# Attic Insulation



## Pano (Oct 16, 2012)

Thinking of adding the "blow in" insulation in our attic. 

We have a 3100 sq foot home. 2 floors. The house was built in '86 and in the winter, the second floor is cooler than the main floor and vice versa during the summer months. I'm hoping a nice thick layer of insulation will help with this issue. 

Does anyone have experience with this, and has it helped with heat loss and cooling of the house?

Thoughts and comments?


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## nobleea (Oct 11, 2013)

A house that age, for sure you can benefit from additional insulation. It may have been blown in originally, but settled over time. Or perhaps they used batts. You can certainly add a bit more to get back up to the right thickness. One thing to be sure is that the ceiling can handle the extra weight. Some contractors may recommend removing the existing insulation and then reblowing in new stuff. Fibreglass is lighter than cellulose for blowing in.

Its not expensive. I think we paid about $1/sq ft a few years ago to go from nothing to R-50 in fibreglass. R-40 is code. R-50 is a good option depending on what climate you live in. R-60 can be overkill except for the colder areas. Some of the ecohouses go to R80 or R100.


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## carverman (Nov 8, 2010)

Pano said:


> Thinking of adding the "blow in" insulation in our attic.
> 
> We have a 3100 sq foot home. 2 floors. The house was built in '86 and in the winter, the second floor is cooler than the main floor and vice versa during the summer months. I'm hoping a nice thick layer of insulation will help with this issue.
> 
> ...


I've had insulation blown on two occasions (2003) and (2014) to make it about R40??? (and how can you really tell with the amount they blow in?) to add to the existing R20 ( 6 inch thick fiberglass) that was installed when my place was built in 72.


My attic space is very tight crawl space(flat roof / approx 22 x 40 or 880sqft), so there isn't enough space for the insulation applicator to go in there to spray the cellulose the way it should be evenly applied.

Last year, they had to make 6 inch diameter holes in certain areas of the upper ceiling, then blow in the stuff in through those created holes into areas that was not accessible directly from the access hole in the master bedroom. Blown insulation will only go so far (about 8 to 10 feet in any direction) unless they can walk on the roofing joists.
In my case they could not get up there to do that so I gave them permission to cut out the holes and do
a proper job this time. These 6 inch diameter holes were repaired saving the original ceiling drywall cutouts.

The first time (2003) they did it they didn't get it into the corners of the attic where it was needed, so the
insulation job was incomplete. My roofers mentioned that to me when I had my mansard roof completely last year with 4 inches of styro-foam in the walls to replace the old loose friction fit batts on the studs of the upper walls.

Last September, I called the same insulation company back to blow in another R20 (6 inches plus) of loose cellulose over top of the existing cellulose that had settled over 10 years, and this time with 6 holes cut into the ceiling in strategic places to make sure the insulation got into the corners where it was needed.

Finally, after 10 years, I have at least R40+ in the attic and with this cold winter the house seemed a lot warmer.
My total cost to blow in the loose fill twice over 10 years was a bit over $2000.

I don't know how this additional application will improve the cooling of my house this year, but I remember
how dreadfully hot the upper floors were before the first application in 2003.
The A/C couldn't keep up on the hot days in June to August, running all the time.

After the first application of blown insulation, depending on where you set the A/C to come on,
it would cycle on and off a lot more.

I don't know how the latest re-application of 6 inches more of blown insulation last September
will help with the cooling this summer, but at a further cost of $1100, it should at least pay for the cost
of application over the next 5 summers (and winters) in electricity and nat gas savings.


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## birdman (Feb 12, 2013)

What a coincidence. Our home is 4200 sq feet (2100 on each level) and was built around 1984 and has R 30. Just upgraded to R52 for 1500.00 (blown in) and will receive a 600.00 rebate from Fortis. As it has only been 6 weeks since the work was done coupled with the fact that we just went to 2 tier electric pricing it will be difficult to see the savings but I figured I couldn't lose for 900.00. Apparently R 52 is where you should now try to get to.


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## carverman (Nov 8, 2010)

nobleea said:


> A house that age, for sure you can benefit from additional insulation. It may have been blown in originally, but settled over time. Or perhaps they used batts. You can certainly add a bit more to get back up to the right thickness. One thing to be sure is that the ceiling can handle the extra weight. Some contractors may recommend removing the existing insulation and then reblowing in new stuff. Fibreglass is lighter than cellulose for blowing in.
> 
> Its not expensive. I think we paid about $1/sq ft a few years ago to go from nothing to R-50 in fibreglass. R-40 is code. R-50 is a good option depending on what climate you live in. R-60 can be overkill except for the colder areas.


