All these house renovation threads got me motivated

[Blaze]

When we bought our house two years ago, the upstairs was unfinished. We had grand plans of finishing it off, but the business grew and I got really busy with it and it fell off. I had already finished the electrical and a lot of the framing, but stopped there. We decided to get some quotes on having someone finish it for us. It is a basic 550sqft open area with a storage closet on one end. There are a lot of nooks and things, but overall not bad. Framing is almost done, no plumbing, electrical is installed and inspected, HVAC is in, etc. Basically finishing framing, sheetrock, finish work, etc. Quotes ranged from $11k to $30k.

F a buncha that.

We talked about it and decided to take a couple nights a week and just start knocking it out. I took the quotes and started going down the list knocking stuff out. One of the things that needed to be done was to fir out the roof joists for the R-30C insulation since they are 2x8 and I need an extra 2" (insert joke here). Lowest quote to fir out the space was around $3400. I went to the store, bought about 400ft of 2x2 firring strips, spent Saturday gluing and nailing them to the joists and other areas that needed them. Spent about $150 in materials and finished it up. Tonight I am going to finish the framing, have one area that I need to add a couple boards, and then install the air barrier at the knee walls and then I'm calling for the framing inspection. Then I start sheetrocking.

Plan is to hang sheetrock and then pay someone to mud the space. I'm not about to do that crap by myself. Then I'll do the finish carpentry and paint, then have someone lay the carpet.

Here is the main space after I finished the framing and roughed in electrical. It pretty much looks the same now except 2" firring strips on the joists and a lot more construction trash.

 

[shawn]

If I had to make one comment, it would be to furr down more than 2". You need to account for air movement on the underside of the sheathing. I'd shoot for a minimum of 4" of clear space.

Good on ya for buying unfaced insulation, though.

 

[6BangBronk]

If I had to make one comment, it would be to furr down more than 2". You need to account for air movement on the underside of the sheathing. I'd shoot for a minimum of 4" of clear space.

Good on ya for buying unfaced insulation, though.

Shawn, you've addressed unfaced before but I never asked. What's the benefits besides a lot cheaper and easier on the sheetrock install? I always thought a vapor barrier of some kind was needed anywhere warm air and cold air meet? So the only application I've ever used unfaced before was in a crawl space where the barrier was plastic on the ground.

Now on my rental, I used all unfaced on my addition but I tacked up sheets of plastic before the sheetrock went up. Was just cause I had a line-up on cheap unfaced. But I did experience it was tremendously quicker than messing with the crappy paper faced, but I thought it was necessary?

Also noticed other people doing unfaced as well with no barrier. I know I had a couple mold issues around the old windows facing north in my farm house before I totally redid / insulated the walls. I went with faced.

 

[6BangBronk]

Oh, and they have these dittys you install on the under side of the roof that push the insulation down for ventilation when there's no attic. Don't know the name but the ones I saw was thick cardboard. I'd imagine you could use / make anything to accomplish that.

 

[RatLabGuy]

Oh, and they have these dittys you install on the under side of the roof that push the insulation down for ventilation when there's no attic. Don't know the name but the ones I saw was thick cardboard. I'd imagine you could use / make anything to accomplish that.

you mean like thise vents?
ADO Products Durovent 23-1/2 in. x 46 in. Attic Ventilation System with Built-In Baffle 10/Ctn-UDVB234610 - The Home Depot

I'm a little confused as to why we're (well Shawn) is talking about venting, b/c that's only the case if you have soffit vents allowing air to flow up into the space? In this case wouldn't it be a sealed scenario where you have no soffit vents and no air flow? as so-called "hot roof"?

On that note, I'm curious as to why go through all the trouble and expense of firring out the rafters to make room for fiber insulation, instead of doing spray foam which would have a much higher R per inch. Yes, it's expensive, but all that firring + glue + bracketry, screws etc - not to mention PITA of hauling all teh wood up there - isn't cheap either.

 

[6BangBronk]

you mean like thise vents?
ADO Products Durovent 23-1/2 in. x 46 in. Attic Ventilation System with Built-In Baffle 10/Ctn-UDVB234610 - The Home Depot

Yes exactly. "Baffle" I guess it's called.

