. (I don't THINK any of the old knob and tube stuff in the attic is still connected...) It had an old 60A service panel that had been abused multiple times.
Likely replace all the windows, due to single pane and many aluminum frames.

The house has NEVER had a good furnace, and the 2 side bedrooms have always been cold/hot unless you left the door wide open all the time. (ditto the big upstairs room.)
I'm planing on using mini-split heatpumps as the heat (and air conditioning).
Some of the walls should be stripped tomorrow, so I can verify how it's built.
I do expect to need to do something to make the walls thicker, so they can be insulated decently.
It would be great if I could just use fiberglass batting, though I may need to add some vents to prevent dampness.
I don't think there are any roof vents at all. The upstairs room was probably the original Attic, so I need to figure out how to insulate the roof.
There are a couple of skylights up there that I will need to replace soon, as their gaskets melted.

Okay, the exterior walls (and roof) are 2x4 (a full 2" x 4"). Siding is nailed on over planking.
There are NO vents anywhere. Not in the roof, gables, walls, eves.

Sealers: Killz makes odor and stain blocking sealers. Fiberlock makes Recon Ultra.

Do a bit of pricing on batt insulation and talk to a couple insulation contractors on blown-in insulation and get a price comparison.
If your 60A panel's that beat up, upgrade it. Breaker boxes aren't terribly expensive. $60-150, depending on how elaborate you wanna be.

If you're going to go with a mini-split, look at 3 air handlers. One for each bedroom, and one in your main living space.

As noted, you can go with a strapped wall system (which you'll likely want to do on the roof). But it probably makes more sense to just go double-stud.

Again, unless you're going to tear the roof off, go with batt insulation, strap horizontally, then go with board insulation (foam or Rockwool), then strap vertically again for either another layer of insulation or for your sheetrock.

If you're adding vents, use rafter baffles. Make SURE you detail the end of the rafter bay, down into the soffit like is shown in the images in the link below.
https://www.homedepot.com/p/Owens-Corning-Raft-R-Mate-22-1-2-in-x-4-ft-Attic-Insulation-Rafter-Baffle-Proper-Vents-70-Pieces-70RM/204853491

Since you've got 2x4 rafter, the baffles will essentially take up most of the space. So, if you're not going to go spray foam to fill the remainder of the cavity, go with a double layer of foam board on the interior of the roof.

And cutting soffit vents is fairly straightforward. You simply cut into the soffit and put a vent grill over it.

You'll either need a vent fan or a ridge vent to make the system work right. This will involve peeling back the last layer or two of shingles near the ridge.

Wiring - Will definitely be upgrading to a normal 200A service entrance and panel. Will be ripping out ALL the old wiring.

For the mini-split, it's interesting that buying 3 small independent units is cheaper than buying a single larger 3 head unit.
(as I said before, I am doing this on a tight budget)

So, for the walls, you seem to suggest that I can do either fiberglass batt, or blown-in (which I assume would be done after installing the plasterboard.) Do I need to worry about ventilation for the wall areas? (I haven't checked to see if they open into the crawlspace yet.)

Isn't some kind of rafter venting a requirement to prevent dampness causing wood rot? (Interesting that Owings Corning doesn't want to admit how thick the rafter baffles are.)
If I don't fill in the 4" space after rafter vents, and just apply foam board over the rafters - what would be the point of the rafter vents, since the rafters are essentially open?

Since there is already going to be some roof work to patch where the 1 (or 2) chimneys are removed, I'd probably add a ridge vent.

1: You can actually do the blown-in with a netting BEFORE applying sheetrock. You can do fiberglass or Rockwool in batts. You have several options for blown-in. Fiberglass is one of them, cellulose, etc.

2: If your home sheathing is planks instead of sheet goods like OSB or plywood, your wall system is open enough to dry properly without additional venting.

3: The reason you want to leave venting space isn't necessarily for interior heating/cooling. It's to help keep the roof surface cooler. Otherwise you're decreasing the lifespan of your roofing (shingles).

Basic idea is cool(er) air comes in through the soffit vents. You leave just enough space with the baffles for air flow. And as the roof heats the air, it evacs out the ridge vent via convection. So, hot air rises and sucks cooler air in to get warmed up.

It also stops your insulation from becoming a dust filter and keeps condensation from the vent out of your insulation.

