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swindmill 04-14-2010 01:08 PM

Insulation help in attic/half story
I purchased a 100 year old, recently remodeled home several months ago. It's a 1.5 story shotgun style house. The second story has a bedroom and a full bathroom. It has a relatively small unfinished attic space, where I am in the process of adding a walk in closet. I have read many threads on insulation and followed links to outside sources and read those, so I'm in the process of learning what I can about proper insulation, but I still have quite a few questions.

The entire house appears to have been insulated using rolls of fiberglass R-13 and R-19. As far as I can tell, the exterior walls were done with R13, but there is R19 in random places. I can't discern if there is a method to where the R-19 is vs. the R-13, but the house is built with a mix of original studs (2x5??) and newer 2x4s. I get the feeling that the insulation job done by the remodelers wasn't stellar, but the half story/attic space is really bad.

I've gutted the bathroom upstairs and it appears as though the ceiling in the side attic is insulated w/ R-13, and the knee walls aren't insulated at all. The 'ceiling' upstairs is a strip that's about 1 foot across ( /-\ ). There is recessed lighting there, and the remodelers simply did not insulate at all in the top attic, leaving a large amount of space uninsulated. A side note - there is a large faux vent on one wall that simply leads to the side attic...maybe someone can explain that, or tell me it needs to be filled. Another observation I had is that there is no insulation on the "floor" of the side attic, above the downstairs ceiling.

The unfinished area in the attic has loose insulation between the floor joists, but it can't be much more than 5" deep. There is no insulation between the ceiling joists. It doesn't appear as though the soffits are vented. There is one gable vent. I am in the process of adding a ~4x8 closet in this space, leaving side attic space on either side and about 3 ft. between the back wall of the closet and the front of the house (where the gable vent is).

After all that description, my question is what steps do I need to take in order to correct the existing insulation and how do I best insulate the unfinished space as I build the closet? It gets very hot upstairs while the downstairs stays very comfortable. Money is an issue, so if I can do this myself it would be preferable. The biggest issues I see are insulating the top attic without tearing down drywall and without getting near the recessed fixtures. I hope my description makes sense and thanks for reading through all of this. Any thoughts or advice concerning how to go about this and what type(s) of insulation to use are greatly appreciated.

AU_Prospector 04-15-2010 06:40 AM

Hey it looks like u have some work to do. My limited knowledge says three things from your post.
1) All your attic space, that is your interior ceilings (ALL) should be insulated to R38. Two layers of R19 will do it. First layer faced on the bottom, second layer unfaced. I think thats around 18 inches minimum if you use blown in fiberglass.
2) You cant have enough ventilation in your attic. You need to add some. Soffits are a must, Gable is good, the more the better. Maybe add an attic/roof fan to pull air up through your soffits and out your roof or they make them for gables too.
3) Dont block any flow of ventilation. If your closet project cuts your attic in half and blocks the flow of air, you should vent both halves adequately. Dont leave the other half unvented.

Personally I dont have enough insulation either so I have work as well. But my vents are good. I have a weird roofline with vents at each gable (5 vents). I also have two electric roof fans that click on at higher temps. I have ridge vents cut into the tops of my rooflines. Also my soffits are vinyl and perforated for ventilation. I am also careful not to block airflow from the soffits up to the crest of my attic. If I stand in my attic with all the lights off, I can see light all around me from the gables to the soffits. On a windy day its breezy in my attic. I think that is good.

swindmill 04-15-2010 06:53 AM

If I already have fiberglass rolls between the the roof and the drywall, is it possible to have more insulation blown in without tearing down all the drywall?
Also, I'm not mistaken in thinking that I'm limited in R value by the space available between the roof and drywall? Because ceiling height is obviously an issue in a finished attic, I can't feasibly lower the ceiling even if I went to the length of tearing out the drywall.

I have to look closer at my soffits to see why they aren't vented, or what's in the way. The outside of the house is newer vinyl siding over the old wood. I know the soffits are perforated on the outside, but something must be blocking them on the other side.

