reinsulating an old attic

John L

Hi to all. I am presently renovating an older house which was built in 1945.
The insulation consists of wood chips. My question is , should I just lay R25 insulation directly over these chips or can I lay down a vapour barrier first and then put down the fibre glass insulation. This house does not have and existing vapour barrier in place. I'm concerned that if I put the vapour barrier between the wood chips and the fibreglass insulation I may develope moisture problems. Would appreciate an educated opinion. Thanks.

Ron6519

If you have wood chips. I would probably remove them. I don't think mulch has alot of "R" value. Plus it burns and can harbor insects and rodents.
Install the insulation against the ceiling over a plastic barrier. It might be easier to blow it in as opposed to batts.
Ron

Maintenance 6

First, for the amount of space they are taking up, the wood chips aren't doing much for you. I'd get rid of them and use the space for more insulation. Second, I would install a vapor retarder. Either use paper faced fibreglas or plastic. If you use plastic, you cannot run it over the tops of the joists. You'll get condensation where the plastic is exposed to the cold air.

joasis

You didn't indicate your location, but cellulose insulation would be a far superior choice then anything fiberglass. Regardless of all the traditional though on the subject and the PR from Owens Corning, fiberglass has very little effective insulation value.

Remove the wood chips, lay a barrier if needed, and then get an insulator to blow it, or go to a box store and buy the cellulose and they will "loan" or rent the machine and DIY.

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Knucklez

i blew in loose cellulose in attick and walls (there was previously NO insulation in the walls at all!). no vabour barrier as there was none previous anyway. heating bill came down so much that i made the money back in one winter

here are some pointers to remember about blowing in your own insulation...

when the insulation is pumping through 100' of hose it builds up one hell of a static charge. it can be so bad that you feel noxious or light headed. also, i was wearing a watch that stopped working because of the static electricity build up. so take off your watch & cell phone!

also you must clean the air vent on the blowing machine every now and again.

the machine itself is heavey as hell. you probably want to leave it outside while you run the hose inside your house (or outside if you are insulating from the outside). so pick a day with good weather.

Knucklez