You can also look up DCI's SmartBaffle system.
https://dciproducts.com/smartbaffle/

I actually like it better because it staples to the truss/rafter, rather than the roof deck.

Also, how old is the current roof. I thought I'd seen it somewhere but can't seem to find it now.
If you're going to tear off the chimneys, it may almost make more sense to simply put a new roof on.

Wood siding over planks. Note that the siding has been painted MANY times, and looks to be sealed quite well at this point. Not a hint of light or draft through the cracks. Which is why I worry about needing to add vents. (I do need to check to see if they open to the crawlspace. Pretty sure they do open to the rafter area.)

Roof is only about 3-4 years old, so replacing it seems excessive. Both chimneys are fairly small - not big brick squares. One is a 10" metal pipe, the other appears to just be a ceramic tube. (I'm guessing the brickwork fell off years ago, I haven't been up there to check.)

I do lean towards things I (or a couple of helpers) can do myself, as I am on a tight budget.

So, make sure rafter area is vented between the insulation and roof. Not sure if I'll do foam boards on top of the rafters, or build out the rafters the same as I do the studs downstairs and do fiberglass batts.

If your stud bays have no top plate, you'll NEED to install fire blocking.

For the fireplace that's ceramic. Just break it up and drop the pieces down the flue.
And there's not really a good way to double-stud a rafters.
You can shim it. But only so much.
You can sister wider beams on, But that cuts down on both interior space and straightforwardness of the insulation install.

Price out 2x6 or 2x8 sisters for EVERY RAFTER, plus appropriate insulation.

Then price out 1x3 strapping and 2 layers of foam board (and check for reclaimed foam in your area).

One thing I was considering, since the existing studs/rafters are 4", was to add a 2x2 on to them - thus making them into 2x6 framing.

If you rip 2x4s into 2x2 (1.5" x 1.5") and attach them horizontally to the vertical 4" studs, you would effectively have a Mooney Wall (search google for more info) which significantly reduces the thermal bridging through the studs. Insulate with dense packed or damp sprayed cellulose for a very effective insulation system.

Mooney Wall with dense packed cellulose behind netting: https://www.builditsolar.com/Projec...eyWall.htm

Oooh, that does look interesting.
Wonder if I could do that with the roof 2x4 joists? (all of which are at a 12/12 pitch)

2x4 ceiling joists (horizontal) or 2x4 rafters (pitched)?

Assuming you meant 2x4 rafters, yes, you could install perpendicular 2x2s, but it would probably be better to install 2x4 on edge to get more insulation up there. Ideally, you need to maintain an air gap under the roof decking, so dense pack and damp spray cellulose isn't normally used in this application. You could possible install Rockwool Comfort batts which are 3.5" deep and rated R15 between the rafters. Assuming your 2x4 are full 4" thick, this would give you a 0.5" air gap above the insulation. Then install commercially available 2x4s (1.5" x 3.5") perpendicular to the 4" rafters on edge by toe-nailing or using 3" screws at an angle into the 4" rafters. Then install another layer of standard 3.5" deep fiberglass batts (R13) or Rockwool Comfort batts (R15).

Yes, Rafters. for the airspace, I was thinking i might be able to use the Owens-Corning-Raft-R-Mate you mentioned earlier, and then do the hi-density blown in over those.
Yeah, for the Rafters, using 2x4's to get more insulation space would probably be a good idea.

Started peeling more of the inside walls. Studs are at semi-random spacing, 10" to 16". Definitely do a Mooney wall to insulate.

Posted By CasaDelGato on 17 Sep 2019 01:02 AM
Started peeling more of the inside walls. Studs are at semi-random spacing, 10" to 16". Definitely do a Mooney wall to insulate.

LOL!  They don't build 'em like THAT no more!
(Thank God!)

Finally getting back to this project (busted trucks, winter, and Covid-19 delays)

One thing that may not have been clear is that the roof on this house is a Pyramid. There are no roof vents at all. (The external view shows a normal ridge - but that is a add-on to the back face of the original pyramid. (The house had been re-muddled several times in the past) I wasn't planning on insulating that roof, as the area under it is pretty much useless.
While I am planning on building out the rafters and insulating, is leaving some space against the roof enough? I'm worried about the complete lack of venting.
It would be really hard to add vents, as most of the gaps between rafters end at one of the edges of the pyramid.