House insulation - interim report

[lml999]

We're adding insulation through a state run program in Massachusetts, providing a 75% reduction in costs up to $4000 annually. Not sure who is behind it, the state or the power companies...

Anyway, due to a variety of issues, what should have been a one day visit has turned into a two day + job.

On day one, the team did all the top sealing in the attic, put an insulated box above the attic pull down steps, and applied some 2" rigid board to about 200 sq feet of exposed wall in two attic areas. These walls are 2x4, insulated with fiberglass batting, and have some exposed outer surfaces in an unheated area. They also changed two bathroom vent hoses for insulated hoses.

They could not blow cellulse in before the HRV is installed. I thought they were going to install the HRV...turns out they won't... Oh well.

So I'm having a heating guy run the ducting for the HRV, then the insulation company will come back and blow 6" of cellulose throughout the attic and run R30 fiberglass batting on the exposed portion of the cathedral ceilings. They will also blow some insulation into an exterior garage wall that sounds suspiciously hollow.

I was interested to find that the upstairs hallway seemed a lot less drafty after just the topsealing. Some of this is probably due to the previously very poorly sealed attic pull down steps. I'm looking forward to seeing the impact of the cellulose on top of the work already done!

 

[Wickets]

I am soooooooooo jealous. Remodelling my house 18 months ago, we called several insulation companies for quotes to get the attic sealed ...1600 /sqft started around $5k. At least you live in a forward thinking state. Good luck with the finished job

 

[peakbagger]

Those state energy programs are great (NH has a similar one) and I encourage those who can to take advantage of them. Just realize that's its not free, these programs usually get funded by an conservation surcharge on power bills. As I tell folks, might as was well take advantage of these programs as otherwise you are paying for your neighbor to take advantage of it.

I took advantage of the NH program several years ago. Overall it did well but I did have several areas where the foam shrunk on an attic ceiling and wall section and I ended up with big gaps. The installer sprayed some other type of foam in to full the gaps while under warranty but several years later there are several other areas that need rework including a few spots where the foam is entirely loose from the cavity.

 

[Babaganoosh]

I don't think I have any of those programs here in NJ. One of the top 3 heavily taxes states and nothing. Figures.

 

[woodgeek]

Save your utility bills, and tell us therms per degree day before and after!

 

[lml999]

Save your utility bills, and tell us therms per degree day before and after!

We've only been in the house since June, so I don't have year to year comparisons. I'll see if I have enough information to be able to do week to week, month to month comparison...

 

[lml999]

Another interim report:

We're in the middle of an HRV installation, may be completed later today. Then the insulation guys will come back and blow cellulose into the attic. They will also run R30 fiberglass batts on the sides of our two cathedral ceilings (one side is accessible from the attic).

Our house is 22 years old and yesterday I replaced the door seals on the front door and the door leading to the garage. The seals appeared to be original, and the ones on the front door were pretty chewed up. I used M-D Premium weatherstripping. I was surprised at how easy it was, and how much difference it makes in the amount of air getting past the door (or not).

I've got two more doors to do, a glass door opening out onto the deck, and a set of French doors in the basement (walkout). Yea, it's a nice house.

I also have to replace a couple of door sweeps...it does feel like I'm making progress!

 

[DickRussell]

.....They will also run R30 fiberglass batts on the sides of our two cathedral ceilings (one side is accessible from the attic).

Assuming you mean a vertical framed wall between attic and the top of the room with cathedral ceiling, make sure they cover the batts with some vapor-open but air-tight sheet material, such as housewrap. That will keep thermal air currents from sweeping warm air next to the sheetrock up and into the attic space, replaced by cold air flowing into the batt from the attic floor area. How will they access the other side?

 

[lml999]

Assuming you mean a vertical framed wall between attic and the top of the room with cathedral ceiling, make sure they cover the batts with some vapor-open but air-tight sheet material, such as housewrap. That will keep thermal air currents from sweeping warm air next to the sheetrock up and into the attic space, replaced by cold air flowing into the batt from the attic floor area. How will they access the other side?

