The folks I bought my house from stored a lot of things in the attic. Because of this, they had removed much of the insulation, put down plyboard, and stacked boxes on the board. I barely use my attic and I’d like to replace the insulation before it gets much colder. I know it comes in rolls…do I just take it up to the attic and unroll it? Does the “paper” side go up or down? Anything special I need to know besides wear goggles, gloves, long pants, and a long-sleeved shirt?
Paper side goes down. However, they probably left the insulation between the joists. That insulation should have a ‘faced’(paper)side already. If so no need for further faced insulation. You should get un-faced and roll it out perpendicular to the joists. In general the thicker the better. I’d just leave the plywood down and roll right over it unless you want the plywood for some other project.
Do not stuff insulation into the the rafters or on top of the soffits. Most houses have soffit venting and that needs to remain clear so airflow can travel freely.
Wash with cold water after you are done.
Only step on the joists. Do not step in between the joists. It may look solid but that is only the backside of 1/2 drywall, your foot will go right through it.
Avoid stuffing insulation in direct contact with lighting fixtures(the back side), unless you know they are rated for direct contact.
I would go with blown-in insulation. Way less hassle. Hardly any climbing around in the attic. It is often just cellulose, so much less hazardous to breath than rock wool or fiberglass batt. You can rent the blower and do it yourself in half the time you would spend with batt. You should really at least get a quote from some local pros, it may be more affordable than you think and will only take about an hour for them to get the job done.
Insulation is miserable stuff to work with. Masks are a pain in the ass, and careful as you are, fiberglass is still going to get in your lungs.
We’re in the process of insulating our attic, too - I know my husband did a bunch of preparation work before we’re (finally) ready to put down the insulation. I’ll send him in here and see if he can explain what needs to be done before putting in the batts or blown-in insulation.
rolling down rolls like boytyperanma described is quick. leaving the plywood down will allow you to quickly and safely lay that down, removing the plywood and then only being able to step on the ceiling joists takes some effort.
wear gloves, goggles is good. use a dust mask too.
with either rolls or blown-in be careful not to cover vents or light fixtures (unless rated to be covered).
boytyperanma’s advice is ‘spot on’ correct. Another option is the ‘blown in’ type of insulation.
Places like Home Depot and Lowes will loan you the machine to blow the insulation upon purchase of a minimum amount of insulation.
A couple of advantages are that it cuts down on the amount of time to do the job, the amount of crawling around in the attic, and makes it easier to apply insulation in ‘hard to reach’ areas. You don’t have to drag all of those big rolls of insulation up the attic stairs (or worse, up a ladder and thru a ‘scuttle hole’.:eek:)
(Hint: The insulation is blown in thru a flexible hose, (usually about 4" dia.) tape the end of the hose to a long (a 10’ piece of 1/2" elec. conduit works well) pipe in order to extend your reach.)
The only disadvantage I can think of, is that it makes it a ‘two man’ job. One man working the end of the hose, and another outside feeding the insulation into the blower. 
Either of the options suggested in here will work fine. Fibreglass batts are a pain in the ass to work with and do require the full personal protective equipment setup mentioned upthread followed by a long, cold shower to wash all the fibre off you. Blown insulation, if that’s an option, is much easier and far less toxic if you’re using cellulose instead of blown fibreglass.
One thing to be aware of is how much you plan on using; if it’s an older home (and I’m guessing from your description that it is), there’s no point in going past R-30 for an attic – the structure is almost certainly too leaky to have much positive effect for you beyond that level of insulation. If it’s a more modern house – say 15 years old or less – you can aim for as much as R-45 in the attic and still get benefit. Anything more than that is just wasting money. Check the product you decide to use; typically there’s a label right on the packaging giving you information on how much material = how much of an R-value, so a minute of grade-school math will tell you how much product you need to add. For example, fibreglass batts provide an R-3 rating per inch of insulation thickness, if memory serves – so if you have 3" of insulation up there already, you currently have an R-9, so you’ll want to add another R-21, or roughly 7" of fibreglass, give or take.
Blown insulation is best if you want convenience and complete coverage, and no itching.
Read up on how to do the edges. I assume this is the attic area, fully vented, etc. Your soffit may have vents ( better have). when blowing insulation, or even laying rolls, you want to allow those to breathe, to allow any leaked moisture to eventually dry up. ( Assumes water dries up faster than more comes in). Usually there are cardboard pieces that you nail between the trusses against the roof so that there’s an air path from the soffit vent to the open attic.
