Poor Insulation.

[AeroEngy]

I have a house that is about 7 years old which I have owned for about 3 years. I have come to find lots of things that were not built correctly.

The upstairs is a finished attic space with 2 bedrooms and a bathroom. It is one where there is a knee wall and part of the ceiling is sloped. It is always hot in the summer and cold in the winter. This winter it was especially bad because of the wind. So I finally decide to cut a hole in knee wall and see what was going on in there. Below are pictures to what I found. Basically behind the knee wall is open to the outside, there is no insulation behind the drywall, and the air gap that is suppose to vent the joists spaces is incorrect. Here are some pics.

The bump out is for the dormer windows. There are three open uninsulated joists spaces that lead over the front porch. Also they insulated the bump out for the dormers but not the 25 feet of knee wall. WTF

Looking through the open joists over the porch

No Insulation on knee wall and note the air gap at the roof is between the paper vapor barrier and the drywall and not between the insulation and the roof line.

Also there is no insulation under the subfloor.

My plan is to at least insulated the knee wall with R-13 batting, wrap the outlets, and foam any gaps I see. Plus shut up most of the open joist spaces. Leaving a little open for venting. The open joist make it a tornado of air behind the knee wall.

I might also blow in some insulation into the floor joists. Note: There is finished living space below this subfloor. Any other suggestions.

EDIT: Add overview slide for clarification ... hopefully

 

[drnickriviera]

Hard to tell dimensions from the pictures, but it doesn't look that big. If it were me, i'd block off that area to the porch, install the styrofoam rafter vents, you could remove some of the subfloor as well, then fill the thing top to bottom with blown in cellulose

 

[AeroEngy]

It runs the length of the front of the house about 30 feet. There are dormers on each end. There are open joists in front of each dormer. The uninsulated knee wall is about 5 feet tall. The shorter part at the end of the box out for the dormer is about2.5 feet. Just enough to crawl past to get to the other side. Also the joists under that subfloor run pretty much the width of the house.

 

[Jumpem]

I wouldn't do fiberglass bats as they leave air gaps everywhere. Do spray foam under the roof and along the walls. Blown-in loose insulation 18-24" deep over the floor.

 

[TraumaRN]

Looks kinda like my attic but in reverse...For me none of the rafters are insulated whatsoever, the subfloor and kneewall have R-30 and R-19 respectively, but nothing on the rafters, and like you I have a ginormous tornado of air coming from my porch which I'm going to mostly seal as IMO there is a difference between air flow and massive tornado of air. Good luck with yours...I've got $1000 worth of insulation in my garage waiting to be used on Wednesday

 

[waffleironhead]

Since when was insulating the rafter a good idea? Isnt there still a concern for trapping moisture between the insulation the the underlayment causing roof failure? I know you can place those egg carton foam spacers under the insulation to form a vent system. Have things changed since I got my (unused)degree in Arch, tech?

 

[Dubb]

pictures and info aren't really complete enough to figure out what the best course of action would be, though something obviously needs to be done.

but I'll say this - it is exceptionally common for DIYers to screw up insulation systems, usually in an effort to better insulate, they wind up creating moisture and condensation problems - which some of the things suggested here would do.

There are enough "green" energy efficiency type firms around now that it's probably worth calling one of them.

 

[feralkid]

Since when was insulating the rafter a good idea? Isnt there still a concern for trapping moisture between the insulation the the underlayment causing roof failure? I know you can place those egg carton foam spacers under the insulation to form a vent system. Have things changed since I got my (unused)degree in Arch, tech?

You are correct, sir.

The area in the photos looks to be an unheated "attic" area, therefore the knee wall and the floor should be insulated, but NOT the rafters.

 

[Dubb]

Since when was insulating the rafter a good idea? Isnt there still a concern for trapping moisture between the insulation the the underlayment causing roof failure? I know you can place those egg carton foam spacers under the insulation to form a vent system. Have things changed since I got my (unused)degree in Arch, tech?

depending on when you got your degree, maybe. Vented roof systems are no longer the presumed standard in new construction, most codes now say you can do either sealed or vented as long as you meet the performance criteria. Done properly, sealed is better, but it is harder to do properly - these days it mostly involves closed cell spray foam.

