Insulating attic floor

[joesxm3]

I just finished an hour and a half and removed the insulation from the 10 joist bays on one half of the addition. I found three bays with mouse feces and one that looked more like the bottom of my cat's litter box.

It is nearly impossible to get to the roof edge side because of the way that the rafters meet the 2x4's that are the top of the second floor wall. From what I can tell the rafter comes down alongside the floor joist and then is cut at an angle and sits on top of the 2x4. I should have paid more attention but I think that the extra 2 inches of the 2x6 rafter is on the inside of the 2x4 rather than hanging over the outside, but I will have to double check.

I now realize I did not pay enough attention, so some of this may contradict but there is a 2x4 that has the 2inch part down and the 4inch part vertical that goes around the outside part of the framing. It may be nailed to the ends of the floor joists.

The net result is that near the edge the bottom is either the 2x4 from the second floor wall or the sheetrock sitting on top of the 2x4 and the outside wall is the 2x4 that is on edge going around the outside like a lip on a tray.

There is an opening about half an inch where the two 2x4's come near each other.

BTW - the head lamp was a brilliant idea. It saved my butt multiple times just on this short initial excursion.

I bought a tube of clear caulk this morning and have a can of Great Stuff expanding foam regular type. Heeding the warnings about the foam straw clogging and the need to do all the foaming in one session I think I may remove the other half of the addition and then try to get near the roof edge and foam the half inch gap.

So far have not been able to get closer than two feet, so I am hoping that my arm might stretch or that the foam sprays out with a little force so I do not have to be in direct contact.

I am considering trying to make a support that will be 14 inches wide and have some four inch hangers that will latch over the floor joists. If I do that I can put it into the joist bay and put some weight on it so I can get a few more inches clearance.

Although I am very careful about the ceiling, it seems that if I am sitting on my plywood crawlers I can put my leg down onto the ceiling as long as I don't lose my balance and put serious weight on the leg.

I am treating this like a haz-mat operation. I suited up and duct taped my wrists and ankles to avoid particles getting in there. I had the respirator, goggles and knitted cap so the only real opening was at my neck. I wish I had a turtle neck shirt or a disposable scarf for that - I will hunt something down for next time.

I decontaminated in the upstairs bathroom, took a cold shower to get particles off and am washing my clothes. That will take about an hour then back to work.

The decontamination practice will come in handy if someone blows off a small nuke in NYC and we get fall out

With regard to the low gable ventilation, would you think that cutting in the vent and then attaching some sort of long duct would be a good idea? I could run the duct along the edge of the attic and cut openings in the top of the duct every few feet to let the air come out - or do you think it might be better just to run a solid duct to the middle of the attic so the air flow is more consistent?

The house was built in 1960 and the addition sometime after that. However aside from grounded outlets the construction techniques seem similar.

I currently leave the attic hatch open about a foot in the summer and open a couple windows on my second floor to try to increase the air flow. I only use a small window A/C in my office so leaking air from the house to attic in summer is not a problem.

Do you think I should make a premanent crawl zone in the addition after I lay the 6 inch batts?

I don't think that the attic has enough space to stand up even at the peak, so making a study will not work. At this point I am full steam on plan A - insulating the attic floor.

As usual thanks for the advice. I really appreciate it.

 

[samclem]

There is an opening about half an inch where the two 2x4's come near each other.

Is there any chance that this is some type of intake vent for the attic, or just an artifact of the dimensions of the wood? I'm having a little trouble "seeing" the way the framing is done. It sounds like far too little vent area at any rate.

So far have not been able to get closer than two feet, so I am hoping that my arm might stretch or that the foam sprays out with a little force so I do not have to be in direct contact.

Sorry, but the straw has to be within about an inch of where you want the foam placed. I've had good luck in taping a drinking straw to the end of the factory-supplied one (use a lot of tape, and bring some extra straws into the attic with you in case one gums up. Again-very sticky stuff, watch your eyes and keep it off your skin. Don't wear clothes that you like).