Also be sure that if you use rolled insulation, you cover right up tight past the edge of the wall below, or to the cardboard vent paths. If not, you may get very cold top corners of your rooms. I agree, if the existing fibreglass under the plywood is still intact, lay the other stuff - no paper front - crosswise over the rafters to minimize pen chinks. Push it up nice and tight, cut and fit around wires, uprights, etc.
Modern construction usually in colder places now is - no paper-faced fibreglass, but the house interior is faced in plastic barrier so moist warm air does not leak into the cold zone. If you can see daylight into rooms through ceiling fixtures, etc - consider using plastic wrap or spray foam or something (depends on fixture and heat/fire issues) to be sure that no air is leaking into the attic. Leaking warm moist air (especially from bathroom ventilation) may simply freeze in a lump until the next warm spell, at which time it destroys the ceiling. Bathroom vent pipes should be duct taped and insulated all the way to the exterior vent so condensation happens outside the building.
Yes, be sure you watch where you are stepping if you take off the plywood. Falling through the ceiling will be messy and expensive. Stopping when you straddle the rafter will be painful.
This is correct in about 85% of the applications. In Florida and some other Gulf states and/or local jurisdictions, it might not hold true.
It’s astounding how many so-called professionals don’t know this, although I suspect they’re hiring day laborers who have not been properly instructed. We had to have our entire crawlspace re-insulated after an energy audit discovered that the insulation was in upside down (paper toward the ground), meaning we were getting the equivalent of about R-6 value, if that.
http://www.insulation-paint.com/vapor-barrier.html
Paper (moisture ‘barrier’) should face the living space?
If you live in an area where the climate is predominantly hot and humid the process is in reverse. As the humid outdoor air enters the walls to find cooler wall cavities it condenses into liquid water. Placing the vapor retarder on the outside will reduce water vapor movement from the outside from getting into the building envelope. Any vapor that does get into the walls or roof assembly can evaporate to the inside and therefore dry out before the moisture can lead to mold, mildew and rot problems.
Attics: Even when not required to prevent condensation problems, attic vapor retarders may be worthwhile; their presence may help maintain more comfortable humidity levels.
Check with a local builder to determine the correct placement or need for a vapor retarder. More detailed guidance on regional differences in moisture control recommendations can be found in the Moisture Control Handbook published by US Department of Energy . To guard against moisture problems, use Barrier Coat on interior walls and ceilings and provide adequate ventilation for the house. If you have a crawl space you should spray the underside with Hy-Tech #85 Barrier Coat.
How does the blown in insulation hold up if the roof leaks onto it?
It is better because you scoop out just the wet stuff and replace. With the rolls, you can’t just scoop it up.
A couple of points. Beware of multiple vapor barriers or onein the middle of your insulation. Some water vapor will make it past the first and can condense inside the second. Theories, practices, and codes vary. At one time, they weren’t putting vapor barriers in the ceiling.
They make ducts to go between the rafters and insulation. They come 4’ long and go at tha outer edge of the rafters allowing you to stuff the area full of insulation while assuring the important air circulation from the soffits to the vents at the top. Moisture WILL get into your attic. You need ventilation to avoid condensation.
One last point. My house was built in 1970 When we bought it in 1977, the joists were filled with a mixture of loose insulation and batts. Part of the center had plywood, which I added to. It is possible there never was any more insulation.
stores might have them using the term ‘rafter vents’.
Pain in the ass??? I think you are using them wrong ;).
Wisecracks aside: several have mentioned a long cold shower after using fiberglass. Why does it need to be cold? And do you really mean cold as in completely unheated, or do you mean tepid / body temperature?
I believe the common wisdom is that cold water will close your pores, keeping the fiberglass out, where hot would open them up and allow the fiberglass to get in.
The colder the better probably, but not so cold you immediately switch it back to hot.
I beginning to rethink this decision and pay someone to come in and do the blown in thing. I don’t have a man around the house and it sounds like either way, I’d need another person to help me out. About how much would that cost? Of course I plan on getting quotes, just curious. I live in central Alabama if that makes a difference.
I wish I could rent a husband for a day to take care of all these sorts of things!
Do not, do not use a mask! Get a resperator. Masks leak and you will end up with insulation in your lungs Get a good resperator and make sure it fits.
For a once or twice per lifetime event I think the mask is sufficient. Fiberglass simply isn’t that bad. If your working with it often the respirator is a necessity.