Perry525 04-15-2010 06:55 AM

Insulating an attic
1 Attachment(s)
A bathroom needs to be comfortable not too hot or too cold and as a bathroom creates a lot of water vapour it need to be ventilated.
I recommend that you do this job properly as water vapour can lead to wood rot.
You need to tear down the drywall.
And fit polystyrene or Blue Board between the framing, pack in at least four inches thick, and it needs to be a tight fit, between the rafters. No gaps or cracks.
Cutting it with a knife works OK, a saw makes even more mess.
Then fit a plastic water proof sheet over the framing taking care to overlap the joints and seal them.
This is to ensure that none of the water vapour gets into the wall/wood and starts rot.

Then fix another two inch thick layer of polystyrene over the plastic and finish with drywall. This last layer is to prevent the heat from the bathroom escaping by conduction through the wood, and it stops the heat from the sun coming in.

A temperature of 51C/124f on one side of a two inch thick piece of polystyrene will often result on a temperature of 38C/102f on the other, so you can see six inches of polystyrene should meet your requirements, with a drop to about 22C/70f.

It makes sense to do the whole attic to the same standard.

Then fit an extractor fan, one with an automatic shutter to keep out the wind and a built in humidistat that will turn it on as required.

swindmill 04-15-2010 07:07 AM

Tearing down the drywall in the bathroom wouldn't be a huge job, and I think I probably should. The Blue Board idea is a good one, although I'm not sure I'll have two inches to spare outside the rafters. Maybe five inches would be enough. What about spray foam? I understand that it has a pretty high R value per inch. There is a fan above where the shower will be that vents directly into a roof vent above the bathroom. Perhaps that helps with the rotting concern.

As far as the rest of the attic, it is quite a large space and replacing all of the drywall would be a big job for me, and certainly put me past the time period in which I was planning to finish the upstairs. If there is no good alternative, then I have to do what I have to do, I suppose. I will probably live in this house for 4-5 years, so not too long relatively speaking.

The part that I am finishing will obviously be done correctly from the start, but I need to figure out what correct, or even perfect, is for this situation.

AU_Prospector 04-15-2010 09:21 AM

can you add pictures? That would help

swindmill 04-15-2010 11:05 AM

Here's one of the bedroom and unfinished portion of the attic where the closet will be. I'll add better pictures, including the bathroom, later on today. Thanks for the help.

The wall between the unfinished and finished space (not pictured from unfinished side) is not insulated. There was an old chimney there, which I removed in order to put a closet entry way in. I'm hoping that correcting that will make a big difference.

Perry525 04-15-2010 11:38 AM

I accept that space upstairs is always tight.
I am sure that except on the hottest days and coldest nights 5 inches will be fine.

Spray foam is the best insulation (available) as it fits into every space and leaves no cracks for the air to be pulled through.
However, while it is quick and easy to apply, if you are on a budget you will find it very expensive.

The fan above the shower, venting into a roof vent is fine, if you can buy a humidistat to fit on to it....that's good enough.

The thing with fans is they need to pull the air from somewhere, so they can blow out the steam. Is there an vent for the air to come in?

Sorting a home and making it air tight and bringing the insulation up to date, when you are working, does take a long time. Best to do a bit when ever you feel like it.

Do keep in mind that there are millions of homes that are poorly insulated, badly ventilated and suffering damp and mould in twelve or so different States.

swindmill 04-15-2010 04:54 PM


You can see how the upstairs is likely insulated throughout from these pictures of the bathroom. The knee walls are not insulated, but the roof is, at least until it gets near the top attic space where it stops.

Perry525 04-16-2010 05:16 AM

I afraid the pictures say it all, the insulation is just not good enough by today's standards.
Where we are all trying to keep our heating and cooling costs down.
One really needs a bathroom to be comfortable, not too hot, not too cold, and cheap to run.
And R13 just doesn't do it.
Not only is the insulation poor, it totally ignores the heat loss/gain through the framing.
With six inches of polystyrene or Styrofoam, you have a situation where for most of the year the bathroom will be comfortable without adding extra heat or using the air conditioning.
Done once and done right, it will continue saving money for a lifetime, for you and subsequent owners.

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