With regard to the low gable ventilation, would you think that cutting in the vent and then attaching some sort of long duct would be a good idea? I could run the duct along the edge of the attic and cut openings in the top of the duct every few feet to let the air come out - or do you think it might be better just to run a solid duct to the middle of the attic so the air flow is more consistent?

Your duct idea sounds fine. Running them along the roof edge would give better results than my idea of running it down the middle (esp in the summer, as you'd get nice flow underneath the entire roof deck and out of the ridge vents.). It doesn't need to be much of a duct, you could just put a small "wall" of styrofoam up between the top of your attic-floor insulation and the rof deck, leaving a 1" gap at the top for the air to come out. The bottom of the duct would be formed by your new insulation, the (slanted) side/tp formed by the roof deck, and the "wall" inside formed by the styrofoam. The intake vents on the gable walls will need to be fairly large. When you are done you want the vent area (high vents and low vents combined, each comprising 1/300th of the ceiling area) to equal 1/150th of the total area of your ceiling. That's total "net free vent area", so it will actually have to be bigger to take into account the resistance of any grills/screens. Assuming your ceiling has an area of 1000 sq ft, you'd need 480 square inches of net free vent area down low. Add about 20% for low-loss screening over the vents and you've got a requirement for 576 square inches of vent. You could have four intake vents at the edges of your roof running to ducts along the edge, and maybe add other intake vents in the middle of the gable (with a duct down the center) if you need more intake area.

Do you think I should make a premanent crawl zone in the addition after I lay the 6 inch batts?

I would. You'll be back up there.

 

[joesxm3]

The gap was not intentional. On one end there is no gap at all, on the other end close to an inch and a half. I think it was just cockeyed construction.

It may have been some intentional or unintentional air flow at one time, but when the guys put the siding on they nailed a board all around the very top of the wall just under the gutter and wrapped it with metal. This effectively blocked off anything that might have been there.

I managed to finish 7 bays on one half of the new side and to put crazy foam in three. I figured it better to let the foam hardend before pushing the batts.

I ended up squirting a ball of foam about the size of a grape where I could reach and pushing it with a stick to move it to the gap. I probably should have had the large gap foam. I was really careful about getting foam on my, but came down with some on my hat and I had a hole in one finger of my glove. The tip of my middle finger is now stained black with two small dots of foam stuck to it

I found a good use for the old insulation. At the very edge of the roof edge it will be impossible to put the 9 inch R30 rolls. What I am doing is taking pieces of the old insulation minus the vapor barrier and pushing it with a long stick to fill up that area. I plan to fill up with that until the under rafter space is 9 inches tall above the joists so I can easily roll the R30.

??= it is ok to put the old insulation directly in contact with the roof plywood around the edges right? Since there are not soffit vents I do not have to worry about blocking ventilation.

I am suiting up for another session and will be up there in a few minutes. My goal is to remove the other half of the new area, caulk and lay the batts. My stepfather is coming for another dump run tomorrow and I hope to get 12 rolls of R30 in the truck. My calculations indicate I need around 30 rolls for the whole attic.

BTW - You told the story of running out of staples earlier. I had a similar incident. After loading the caulking gun and crawling like a flattened moust to the edge of the roof side where I could just barely reach with the caulk gun I found out that in addition to cutting the spout you need to pierce the foil inside - back down to the cellar to find a nail

One hopeful note - it may be an optical illusion, but it seems like the rafter angle is steeper on the back side of the house. It that is true there will be more clearance for me to crawl under to reach the roof edge.

Another thing, with the 9 inch roll insulation on the floor the gable vents are that much closer to the floor and might be better intake vents because of that.

 

[travelover]

............. I probably should have had the large gap foam........... .

The foam hardens and expands due to reacting with moisture in the air. You can make it really expand by squirting the surface of interest with a water spray first. Preheating the can helps, too if it is less than 70 degrees or so. Submerge in warm water - no microwave......

 

[samclem]

Congrats on the progress to this point, it sounds like things are going well. The Great Stuff will expand quite a bit, and it can do so with enough pressure to bend wood. The solution is to either use "just enough" or buy the "Windows and Doors Great Stuff" which expands less and expands with less pressure. You'll be fine with the regular stuff if you just take it easy and don't try t fill the gap for the whoe depth of the wood--you're just trying to stop the airflow, not add insulation, after all.