I would always be hesitant that a vented could be easily converted to sealed without issue. that's basically asking for trouble

 

[feralkid]

Looks kinda like my attic but in reverse...For me none of the rafters are insulated whatsoever, the subfloor and kneewall have R-30 and R-19 respectively, but nothing on the rafters, and like you I have a ginormous tornado of air coming from my porch which I'm going to mostly seal as IMO there is a difference between air flow and massive tornado of air. Good luck with yours...I've got $1000 worth of insulation in my garage waiting to be used on Wednesday

Don't insulate the rafters. If you have too much air, cover some of the vents until you have the correct proportion of ventilation to attic footage. The amount may vary, depending on your local climate, but it will not be hard to find this information.

If you want to add more insulation to the walls and floors, go for it.

 

[TraumaRN]

The problem is my house is basically never shaded from sun. So both sides of my attic, get roasting hot in the daytime(and consequently everything else upstairs roasts). I looked into installing powered fan vents to help disperse the air but it'd involve lots of wiring/tearing holes in walls etc.

And yes part what I want to insulate is the walls which with R-19 in Michigan certainly isn't adequate at all. The rafters I've heard arguments both ways when I had estimates done, I'm going with insulating them because they actually make up part of the ceiling on both sides of the master bedroom, I figure if I at minimum insulate that part of the ceiling it can cut down on heat/cold loss.

 

[TraumaRN]

Oops double post...damn internet.

 

[Red Squirrel]

Wow yeah I'd add way more insulation. As mentioned just make sure you don't block the overhang vents. You can use those foam gables to help.

 

[AeroEngy]

I added a crudely drawn overview to help clarify.

Couple of notes:
1) I don't really have overhang vents since the whole thing is practically open to the front porch.
2) It is unheated attic space. However, the roof rafters have to be insulated ... at least over the the finished drywall. The vented air gap is on the wrong side. Allowing the hot/cold air to flow directly over the drywall on the sloped finished ceiling. Gap should be between the roofing plywood and the fiberglass.
3) I haven't looked in attic space 2 or 3 on the drawing. But I know I at least have a ridge vent on top of the roof.

Thanks for the feedback.

 

[drnickriviera]

Is it possible to get access to attic 3? It's not going to be fun, but if you want it done right the first time, i'd rip it all out and get the air gap on the right side, then reinsulate that section. I've made some rafter vents out of foam board with the foil backing. Cut some 1" sections and glue them on. You get the added benefit of a radiant barrier. You could then block off the bottoms and fill the cavity with cellulose. I think it would be a pita to get fiberglass pulled back up to the top.

Then insulate the knee wall, possibly furr it out and use some thicker insulation.
Then pull up the subfloor and insulate from the outside wall to the knee wall.

So you basically want the insulation to go down the rafters to the knee wall, then straight down the wall, then the floor to the outside wall. Your ridge vent will now work properly and pull air from the porch and out the top, should keep the attics cooler

 

[waffleironhead]

1) Have you peeled back the rafter insulation to see if there are foam baffles underneath?
If not it looks like they did screw up by installing the batts so deep in the rafters. iirc you can get away with no baffles in a 12" deep rafter by using 10" batts as the 2" left between the batt and underlayment is enough of a vent cavity. I'm hoping for your sake that there are baffles under there.
2) fill those knee walls in with batts, and depending on local code you could top them with rigid foam(if you can get sheets into there).
3) you could safely build up some retaining wall between the attic and the porch roof overhang, using some scrap wood tp fill between the rafters and the floor. This would allow you to fill in that area with blow in to depth without it spilling out into the overhang area. I personally wouldnt block the vents up.

 

[AeroEngy]

1) Have you peeled back the rafter insulation to see if there are foam baffles underneath?
If not it looks like they did screw up by installing the batts so deep in the rafters. iirc you can get away with no baffles in a 12" deep rafter by using 10" batts as the 2" left between the batt and underlayment is enough of a vent cavity. I'm hoping for your sake that there are baffles under there.

Yeah I did. There is nothing under them. They are just pushed up to the roof.

I went ahead and put batting on the knee wall today. Still scratching my head about the rafters and what to do about the sub-floor. The floor joists are perpendicular to the knee wall and run over all the other rooms. So, it will take a ton of blown in insulation. Unless I rip up the sub-floor to the knee wall install some sort of header and only insulate up to there.

Is it possible to get access to attic 3? It's not going to be fun, but if you want it done right the first time, i'd rip it all out and get the air gap on the right side, then reinsulate that section.

I haven't made it into attic 3 yet to see what is going on. There is no access so I will have to cut a hole in the ceiling and take a look.

The sloped part of the ceiling over the finished space is probably about 6 ish feet long. It would be a huge pain to try to rip it all out. I wonder if could get something flexible but strong like a fiberglass tent pole and try to reposition the batting that is there. Maybe even insert something so the air gap stays on the correct side.