Sorry, the configuration is a bit different. The vertical framed wall has standard faced insulation installed in between the studs. The insulation company then installed rigid insulation over that, making a pretty tight wall.

The area in question is the sloping section of the cathedral ceiling. On one side, it conforms to the roofline, and there's fiberglass batting already installed. Nothing further to do there.

On the other side, the sloping ceiling is exposed to the unheated attic, and I can add more insulation to that. There's already fiberglass insulation in between the ceiling rafters. We're going to lay additional batting perpendicular to the rafters.

 

[DickRussell]

....The area in question is the sloping section of the cathedral ceiling. .....On the other side, the sloping ceiling is exposed to the unheated attic, and I can add more insulation to that. There's already fiberglass insulation in between the ceiling rafters. We're going to lay additional batting perpendicular to the rafters.

So, there is a roof above the framed cathedral ceiling there? Anyway, the steeper the ceiling plane, the more likely you'll get thermal air currents flowing through the batts. It still would be good insurance to cover the top of the added batts with something like housewrap, air-sealed tightly top and bottom, to prevent those currents, winter and summer. It's cheap and easy to do, assuming access to the space is adequate, which I presume is the case so that the new batts can be added. Heck, you can do that part yourself.

 

[lml999]

HRV installation was completed and I'm seeing a 5-8 degree difference in exhaust and fresh air inlet temperatures, on a 15 degree day. I consider that quite acceptable.

 

[velvetfoot]

The 22 year old house needs an HRV?

Save your utility bills, and tell us therms per degree day before and after!

But, he burns wood!

 

[lml999]

The 22 year old house needs an HRV?

But, he burns wood!

To the first, the house was built well and was pretty tight when we bought it last year. We've tightened it up some more, so yes, according to Mass Save, who did a blower door analysis, we needed to do something about air turnover. Their first recommendation was to install a bathroom fan that runs continuously at low speed. That didn't work for me...it would be exhausting heated air and potentially messing with the draft on the stove and boiler.

To the second, unfortunately my insert has not yet been installed. It's waiting patiently in the garage. We've got other expenses ahead of that...

 

[lml999]

Had something unusual happen earlier this week. We had 14" of snow and then a warm up. The roof (underside) on the north side must have developed a lot of frost, because when the temps rose, it started raining in the attic.

This was after the top sealing was done but before the cellulose was blown in. Some of the fiberglass batting was disturbed...but I'm not sure where all the moisture came from. The insulation company installed the vent chutes in each joist bay so the insulation should not be blocking the venting.

What I think happened was that the snow covered both the ridge vent and the drip edge vent. Yes...we have continuous drip edge venting, and no soffit venting. Inspector commented that this was a good system. Well, maybe so, unless snow covers the vents. I may have to put in soffit vents to supplement the drip edge vents...although that won't solve the problem of the ridge vents being blocked with snow.

That was earlier in the week...yesterday the insulation company came back and blew in 6" of cellulose on top of the existing fiberglass batting. I would have liked more, but that's what Mass Save was underwriting... They also laid R30 fiberglass batting on top of the existing insulation on the cathedral ceilings.

And...while they were here, I had them blow cellulose into the garage wall and over the garage. The garage is semi-attached, and I guess the builder figured that the garage didn't need to be insulated. I'm curious to see how much warmer the garage will stay with this added insulation. The slab stays pretty warm and two of the garage walls abut heated space. A full size refrigerator may also generate some heat.

It's pretty warm here today, so I can't tell the difference the additional insulation has made. We'll see...I'll be keeping track over the next few months, will see if I can compare before/after temps and NG used.

So...I still have to sort out the ventilation issue. I'm also thinking about augmenting the R value of the attic hatch cover. I think it's at R6 currently...might add another layer of rigid insulation. Would like to get it to at least R30...