Stay safe up there!

 

[joesxm3]

I might have put too much Great Stuff, but it seems to just have expanded out rather than bending any wood. The foam is really hard to control at long distances, but I seem to be getting the hang of it - you need to plan for the extra amount coming out after you stop so let up ahead of time.

I managed to seal most all of the cracks in the new side and used one whole tube of caulk and two cans of foam.

It is much more time consuming and difficult than I expected but things are at least working out well. Given the tight space I have to plan every motion like an astronaut would on a space walk - that takes time. I am also very sore from using may previously undiscovered muscle groups.

The headlamp saved my butt yet again. Last night I knocked over the worklight and the halogen bulb crapped out. I was able to find my way back out of the attic with the headlamp.

One thing no one mentioned was knee pads. I bought a robo-cop pair from HD and they are paying off in spades.

I took a couple of side trips. I noticed that my back porch was desperately in need of staining and since it was 60 degrees for two days in a row I ended up doing the entire outside 12 feet by 30 feet by 8 feet and then the next day I did the part of the floor closest to the elements six boards deep and 2 feet along each side. It was not my best painting, but I went very fast and got the job done relatively quickly. My new respirator was nice since the stain I use is pretty toxic. I wore it for the initial sanding and for the painting. I could not even smell the stain at all while wearing the respirator.

I also picked up all the leaves yet again on my 1 acre lot, went to the dump, brought back 24 rolls of R30 insulation from HD and sawed up about 150 small logs for my wood stove.

At this point I have managed to do all the prep work on the new side and install 16 out of 20 batts on the roof sides of the attic. Four bays have special details such as extra 2x4 nailed in to attach sheet rock to or very many wires so I saved them for later.

In the middle of the room I will need to put in at least 10 more batts to finish things off, but I left them open until I get near the gable wall to put the insulation into the little 2 inch wide bays near the wall.

I am very happy with the quality of the Owens Corning batts. The are nice an fluffy and fill the joist bays perfectly.

I can now see the point about how much easier it would be to just blow in the insulation and be done with it in one day. However, I think that the sealing of the cracks in preparation would have taken three or four days - unless I skipped it and just blew over the old insulation. Given the double vapor barrier I would probably have had to at least lift the top layer and remove the paper - so a lot of demolition work in either case.

On another note - the new stove arrived today. It is very nice looking and matches the new white hood that we installed a few weeks ago. I still have to strip wall paper and repaint, but that will not be until next spring.

Thanks again for all the advice on this project. Although it will be weeks before I finish I will be proud to have done it and will rest easy with my R49 insulation in the attic.

 

[travelover]

Joesxm, slow down, man. You are making me tired just reading this....

 

[samclem]

Dang! Sounds like things are going rapidly and well. I did forget to warn you about the need for knee pads. Another thing that started to hurt was the palms of my hands (from the concentrated loads on the heals of my hands while crawling over the joists). I suppose gloves with padding in the palms would have helped. It got pretty bad after a few days, and I started to wonder if i wasn't causing some nerve damage in there. The pain went away about a week after finished, but if I had it to do again I'd look to buy (or make) something to prevent this problem.

Other small points:
- I bought some florescent marking tape and hung a streamer down from the roof deck directly over the point where there was a junction box, ceiling fan box, light fixture, etc under the insulation. I labeled the tape with the identity of the item. It's a small thing, but has already saved me time when I needed to locate something under the insulation--the hanging tapes are easy to see from a long way off. I just used a staple gun to tack them up.
- I took pictures of the insulation "before" and "after". I also photographed a few places where I'd done the caulking, etc. Someday I might want to sell this house, and this will go in the sales book.
- At the entrance to the attic I put a small data card with the date and showing the brand and thickness of insulation I'd installed.
- Light fixtures: Obviously, no insulation should be in direct contact with can lights or other fixtures unless they are rated "IC" (for "Insulation Contact"). You have to ether replace them with IC fixtures or build a box around them to (drywall is best) to keep the insulation away (I think the distance is 3," but be sure to check).

