Replies

1. 
   reinvent | Aug 02, 2008 01:46am | #1

   You say it is falling down. Is it in between the roof rafters, or knee walls?
   Foam is best but spendy. If you think you will be in the house more than a few years I would seriously consider it. If you go that route have the rim joist done as well.
   Where are you located?

1. 
   Disputantum | Aug 02, 2008 02:25am | #2

   Rafters, knee walls, the gable-end walls. It's also in the first-floor stud bays, but I don't want to mess with those at the moment. I'm in NY.Which is the rim joist?Is spray foam reversible, and can they get it into closed-off areas?

   Edited 8/1/2008 7:29 pm ET by Disputantum

1. 
   reinvent | Aug 02, 2008 03:07am | #3

   Rim joist are where the wall framing meets the foundation."Is spray foam reversible"
   No once it comes out of the spay nozzle you can't push it back in.;-)"can they get it into closed-off areas?"
   There is a kind that can be pumped into holes drilled in the walls.http://www.retrofoam.com/

1. 
   Disputantum | Aug 02, 2008 03:20am | #4

   OK, thanks very much.

2. 
   Clewless1 | Aug 02, 2008 07:19am | #5

   Clarification ... the rim joist is the perimeter of the floor structure between the bottom of the wall and the foundation.

2. 
   Clewless1 | Aug 02, 2008 07:26am | #6

   cellulose is a reasonable choice for retrofit. for exposed wall framing (e.g. in attic areas, fiberglass or batts is probably your best option. Not sure what you mean by 'dense pack cellulose'. Cellulose is either blown loose or blown 'wet' ... wet for e.g. exposed wall framing ... loose for e.g. attic floors and enclosed ceilings.

   I've blown many existing walls full w/ cellulose ... dry ... drill holes inside or out and 'fill it up' you have to keep mental track of wall cavities ... drill above/below windows. If you have a dormer ... you MIGHT do the ceilings (sloped and flat) ... but may have to take care of blocking attic ventilation. Filling up these blind areas may or may not result in moisture problems. Foam even may cause problems if you block attic vent air flow.

   My advice ... take carefull stock of your particular condition ... ask others ... ask professionals ... see what is done in your area and what people seem to get away with.  

1. 
   reinvent | Aug 02, 2008 08:04am | #7

   "Not sure what you mean by 'dense pack cellulose'"Holes drilled in walls or mesh stapled to studs and cellulose pumped in to 2lbs per cuft.http://www.regalind.com/regal_wall.htm

   Edited 8/2/2008 1:05 am ET by reinvent

1. 
   Clewless1 | Aug 02, 2008 08:57am | #8

   OK ... so dry applied. Generally for existing construction ... a reasonable choice ... easy to drill and install ... you can install it yourself ... material is cheap ... often equipment rental cheap or free if you buy their cellulose. If applying in open attic just keep your eye on attic ventilation ... don't blow into restricted eave areas w/ out baffles installed to aid in attic/roof ventilation. Inexpensive, too. And it is a 'green' building material as it recycles newspaper products ... someone may differ w/ this because of the chemicals added for fire retardent.

2. 
   Disputantum | Aug 03, 2008 09:44pm | #11

   Thanks. Some years ago, there was a lot of argument here about whether venting was really necessary. Is that settled now? The roof on my house not vented like you describe, and I haven't seen any moisture problems. About 1/3 of it is exposed rafters, and the rest is covered with ceiling. I haven't been able to determine yet if the area over the ceiling is insulated, but I'll do some investigating next week.

1. 
   Clewless1 | Aug 09, 2008 04:55pm | #12

   There are LOTS of discussions about venting vs. no venting in ceilings. Many will say venting is necessary and others say it isn't.

   IMO, it depends ... on the situation and how you do it. Understanding the science is key to whether you get away with it or not. Venting is about getting rid of moisture. Most situations, the moisture comes from within the house. If the moisture is 'allowed' to go into the attic, the RH rises (in winter) dramatically if you don't ventilate. Then it finds a cold surface (underside of roof sheathing) and condenses ... bad news, dude. If you seal your ceiling well, and have no penetrations ... cracks/holes around/in J boxes, wires, piping, etc. and a good vapor retarder, then you may get away with it (and people have).

   Recessed lighting and lots of J boxes in the ceiling can pose problems ... which are common situations w/ modern designs. If you have exposed rafters and look at the underside of the roof deck/sheathing, then you likely don't have many issues or concerns because there is no place to TRAP moisture.

   Lots of other variables will affect whether venting or not venting is an issue ... like exhaust fans in kitchen/baths, 2-3 story design affecting the stack pressure of the house, mechanical/pipe chases that go up through the house to an attic/ceiling space, leakiness of windows (allowing the house to rid itself of moisture that might otherwise go into your attic). Changes in the variables can result in creating a problem where non existed before (e.g. installing quality windows and caulking their frames).

1. 
   Disputantum | Aug 20, 2008 09:19pm | #13

   A belated mucho thankos. I decided to do the work myself.

3. 
   salbuild | Aug 02, 2008 08:53pm | #9

   I had a blower door/ IR camera analysis done of my 1850's house, and the blown-in rock wool insulated walls passed with flying colors (done in 1954), nice and tight, no missed areas, no settling, well insulated.  The ONE wall that was "new" before I bought the house was fiberglass batt, and was the ONLY wall with "leakage"/ low insulation properties throughout the wall.  It was clearly visible in the IR camera views that a greater amount of cold was seeping through the fiberglass batt insulation, that's not to mention the 1' x 2' area half way up one stud bay were the fiberglass batt apparently was compressed a bit and was letting cold air pass right by it and creating a cold spot on the interior wall. 

   Call around, there are still companies that install blown-in rock wool insulation.  It doesn't burn (being a by-product of the steel industry), is "green" since it is otherwise waste(LEEDS points), insulates very well, doesn't settle, or absorb water and is inert.  I don't sell it, but I believe in it as a very good insulation, better than fiberglass and cellulose. 

   The easiest and fastest fix for you may be applying a new barrier to hold up the insulation you have.  Wear old clothes and a respirator when working with any insulation.  Fiberglass is bad for your lungs, new or old (and doesn't insulate very well in real applications), and with any old insulation you should wear a respirator, not because of the insulation, but because of the decades and centuries of dust that is in it.  Also look for darker areas in your insulation- that's accumulated dust from air leakage.  Seal the holes with caulk or foam before re-installing the insulation.  

1. 
   Disputantum | Aug 03, 2008 09:35pm | #10

   Thanks for the info. It's reassuring that the rock wool is a good insulator. I have some idea of what to do now.