The ones I saw were much older version. Simple device to come up with something yourself though if needed.

 

[6BangBronk]

If I'm seeing right, there's tar / felt paper on the exterior between siding and studs which would probably suffice as adequate moisture barrier there, but nothing between room and remaining attic here.

 

[RatLabGuy]

Yes exactly. "Baffle" I guess it's called.

The ones I saw were much older version. Simple device to come up with something yourself though if needed.

If you buy them in bulk they're pretty cheap. Also make w/ perforated areas so really easy to snap to length etc.

I've been adding insulation in the attic (on top of the existing layer), so I've been using these.
However in my house, at some point (or may be original?) they plywooded over the soffits so there is no ventilation. Several years ago they even put in new AL siding on the soffits, and put in perforated panels - so it looks like they are ventilated - but the !@#$ guy that did it didn't actually cut holes through before putting teh siding on. I've learned that doing it now will be a real PITA b/c all the gutters etc will have to come off, plus the siding, to do it. So it remains unvented. Doh

 

[Blaze]

The reason I did 2" rather than 4" is because the walkways are pretty narrow and dropping to 4" would make it really awkward and cut into the room a lot.

I'm using a mix of faced and unfaced insulation. The previous owner left a ton of it here so I'm just using what I have before I purchase anything. The insulation you see there is what was put on with the house.

 

[Blaze]

On that note, I'm curious as to why go through all the trouble and expense of firring out the rafters to make room for fiber insulation, instead of doing spray foam which would have a much higher R per inch. Yes, it's expensive, but all that firring + glue + bracketry, screws etc - not to mention PITA of hauling all teh wood up there - isn't cheap either.

Had an inspector come out to give me a consultation to tell me what all I need to do to pass when I call them. He told me I had to fir our the joists, so fir I did.

Plus I only have under $200 in the firring, and my wife and kids carried the wood up for me.

 

[shawn]

I always thought a vapor barrier of some kind was needed anywhere warm air and cold air meet?

I tacked up sheets of plastic before the sheetrock went up

That's a good way to end up with a moisture problem. Whether or not you have a vapor barrier (and where it's located) is heavily dependent on where you are in the world and the type of weather that you experience. Around here, you want to make sure that any water vapor that is in the house is able to migrate out as easily as possible. We have a mixed humid climate, so water vapor moves in both directions through the wall. If you have a polyethylene sheet on the interior face of the studs, warm moist air moves through the wall from the exterior during the summer, reaches dew point near the interior face of the insulation, and condenses on the polyethylene, wetting the insulation, the studs, and creating the potential for mold growth and rot.

I'm a little confused as to why we're (well Shawn) is talking about venting, b/c that's only the case if you have soffit vents allowing air to flow up into the space? In this case wouldn't it be a sealed scenario where you have no soffit vents and no air flow? as so-called "hot roof"?

Due to wetting of the underside of the sheathing. The dew point in that roof assembly during cooler periods (think winter or spring/fall at night) is going to end up somewhere just below the roof sheathing, probably in the upper inch or so of the batt insulation. Fiberglass insulation doesn't like getting wet, and neither does roof sheathing, so you try to provide plenty of room on the underside of the sheathing for air circulation. Ideally, you would have a ridge vent and a soffit vent to encourage stack effect in those joist bays, but having some air space there is better than not.

Those baffles are fine, but I would limit their use to down in the bottom corners where the ceiling insulation tends to block up the joist cavities. They're not tall enough to allow for sufficient air movement over a long span (which is why I lean toward 4" of clear air space if you can get it).

Most of the moisture is going to migrate up and out through the roof, so you want to pay closest attention to it there.

pray foam which would have a much higher R per inch

Because it's massively expensive, among other reasons.

I'm using a mix of faced and unfaced insulation.

PEEL OFF THE FACING AND THROW IT AWAY.

Also, make sure the mechanical ducts are running within the insulated envelope of the house as much as is possible. They tend to not work very well if they have to run through unconditioned attic space first. Ditto for the location of the air handler. It should not be in unconditioned space, especially not in an attic.