Congrats, and keep us informed on the progress.

 

[joesxm3]

I think I do not have any "can lights". All the light fixtures hang down inside the room and all I see from the attic is a metal junction box or a wire going down into the sheet rock, so I think I am ok on that.

Nice idea about the pictures. I have been taking quite a few. Once I got the first roll of R30 spread out it looked so dramatic towering over the in joist R19 that I took a picture to enhance the contrast.

I have been plugging along and today managed to finish off the new section 10 joists by 22 feet. The old section has 24 joists by 22 feet, but part is walled off for the bathroom cathedral ceiling.

I have been able to re-use about half of the old insulation. I use it to fill in on the edges and have rolled up some and pushed it into the roof-edge parts that are less than 9 inches tall so I can just roll the R30 next to it once I have the 9 inches of clearance under the rafters.

Rolling the R30 is certainly much easier than removing the old and squeezing to caulk and push the batts. I have used up three tubes of caulk and three Great Stuff cans so far, so it would seem I have a lot to fill in.

My hard drive has been giving problems, so I have not been online as much as usual. If I drop off the face of the earth it probably means that my hard drive died and I am working to move to my new Dell.

If I had realized what I was getting into I might have thought twice or maybe just rolled the R30 over the old stuff. However, I am happy to be doing things right. The more I think about the blown in celulose, the more I think I would not be happy with that much loose stuff all piled up in the attic, so I probably made the right choice for me with the pink fiberglass - but I do feel bad about not being as green as I like to think I am.

As usual, thanks for all the help.

 

[samclem]

I saw a product advertised in this month's issue of Fine Homebuilding that would be useful to those with a situation like yours. It provides intake ventilation for homes without soffits. Basically, when the home is re-roofed, a slit is cut into the decking about 18" from the lower edge of the roof and this vent is installed along the entire length of the roof edge, then shingles are put over it. It allows for an unobtrusive approx 3/4" gap between the shingles that allows air to enter, just as a ridge vent allows the air to escape). Sorry, I'm away from home ad don't have the magazine handy, but it looked interesting and might be a good approach for somebody who had no soffits AND was re-roofing their house.

 

[joesxm3]

Sam - that product seems like a perfect thing for me but unfortunately I have already had the re-roofing and have some sort of underlying water shield that goes four feet up the roof to protect from ice dam water seepage so cutting it is probably not a good idea.

Good news on the project front. The old part of the house is two feet wider and one foot taller than the new part. This makes working in it easier by a surprising amount. The workmanship on the old side is much better so I have had very little caulking to do.

So far I have managed to finish more than half of the old side so I can see the light at the end of the tunnel. I have also made arrangements to give some of the left over old insulation to a guy at work who needs to insulate the ceiling of his three-season room and is looking to save money so he will make due with the less than perfect old insulation.

Tomorrow is the last dump day of the year so I am taking a load of scrap and trash and hopefully buying the last two or three bundles of R19 batts.

I think that I may be having the problem with the hands that you mentioned. My right arm has been hurting and the fingers have been going numb, not to mention lower back ache from all the crawling around. I am going to suspend work for a week or so to give the old body time to recover.

Being out of shape and 52 is not the best recipe for manual labor. But as was said - "whatever does not kill you makes you stronger".

I think I will enjoy the winter rest once this is finished.

 

[ls99]

Great work. I went thrugh similar excercises on two previous and current house. IMHO sealing cracks with caulk and foam, is the biggest PITA, but in the long run pays the most benefit. Since insulation in and of itself does not stop airflow.
Reduction in air changes per hour pays off big time by not re-heating infiltration air.

Cheers. Then snuggle up in a nice warm house and enjoy.

By the way: I also foil taped all holes, and sealed with foam around all of the attic/ceiling mounted electrical boxes. You would be surprised at the amount of airflow through and around them. Also sealed cable, pipe feed through hole in sill plates of attic and basement.

 

[joesxm3]

I have been lucky that most of the electrical boxes were already sealed, but I do have a lot of non-standard pipes and wires above the bathroom that was remodeled by the previous owner. I am saving that for last since it is a lot of sealing and custom batt cutting.