Blown fiberglass is better because even if it settles, it retains more air than the cellulose,which does settle over time. 

Application is very important. In my case, due to the design of the roof, access to the corners was not achieved in the first application, so there was some spots (corners and edges), where very little blown insulation was evident.
My roofers pointed that out to me when I had the roof and wall insulation completely redone last summer. 
I decided to call the insulation guys back and this second time insisted on a better job done.

*Here is a handy Rvalue calculator on blown insulation to give a better idea. *
http://www.lowes.com/cd_Blown+In+R+Value+Insulation+Calculator_477243886_


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## cainvest (May 1, 2013)

I did fiberglass bats myself, worked out to be free (except my labour) due to local rebates. One thing to be sure of, whether DIY or done by a company, is that your attic ventilation (soffit to roof vent air flow) is good and you have no air leaks from the house into the attic.


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## carverman (Nov 8, 2010)

frase said:


> Apparently R 52 is where you should now try to get to.


Agreed..but the problem is getting the applicators to blow in that much stuff evenly and uniformly. They just aim the hoses and go to it..one guy dumping in the bags into the blower and the other guy waving the hose around in the ceiling...not exactly that accurate, and they don't go up with a measuring stick to see how much got blown in.

This is the main issue that I had with the first application..which was still better than the existing R20 that the original builder put in 42 years ago, but certainly not R40 as the insulation guys claimed it was when they handed me the bill. 

With any blown insulation, there is a settling factor as well that reduces the R value over time, as the weight of the insulation squeezes out the air between the fibers. That TRAPPED air caught up between the fibers is what creates the insulation value.


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## Barwelle (Feb 23, 2011)

carverman said:


> Agreed..but the problem is getting the applicators to blow in that much stuff evenly and uniformly. They just aim the hoses and go to it..one guy dumping in the bags into the blower and the other guy waving the hose around in the ceiling...not exactly that accurate, and they don't go up with a measuring stick to see how much got blown in.


Depends on the contractor, as usual. The residential construction company I used to work for had the guys first go up and mark a line on the truss webs 12" up from the drywall, which is the thickness required for R40, and they had to make sure the lines were covered. That way we could be reasonably sure that the attic was getting a minimum of R40 throughout the whole attic.

So the thing to do would be to ask the contractor how they would make sure that you're getting the thickness you want. Or better yet, mark it out yourself, and check after, and maybe show them too.


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## carverman (Nov 8, 2010)

Barwelle said:


> So the thing to do would be to ask the contractor how they would make sure that you're getting the thickness you want. Or better yet, mark it out yourself, and check after, and maybe show them too.


Agree. That would be the proper way to do it...however, I have what they call a "Mansard Roof"..flat roof with small
roof trusses allowing about 16-20 inches of crawl space and no "walkway in the middle" that standard pitched roof trusses
allow. So a insulation guy cannot get in from the attic access to the ends of the front wall..he could get trapped in there
as there are nails sticking down from the roofing plywood.

In my case they just "guesstimate" based on the number of bags of loose fill and the approximate square footage of the attic area. That is why I decided for a second application and holes to be cut in the ceiling
so they could get at the hard to reach areas. 

Not very satisfactory , but these houses were not exactly your best construction either, back in that period.
Most of the houses in my area still have the original aluminium wiring..which requires a new electrical inspection each time the place is sold to satisfy the fire insurance. 

Ontario allowed that aluminium wiring to be sold and installed in residential back in the 70s. It was banned a few years ago, but the cost of removing it and replacing it with copper is an astronomical expense.


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## Barwelle (Feb 23, 2011)

Oh yea, I forgot about your Mansard roof after I read the thread. 

The other concern with that method is that they might over-fill in some spots such that there is no air space left for ventilation... I'm sure you know that in most attics, you need an air space that opens up to some vents, which serves to to prevent condensation buildup by letting air circulate to the the outside. If they happened to overfill right at a vent, or plug it up, that wouldn't be good in the long-term.


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## RBull (Jan 20, 2013)

This is likely a DIY project if you're at all handy. 

First off check to see what insulation levels you have. R40 is pretty well the standard now but many new homes go well beyond that 50+ although returns on investment diminish getting beyond 40. Obviously the greater the difference between this and yours the greater the benefit to you. 

My home built in '85 has R40 and no possibility of increasing that due to all vaulted ceilings/lack of air spaces with trusses. The house/garage addition I put on has R65 with blown in and my detached garage was a DIY to ~R65 as well- definitely overkill since its only heated to +2c. Also check to see if there is any prov, municipal or energy company rebate available to you before starting.

