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Hi, I’m a new member with an old house. We need to reroof our 1910 Victorian cottage, and know that we need to go down to the rafters taking off two layers of shingles, and installing plywood over the framing, (2X4 on 24″ centres). The roofing company has suggested that we install ridge venting which I think is a standard suggestion. As our house is balloon framing and we use the attic space as living space, I’m wondering if this is a good idea. The house is in Vancouver BC, so we do get a cold winter (snow today which is untimely but here) . Does anyone have any ideas if this will make our house colder, or if other venting systems are preferable? Thanks in advance | |
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What sort of venting do you currently have? Also, do you have any insulation, and how/where is it installed?
Ridge venting is usually a good idea. Make sure your walls are insulated though because otherwise you'll have air moving everywhere and then you'll really be cold. If there's no insulation in the walls, you could go into the attic and put insulation in the top part of the cavities as to stop the air flow. Use fire block insulation like rotten wool.
Solid blocking at the top of the walls is really the best way to go to stop air movement. Stopping air movement into the attic from the living space can go a long way to alleviating any need for roof venting. In fact, in most climates, air sealing is more important than either insulation or ventilation. Some insulations can serve to block air - foam and cellulose, for example. Fiberglass is not an air block. Remember, it's used to make air filters.
BTW, with balloon framing in particular, if you vent the ridge without air blocking the stud cavities, it's entirely possible that you'll worsen attic dampness by drawing moist air up from the basement. I've seen this happen.
You've touched on an important and controversial subject whose answers depend on the house and the climate. To really get an understanding of this topic, which is rare even among experienced tradesmen, go to http://www.buildingscience.com.
Andy
"Never try to teach a pig to sing. It wastes your time and annoys the pig." Robert A. Heinlein
"Get off your dead #### and on your dying feet." Mom
Thanks everyone.
I think from the replies I received and the information in them, we will go with the venting we currently have, individual roof vents. Our walls are NOT insulated, we have plaster and lath and insulating the walls is not an option at this time. Also putting in blocking, whether it is with wood or other materials means that the ridge venting will be venting a very small area, which can be done with the smaller vents.
I now have some information to go to our roofing contractor with, so that I sound informed. This is a great forum for information!