 

[woodgeek]

Roofers say that if the soffits are open, the ridge vent clears itself from the warm airflow. Also remember that (fluffy) snow is air permeable.

I left my old gable vents in place after getting soffit and ridge vents added, even though you are 'supposed' to close them off. No problems so far.

 

[peakbagger]

Blocked ridge vents is an issue in my area, if the ridge vents don't work, the soffits don't work and you are risking ice damming. I do not believe the contention that ridge vents will clear on their own fast enough to avoid the inevitable ice damming that can occur after a big snowfall. I have vents on my garage that I can see out of my window and one good snowstorm will block them for weeks. I have standard gable end vents on my house in addition to roof vents. Some folks argue that that somehow short circuits the system but every indication on my place as it works better to avoid ice damming as I always have air flow through the soffits even with snow on the roof. Heat rises and I really don't care if it exits the attic at the ridgepole through the ridge vents or through the gable end vents as long as ii is supplied up through the soffit vents. There was a local builder in my area that would built elevated vertical vents that looked like louvered purple martin houses stuck on top of the ridgepole. They didn't look very attractive but they were tied to a big hole in the decking on either side of the ridgepole and were high enough that that least some of it was sticking above the snow. Those building also have extensive soffits vents and rarely have I ever seen an ice damming. By the way, most builders put in way too few soffits. Ideally you want a continuous vent slot the length of the roof. Those ones that fit in core drill holes work but you need far more than most folks put up. I would advocate a 3" vent for each rafter bay if you decide to use them.

Attic hatch covers are a big culprit at introducing moisture into an attic and without working ventilation I have no doubt that warm humid aid came up through the hatch and other smaller openings and then condensed on the cold roof. Years ago I bought an old house that someone had tried insulating, they stuffed insulation down in the soffits and blocked the rafter space for air to go up between the top of the wall and the roof. There was only one vent at the top of the roof and it was stuffed with insulation. The house had a new roof with very wide flashing. There was water damage repair on the inside walls. I expect they had ice damming and decided the way to fix it was a new roof and then decided to sell it quick. I spent a bunch of nights after work with a headlamp on with a pole with hook on it pulling out the insulation from the soffits and then put in "proper vents" and put in new insulation. I only owned it one winter but never saw a bit of ice damming. I have seen several very expensive homes built where they didn't get the venting right and the beams in the attic were black with mold a few months after the owner moved in. Get the ventilation working and the problem goes away. Folks don't realize how small a gap it takes for vapor to try to equalize from one side of a barrier to another. Unless you come up with attic hatch that has a resilient gasket that can be compressed its going to leak. Just try the dollar bill test on most hatches and they will fail.

Of course the other culprit is bathroom and kitchen exhaust fans where the duct work is not connected or leaky so it dumps into the attic.

One other trick is if you do put in gable end vents, make a tray out of plastic and put it inside the attic in front of the gable end vent. IWind driven powdery snow can make it in past the screening and land on the insulation where it will eventually melt and wet the ceiling down below. I see many older homes with brown stains in the ceiling where this has happened.

 

[lml999]

Attic hatch covers are a big culprit at introducing moisture into an attic and without working ventilation I have no doubt that warm humid aid came up through the hatch and other smaller openings and then condensed on the cold roof.

Thanks...the hatch cover was a kit made up of rigid insulation assembled onsite. There's a compressible gasket on the bottom, all the way around, and it mates nicely with flat flooring. I just took a peek upstairs to see how we're fairing. Things look okay after a cold night and warmer (42) day. I put a remote thermostat up there to see how the temps track as a (bad proxy) for moisture incursion.

I probably do need to cut in a gable vent.

 

[nEWRfire]

I don't think I have any of those programs here in NJ. One of the top 3 heavily taxes states and nothing. Figures.

you can get up to $4k rebate and a 10k 0% loan in NJ

http://www.njcleanenergy.com/reside...ce-energy-star/home-performance-energy-star-r