If you do it yourself just get a good mask, goggles and be sure to put up a stick to measure thickness as you top up. So some research on how ensuring you have ventilation panels/space open between soffit and attic space for airflow, along with cardboard/wood build up on attic hatch to prevent spillage into home. Or just get a good insulation co to do it and check their work. Good luck.


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## carverman (Nov 8, 2010)

Barwelle said:


> Oh yea, I forgot about your Mansard roof after I read the thread.
> 
> The other concern with that method is that t*hey might over-fill in some spots such that there is no air space left for ventilation... I'm sure you know that in most attics, you need an air space that opens up to some vents, which serves to to prevent condensation buildup by letting air circulate to the the outsid*e. If they happened to overfill right at a vent, or plug it up, that wouldn't be good in the long-term.


Yes. this appears to be what has happened. There was about 10 inches or snow and ice on the roof around
my gas vent. I still got my original 80% efficiency furnace, which is now over 20 years old and it requires a chimney vent to the roof.

Anyway, there was a terrific wind storm in December and the square metal flashing that supports the base of the
furnace gas vent, may have been affected as I had a leak coming down an inside wall in my kitchen right down to
the basement floor. 

Not a big leak..but enough it made the basement floor wet..thank goodness there was a floor drain around there. 

The water leak was a mystery since it hasn't leaked since I had the original tar & gravel replaced with
a membrane style roof in 2003..until this week!

I called my roofers from last year that did the mansard roof, and they came and shovelled off the snow and the ice dam
that had built up over the extremely COLD winter this year. 

The roofer found the source of the leak (at least he thinks) but was unable to fix it as the membrane needs a flame torch and tar to seal it and unfortunately his liability insurance doesn't cover use of a flame torch for his roofing jobs. 

However, he mentioned I really need an other square vent to vent the attic as the single (square) one the roofers put in isn't sufficient to vent the entire roof properly, hence the ice dam at the front.

Now I will need another roof vent installed as well, so I called the original guys that did the roof (with the flame torch), to fix it for me. They are an established company in Ottawa for over 80 years. so I know they will do a good job.

The other problem coming up is when I replace the existing furnace with a new high efficiency one in 2-3 years, the venting and chimney will have to be removed...another expensive roof repair at that time.


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## Beaver101 (Nov 14, 2011)

^


> ... The other problem coming up is *when I replace the existing furnace with a new high efficiency one in 2-3 years, the venting and chimney will have to be removed*...another expensive roof repair at that time.


 ... does the chimney have to be removed? Why not re-route the venting (to side of the house)?


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## carverman (Nov 8, 2010)

Beaver101 said:


> ^ ... does the chimney have to be removed?* Why not re-route the venting (to side of the house*)?


Can't do it now. The existing furnace cannot be vented through the side for some reason..It's about a 5 inch diameter aluminum vent that goes all the way through the wall in the kitchen to the roof. My "owned HWT" shares this chimney stack as well, so the HWT will have to be changed at the same time to a power vent model as the furnace is changed out. 

I think the exhaust stack temperature on these older furnaces is too high compared to the more modern high efficiency PVC ones that are available now.

I am planning on replacing the furnace before I sell the place (within 5 years), and then use the money to move into a seniors disabled access retirement place.
Right now, I'm not ready to do that.


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## cainvest (May 1, 2013)

carverman said:


> Can't do it now. The existing furnace cannot be vented through the side for some reason..It's about a 5 inch diameter aluminum vent that goes all the way through the wall in the kitchen to the roof. My "owned HWT" shares this chimney stack as well, so the HWT will have to be changed at the same time to a power vent model as the furnace is changed out.


Just change it when you get the new furnace to go out the wall and leave the HWT go out the chimney providing your local code allows this, mine did. Of course if your HWT needs to be replaced then you'll need either a chimney upgrade or go with a power vent unit.


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## Spudd (Oct 11, 2011)

I doubt you will get payback on a new furnace when selling the place, probably better to leave it and let the new people decide what kind of furnace they want.


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## carverman (Nov 8, 2010)

cainvest said:


> Just change it when you get the new furnace to go out the wall and leave the HWT go out the chimney providing your local code allows this, mine did. Of course if your HWT needs to be replaced* then you'll need either a chimney upgrade or go with a power vent unit.*


The gas vent was upgraded in 2006 and replaced with more modern chimney liner all the way to the roof ($700 at the time).
There is nothing wrong with the existing gas furnace which was installed in 1994. It has been working very well with no repairs other than an ignitor that failed a couple of years ago..but that is to be expected. 

