12:31PM | 09/30/12
Member Since: 09/30/12
1 lifetime posts
My 1890 home has severe ice dams every year which I understand are caused by poor attic insulation, ventilation and air leaks from the floor below. I have already installed soffit (sp?) vents & ridge vents and I'm ready to start on insulating, but I face one really big problem. There are 4 large roof valleys (the house is shaped like a cross), and in these areas the are no vents and the rafters are such that they block air circulation. Ice dams are most severe here. So I need some ideas: is it best to air-seal and insulate the floor, insulate directly on the roof, or insulate the floor and also the valley areas directly leaving the rest of the roof alone? I have already identified many air leaks including the stairway up, but probably not all yet. I haven't found much on-line about roof valley problems in older homes. I also though about putting in fans but eventually we want to put 2 rooms in the attic so insulating has to be compatible with this.


01:38PM | 10/05/12
Member Since: 10/05/12
1 lifetime posts
Ice dams are caused by heat from your home melting the snow on the roof.

Where you chose to place your insulation is your choice.

You may choose to fix insulation between the rafters and below the rafters, this is a difficult task and it will require a lot of insulation. But if you do intend to have rooms in the attic, this is the only way to go. You must have insulation below the rafters, followed by a water vapor proof plastic sheet, finished with drywall. Are the attic joists strong enough to make the floor of a bedroom? HAVE YOU ENOUGH HEAD ROOM?
Adding steel beams etc will make this a very expensive project.

The alternative, insulate between the joists and below or above the joists, this uses less insulation.

From the points of comfort and cost, keeping the insulation as close to the present comfort zone as possible, not only uses less insulation it also saves money on heating.

You fully understand that a lot of the heat that escapes from your home is due to the stack effect and the passing wind that pulls the heat through your roof.

Ensuring that all holes into the roof are blocked is a priority, then insulate the access to the roof and make sure the access is water vapor tight.

A desirable feature is sheets of polystyrene fitted below the joists with a water vapor proof plastic sheet fitted below the polystyrene followed by drywall to finish.
This will solve you problem, but it is messy and takes time, it also requires an empty room below to work in.
If you do get round to adding rooms in the attic, then this will stop them from overheating.


Post a reply as Anonymous

Photo must be in JPG, GIF or PNG format and less than 5MB.



Post_new_button or Login_button

Melt a rainbow of crayons with a hairdryer for a funky and fun pumpkin. Beforehand, try painting the pumpkin in a bright c... Filling an underutilized area beneath the stairs is a smart way to save space. Doing so with a stash of wood, however, is ... The Audubon Society inspired wallpaper in this Adirondack-styled entryway will get you in the outdoor mood. Grab your coat... Chalkboard paint opens up endless possibilities for customizing your dresser time and time again. Use chalk to label the c... A fireplace in the bathroom creates the ultimate setting for relaxation. Homeowners often choose electric or gas over wood... Yes, a freestanding garage can become its own tiny house. Artist Michelle de la Vega has all the comforts of a modern resi... There’s nothing like a new set of cabinet hardware to refresh a room. The possibilities are endless: Go modern, rustic, or... A kitchen in a greenhouse—who wouldn't enjoy spending time in this light-filled space? Details that enhance the conservato... Chalkboard paint features prominently in this elegant yet unpretentious headboard design. Add a new message daily to reflec... Twine lanterns add pops of crafty—but sophisticated—flair to any outdoor setting. Wrap glue-soaked twine around a balloon ... The indecisive homeowner need not fret over choosing one (or even two) cabinet colors. The kitchen cabinets in this artist... Incorporate nature into your lighting scheme by securing a dead tree in a concrete mold and draping your pendant lamp from... Simple and striking, a couple of pieces of "lovingly used" furniture creates a special kind of charm. A weathered chair fo... The Infinite Artisan Fire Bowl from Eldorado Outdoor is made from glass-fiber reinforced concrete, and offered in Oak Barr... The vibrant green of Granny Smith apples make a beautifully natural alternative to the traditional evergreen wreath. Brigh...
Newsletter_icon Google_plus Facebook Twitter Pinterest Youtube Rss_icon