Basements, Attics and Crawl Spaces - Attic Insulation

I need to improve the insulation in an unfinished attic in an old (1927) brick bungalow. The attic floor has been covered in most places by wood planks (many are not nailed in place - just fitted well). In some areas and especially the areas closer to the eaves I can see a very old loose insulation - very thin in some areas. No noticeable vapor barrier just heavy wallboard for the ceiling of rooms below.

I am considering filling thin areas with extra loose insulation to bring to level and then running unfaced attic blanket (R-30 or 38) perpendicular. Thought about running it right over the boards.

Is this adequate? or do I need to be more drastic and remove the boards, remove the old insulation and start over with a faced insulation and then the attic blanket? (I would probably do this if I was staying here long term). Just not sure if it is overkill.

Opinions?

I have a similar problem in a 1924 house. Since they didn't use ridge & soffit vents, there is no way to insulate the rafters, without trapping moisture. In my case, I'm not going to touch what's there. I wouldn't risk breathing that stuff. I never knew about an "attic blanket" so I might look into that. Otherwide, I wouldn't touch it.

The place to start is in the home where the water vapour is created.
Water vapour comes from cooking, washing, breathing - if you have extractor fans in the kitchen and bathroom (preferably with heat exchangers) then the largest amount of water vapour will be vented to the outside. Opening a window for a short time will look after the rest. Water vapour always moves towards the coldest thing/area, so keeping the temperature indoors steady 24/7 does a lot to stop condensation. It is only when the temperature indoors drops that condensation forms on the nearest cold surface.
This is why attics become damp. Warm wet air rises from the comfort area in the home, through the ceilings and holes in the ceilings where light fittings wires and pipes are, into the cold attic where condensation takes place on the nearest cold surface.
The perfect solution is not to produce water vapour, the next is to vent it to the outside, the third is to line the upstairs ceilings with almost water vapour proof plastic sheet and or paint the ceilings with gloss paint or similar.
Holes in the home account for most of our heat loss, blocking all the holes saves on heat and stops water vapour getting into the attic.
Taking up the floor boards in the attic and fitting polystyrene sheets between the joists, is the best way to keep the heat in the home.
Four to six inches of polystyrene between the joists will save you money and make the home a lot more comfortable, placing the existing insulation on top of the polystyrene will save waste.

I will agree with Perry 525 to a point.

Perry has the right idea and lot's of gumption.

My thoughts are that a attic is a cold zone and you want to do several things with a cold zone.

The first one is that you want to properly vent it, which means that you want to have some sort of gable vent and you want to have some sort of ridge vent and you want to have some type of soffit that can vent from the bottom.

The rule usually is that you do not want to intake more air then you exhaust.

I live in a cold part of the country that gets snow and the worst thing is to have heat in the attic in the wintertime.

The snow melts off the roof and falls onto the lower roofs which are insulated. The water freezes and backs up under the shingles and ruins the lower roofs.

At the same time, if the main roof is not vented properly, the air is trapped inside of the attic in the summertime and it bakes the tar right out of the shingles.

With a old home, one thing you can do is drill holes on the trim board which will let fresh air into the attic and then cover everything with soffit and fascia.

Once inside of the attic, you can put up styrofoam baffles which lets the air reach the main roof, which allows you to run the attic blanket to the edge of the wall in the attic.

Any insulation project will involve some demolition and the first thing you want to get rid of is the boards in the attic.

Chances are the rafters in the attic are about a 2 x 8 or smaller and their main job was to hold tension on the walls and hold up the ceiling, not to be walked across or used for storage.

One way to minimize the loss is to have a thermal picture took of your home which would show you where the heat loss occurs and you can tackle that problem one step at a time.

What I would do is get rid of all the old insulation and shop vac the entire attic clean. Then I would have one of those insulation guys come to the house with the blown insulation that adds water to the mix. It takes about 9 months for it to dry and it sticks to the rafters and creates a more air tight seal.

Or I would have one of those Styrofoam guys come where they spray the foam insulation directly to the rafters - which drys and creates a permanent seal between the attic and the lower floor of the home.

Plastic is only good when it is put up properly. You have to Tuck tape all your seams and you have to use a acoustical sealant to the edges of the plastic on the floor of the roof to keep all air exchange from taking place.

You cannot just plastic the ceiling, you have to have one continuous piece of plastic from the floor to the ceiling, across the ceiling to the other side of the room - down to the floor again.

Regular construction adhesives drys out after a couple of years and the seal breaks and the air gets inside of the plastic and in the end, the insulation gets wet from the moisture that is trapped between the plastic and the insulation.

It's hard to explain, but easy to understand once you see it done.

The best examples would be on the TV show - Holmes on Homes.

On a similar vein, for an attic application, what are the advantages/disadvantages of using paper-backed fiberglass batts versus non-paper-backed?

The significant difference is that polystyrene is a closed cell insulation, this means that it comprises lots of tiny balls of air each surrounded by a thin layer of plastic.
The way it works is, heat on one side wants to make its way to the other cold side, but air is a very good insulation so the heat has a problem moving from one stationary bubble to the next. If the holes were larger than 16mm the heat would start to convect, rotating and transferring the heat from one side to the other.

Fiberglass on the other hand has an open cell structure where the heat passes through the glass strands and easily escapes to the cold. Worse, fibreglass is transparent to water vapour and water vapour moves through the fibreglass transferring both heat and water to the cold side.
Heat always moves to cold.
When it is freezing the water vapour freezes then thaws leaving the fibreglass wet and providing an express route out for your expensive heat.
You also have a problem that the passing wind pulls the warm air through the fibreglass.
Wrapping the fibreglass in plastic or paper helps to prevent the escape of heat, by suction but, you still have the transfer of heat from the surface of the paper or plastic.
However, it is impossible to make fibreglass a tight fit, so the heat still escapes through the gaps round the fibreglass, whereas you can cut polystyrene to a tight friction fit, even bashing it into holes that are slightly too small, it does have a small amount of give.