( I replaced the inefficient old 1/2hp split phase motor fan with the new energy efficient DC fan motor (Evergreen) a couple years ago to save on electricity consumption. It seems to saving a bit, although with the cost of it (over $300 US and installation charge, it has set me back about $500, so I want to run it for another 5 years to recover the cost of installing it. 

Obviously the new furnaces have these kinds of motors already, so it would be of no use in the new furnace.

My HWT is now 15 years old, nothing wrong with it..trouble free all along and since I OWN it outright, I'm not about to throw out another $1500 to install a new power vent right now... or go back to the monthly rental situation again with the DE scammers, so I may just continue to use the old chimney once the furnace
is replaced for the new similar type (owned) HWT. 

I doubt that a new furnace/new HWT is going to bring me in any more money when it comes to selling the place while those things are always an incentive for the new buyer (no capital outlay), but that will be another $5k or so that I have to shell out, so I have to think carefully not to overspend just to fix up everything that the place may need at the time....just to sell it.

With the money, I get from the sale, I can go into one of these retirement places and hopefully afford the $1500 to $2000 a month they are charging for assisted living towards the end of life.


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## carverman (Nov 8, 2010)

Spudd said:


> I doubt you will get payback on a new furnace when selling the place, probably better to leave it and let the new people decide what kind of furnace they want.


Yes, I agree. The existing furnace is still working very well and has been retrofitted with a new DC fan motor to save on electricity, so there is nothing wrong with it ( well at least at this point after 20 years), but the heat exchangers are the main thing with these older gas furnaces. If they develop a crack, then that is pretty much it for the furnace..it's too old (80% efficient) to replace the heat exchanger even if it was still available.


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## cainvest (May 1, 2013)

carverman said:


> The other problem coming up is when I replace the existing furnace with a new high efficiency one in 2-3 years, the venting and chimney will have to be removed...another expensive roof repair at that time.





carverman said:


> I doubt that a new furnace/new HWT is going to bring me in any more money when it comes to selling the place while those things are always an incentive for the new buyer (no capital outlay), but that will be another $5k or so that I have to shell out, so I have to think carefully not to overspend just to fix up everything that the place may need at the time....just to sell it.


I was just commenting on your plan to replace in the 2-3 years you stated above but I agree that leaving that for the new owners is probably a good idea.


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## OurBigFatWallet (Jan 20, 2014)

My dad added some insulation to his shop (about 1,000 sq feet, 15 years old). To keep costs low he bought the insulation on sale from home depot and rented their blower and did it himself. One person feeding the insulation into the machine and one in the attic distributing the insulation within the attic. It took a few hours. He said it makes a big difference in keeping it warm in the winter (and cool in the summer). For anyone considering it I'd DIY, it's not complicated at all and if you do it yourself you can make sure the new stuff gets distributed evenly within the attic


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## Brian K (Jan 29, 2011)

If you are planning to DIY, one thing to watch for is that you don't block the soffit venting. My house (1987) has the aluminium soffit with cardboard spacers to maintain an air flow, but I have seen where insulation is sprayed to the eaves and it blocks this venting - which can lead to mold and insufficient attic venting. In that case too much insulation isn't a good thing. 

I also have a cabin that had plywood soffit with small 2" holes drilled along the eaves and screened covers to keep the bugs out. The previous owner added more bats of insulation to the attic and blocked this little bit of venting and caused condensation in the attic to form which dripped into the house and it also caused some mold to grow on the underside of the roof. I replaced the plywood soffit with the vented aluminium stuff, put in the cardboard spacers, then sprayed the under side of the roof with bleach and mould killer and it is pretty much gone now so maintaining proper venting is very important.


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## agent99 (Sep 11, 2013)

Lot's of good points in this thread. 

We added to our attic insulation a couple of years ago. For most of the attic, we had cellulose blown in over top of the existing fibreglass batts. It is the most economic way. But it is not good if you need to access the attic for maintenance or storage. In one area of our attic, we have our heat pump air handler as well as a storage area. There we used mostly fibreglass batts but under walkways, we used plywood covered styrofoam boards over the 6" joist batts. Overall, we aimed at at least R50 and ensured that by putting measurement sticks in several places. We used the preformed foam channels to prevent blocking soffit vents.