I have yet to mention the two sky lights in the bathroom. I suppose we will need to discuss those at some point. I suspect that they are big heat loss areas. I had considered putting some sort of plastic or foam panel insulation on them for the winter, but I am worried that I will trap moisture.

That will probably be a project for next year along with painting the ceiling with the laquer mentioned by samclem.

 

[ls99]

Re: skylights. If you like the looks, some pain (heat loss) maybe worth having. That said, you might try a piece of polycarbonate cover on the outside, (top of glass), sealed at the edges. Would give another R2 or so, if glass is double pane -total of R4. Hey, that's a 100% improvement.

 

[joesxm3]

Not a bad idea, putting something on the outside.

Sounds like a job for me and Mr. Duct Tape - At least a half-assed attempt for this season and then something better next time.

The back ache continues, so I think I must have pulled a muscle by leaning over and lifting the plywood crawl-on pieces. Once I recover I have to clean the gutters, so while I have the ladder out I will attack the outside of the sky lights.

 

[samclem]

Polycarbonate could reduce heat loss somewhat, but you are likely to get water trapped between the plastic and the glass at some point (water that leaks in and can't get out, or water vapor that condenses on the cold side).

I'm not a big fan of skylights in general (deliberately putting a hole in the roof and ceiling, heat loss issues, etc), and bathrooms are a special problem due to the humidity/condensation.
-- If the skylight is in a cathedral ceiling (no shaft, no lower ceiling) then probably the best thing to do is to assure the skylight is a very good one (seals tight, double- or triple-pane depending on the temps, low e glass, argon filled, insulated frame, etc). A cheap stopgap that might last a couple of years would be one of those plastic heat shrink film interior insulating kits sold for windows--the trapped air is probably worth R-2 to R-3 or so.
-- For a skylight with a shaft and a flat ceiling, I'd lean toward forfeiting the view up through the top and settling for the light. Paint the shaft glossy white, put a frame in the ceiling to hold a sheet of white prism plastic, and tape a thickness or two of bubble wrap on top (tip of the hat to T-Al--leave a few places for air to get in and out to avoid condensation). Leave it all so it can be opened up for access. If you want to be really slick, you could even mount the florescent bulbs for the bathroom up there and do away with the separate light fixture in the ceiling. Cut a hole up top and down below to allow cross-flow ventilation to the attic (or else the enclosed space will get too hot in the summer and there will be moisture problems year-round).

Or, just get a really high-quality skylight and call it a day.

 

[joesxm3]

I am happy to report that after nearly six weeks of work I have pretty much finished the attic insulation project.

I removed all of the old insulation, used some for stuffing around the edges and gave a lot to a coworker for his attic so I avoided sending it all to the landfill.

So far I have installed 103 R19 6 inch thick fiberglass batts and 26 rolls of 25 foot R30 9 inch thick insulation over the top of the batts. I have covered everything but a two foot boarded over crawl walk on the old side of the attic. I will probably get another roll or two to finish that off.

Thanks to everyone that gave advice, especially samclem.

My advice after doing this:

1) Realize how much work you are getting into. Rolling the insulation over the batts was pretty easy, but removing the old batts, caulking and installing new batts was a lot of work.

2) Get a good set of knee pads. Once you get the hang of it, kneeling on the floor joists is much easier than trying to move around pieces of plywood to sit on.

3) Watch out for repetative stress injury to your hands from crawling. I had problems with my hands going numb and my arm hurting. Hopefully this will clear up as samclem said it did for him.

4) Watch our for hurting your back by lifting things while kneeling and bent over. I must have used my back like a lever lifting plywood and ended up out of action for nearly a week.

5) Give some serious thought to using blown in celulose fiber insulation instead for fiberglass batts. Most have said it would be much easier (and I now believe them) and others have said that its insulation capability does not degrade when the difference between inside and outside temperature increases as fiberglass does.

 

[samclem]

Wow, great work. Don't forget to seal up the attic acccess door/hatch, and maybe add some cheap foam to the back of it to prevent a cold spot from developing in your nice, highly-insulated ceiling.