Although thicker insulation is a must, the major improvement we achieved, was by sealing all ceiling openings. This required removal of light fixtures and sealing the holes contractors usually hack in order to install junction boxes. Same around anything that penetrates ceilings or walls. We also found that the top of interior walls were not capped in certain areas. Anything like that creates a chimney like effect because the warm air will find a path to rise. We even plugged up and abandoned our wood burning fireplace chimney (which had other issues anyway)

Results were tested using Energuide Home Evaluation at time they were offering rebates. Our old home received a 73 rating (new homes should be in 80-100 range)


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## carverman (Nov 8, 2010)

agent99 said:


> Lot's of good points in this thread.
> 
> We added to our attic insulation a couple of years ago. For most of the attic, we had cellulose blown in over top of the existing fibreglass batts. It is the most economic way. But it is not good if you need to access the attic for maintenance or storage. In one area of our attic, we have our heat pump air handler as well as a storage area. There we used mostly fibreglass batts but under walkways, we used plywood covered styrofoam boards over the 6" joist batts. Overall, we aimed at at least R50 and ensured that by putting measurement sticks in several places. *We used the preformed foam channels to prevent blocking soffit vents.*


Blocking the soffit vents with blown insulation is a common problem and it restricts air circulation in the attic which ends up with ice dams, as I found out this winter, after having extra cellulose insulation blown in last fall.

In my case having a flat roof (mansard style) the attic vents that the builder installed was blocked off by the roofer adding new insulation. The extra blown insulation basically covered up the air coming up from the bottom of the mansard soffits and it caused some problems for me this winter.

I had to call in a roofing contractor to add another square vent to the front part of the roof. There was a square vent
already but it wasn't adequate enough with the extra insulation blocking off some of the soffit vents. 

I hope this will be enough as it is nearly impossible to crawl in there now with only about 16" of attic crawl space filled with insulation. 

http://www.ventilation-maximum.com/English/recommendations.html


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## agent99 (Sep 11, 2013)

Even with lot's of headroom, I am not much inclined to go into our attic areas that have blown in cellulose. We used to be able to lay down boards to walk on, but now all joists are buried and you have to feel for them with foot to avoid going through ceiling . Dust has settled down now, but still need mask and goggles when entering attic areas. At least the cellulose is not itchy.


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## cainvest (May 1, 2013)

agent99 said:


> Although thicker insulation is a must, the major improvement we achieved, was by sealing all ceiling openings. This required removal of light fixtures and sealing the holes contractors usually hack in order to install junction boxes. Same around anything that penetrates ceilings or walls. We also found that the top of interior walls were not capped in certain areas. Anything like that creates a chimney like effect because the warm air will find a path to rise. We even plugged up and abandoned our wood burning fireplace chimney (which had other issues anyway)
> 
> Results were tested using Energuide Home Evaluation at time they were offering rebates. Our old home received a 73 rating (new homes should be in 80-100 range)


I took advantage of that same rebate program, got quite a bit money back from it on insulation, a new furnace and air sealing. With older homes you do have to watch out how much "air sealing" one does unless you also install a fresh air exchanger like in R2000+ homes.


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## carverman (Nov 8, 2010)

cainvest said:


> I took advantage of that same rebate program, got quite a bit money back from it on insulation, a new furnace and air sealing. With older homes you do have to watch out how much "air sealing" one does unless you also install a fresh air exchanger like in R2000+ homes.


Humidity control is another problem. Usally too much humidity causing black mold..nasty stuff..you save heat of course, but then all the stale air inside has nowhere
to go. In my case with gas heat, I had the opposite effect...too dry during the heating season and static everywhere.
My house built in the early 70s never had a fresh air exchanger...just a 4 inch duct down by the furnace from outside.

I've lived in it for 19 years now, but thinking of having one like this installed in the fall...

http://www.rona.ca/en/exchanger-ea1500-air-exchanger


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## cainvest (May 1, 2013)

carverman said:


> http://www.rona.ca/en/exchanger-ea1500-air-exchanger


Exactly what you need if your house is sealed up really well. Those with old furances or regular gas hot water heaters will get some air exchange from those units from any air leaks in the house but if you plug all (or most) of those leaks up you'll need that unit you linked above.


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## agent99 (Sep 11, 2013)

cainvest said:


> Exactly what you need if your house is sealed up really well. Those with old furances or regular gas hot water heaters will get some air exchange from those units from any air leaks in the house but if you plug all (or most) of those leaks up you'll need that unit you linked above.


In an old home like ours, with no basement and built in-part in 50s and then added to in late 60s, it is hard to get the house sealed. We did everything we could and still only got a midling results when tested. Our heat loss reduction was the sum of reduced leakage and insulation of attic and crawl space walls (Spray foamed)

We were on 100% baseboard electrical supplemented by a small wood stove. We removed the wood stove and installed a high efficiency ducted heat pump (Mitsubishi). It keeps our home warm even when temperature goes down to -23C. After that, we supplement with some baseboard heat in one room. But very seldom needed.


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