FWIW, here's my patented method for estimating the time needed to complete a home improvement project:

((My estimated time) x 2) ^2, then express as the next highest unit.

E.g After reading about insulation in a book, a person might think it would take about a day and a half to roll out new batts and get the attic done. As we all find out, there's all the unanticipated stuff (caulking, stepping through the ceiling, haulng all the old insulation away, several trips to Home Depot, if we are lucky just one trip to the ER, etc). The formula takes all that into account:
(1.5 days x 2)^2 = 9, then expressed as the next highest unit (weeks) = 9 weeks. So, by getting this job done in less than 5 weeks, you finished in about 1/2 of the realistic time. Congratulations.

I hope you'll be happy with the insulation. It made a big differenc in our house (only the new windows have made a bigger difference in the comfort level). And you'll be saving money from here on out. Woo-hoo!

 

[joesxm3]

I am on track for the attic hatch project.

My friend Juliusz at work has already paved the way by building a foam hatch cover for his attic. When I bought the 16 foam panels to insulate the crawl space walls and then changed my mind I saved two of them to make a hatch cover and to seal the ventilation opening in the crawl space during the winter.

I picked up some construction adhesive suitable for use with foam and will be using some old wood paneling that I found in the attic to glue the foam to to make the hatch cover.

The basic plan is to make a two layer piece that matches the size of the hatch opening giving R20 insulation. I will then make some six or eight inch side pieces. Once the cover is in place I will use some sort of bungie cord or wire to secure it to the sides of the hatch opening. I may also but some sort of weather stripping on the bottom to seal it better.

I also bought some shrink-wrap for my windows. Although they are new replacement windows with double pane and inert gas between the panes I figure that the extra plastic and trapped air will help on the windows in the rooms I do not use. I have honeycomb blinds on the windows in my den so that helps insulate them better.

The sky lights are a mess, but that will have to wait until next year. When I was up cleaning the gutter last week I determined that they are simple single pane of glass units and must be a total heat leak. I will give thought to removing them and putting the roof back or to replacing them with some modern units.

So far the crawl space temperature vis a vis the running of the wood stove has been working out. When the outside temperature is 30 the crawl space is 47. This is with a four inch opening in the ventilation area. Juliusz says that once the ground freezes it will be colder because it is now benefiting from heat stored in the gound. I have been burning the wood stove and it is working out well.

I now keep my house around 60 for the oil burner and burn wood in the den while I sit there for four or five hours at night. Hopefully the crawl space temperature will remain above freezing and I can continue to burn the stove. I have piled a huge amount of wood on my back porch, so it would be a real bummer if I have to give up on the wood stove in the middle of the winter and then carry all that wood back to the shed in the spring.

I am turning into a real Paul Bunyan. I had offered a fallen tree to my neighbor who burns a lot of wood and has a big chain saw and a wood splitter machine. Last week he came over and sawed up the tree but his back was hurting and he told me that I could keep all the wood but I had to go buy a wood splitting mall and split all the wood myself. That combined with the electric chain saw my step-father loaned me has been quite an adventure.

So far between reducing my thermostat from 70 to 60 and with part of the attic having the new insulation and some being open while working on it I seem to have cut my oil consumption in half - 60 gallons vs. 120 gallons at the same point last year.

I am sure that I am exagerating, but with all of the advice I got here and all the experience I got from the attic project and working with an electrician on an electrical survey at work I think that I could probably build my own house if I had a couple of helpers for the large stuff. If I ever get booted out of my j*b and have a lot of time on my hands I might try that or try to rehab some old house.

It is looking like the wolves of winter are on the doorstep, so with the attic project finished and the wood stacked on the porch I think I might be ready to settle in for the long winter.

With all of the losses in the stock market and the bad economy I probably ought to ratchet up the observable enthusiasm level at work and start busting my butt to make sure that they like me enough not to flush me out. The added benefit is that they run the heat at work so I can save money on my heat if I stay late at work.

My hope is that in a couple years the market will start going up again and then I can FIRE at the begining of an up cycle - that is as long as enough of the nest egg survives to make that possible.