Home>Discussions>INSULATION & HVAC>100 yr old Attic - Poorly Vented, Poorly Insulated
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arlington1910
100 yr old Attic - Poorly Vented, Poorly Insulated
arlington1910

Hello,
I would like to add insulation to poorly vented attic in a 100 yr old house. This is in Boston, so it's cold winters and hot & humid summers. Currently the only insulation in that attic is some blown-in in the floor and who knows how old & compressed it is. The heating bills in the winter for this place are terrible - when the electricians did all their magic this summer I got to see inside the exterior walls and found that there is no insulation in the exterior walls at all! But I figure that since the attic is under-insulated and easily accessed, adding insulation to the attic would be a good, cheap, quick thing to do before winter & might provide the best bang for the buck. I would like to simply put in some batt between the rafters so I could still use the floor as storage space, though laying some unfaced batt insul on the floor would probably be more efficient. The issue is that the attic is not very well ventilated. There are no soffit vents, though a ridge vent was added about 10 yrs ago & there is one small gable-end vent.
What should I do?
Thanks!

Dobbs
Re: 100 yr old Attic - Poorly Vented, Poorly Insulated
Dobbs

I would recommend you consult the Yellow Pages under "Insulation" and locate an installer who specializes in blown in cellulose insulation, which is what you would need for the most expedient and low-cost way to insulate the exterior walls; they can even get the attic floor while they're at it---this would be better than trying to insulate the rafters; if the attic floor has flooring now, they can simply blow insulation under it; some special cautions would have to be taken to isolate any ceiling light fixtures.

Blown-in insulation is a great idea and a very good investment---the company shows up with a high-powered forced-air truck with a very long hose & does nearly all the work from the outside of the house, usually in one day.

They remove a shingle or piece of siding here & there & blow in the insulation into the stud cavities---ask them what "R" value they guarantee; get several estimates from at least 2 different companies.

The cost is usually a bargain---what it does is PAY FOR ITSELF over time in saved fuel bills and saved cooling bills----a gift that keeps on giving in all the future years to come.

You'll see a marked drop in your heating fuel usage; if you have AC, you'll see another drop in AC electric bills.

If there's no current flooring on the attic floor & you want to insulate the attic floor as a diy project, make sure you wear a dust mask--inhalation of fiberglass particles is bad for the lungs.

The vent issue can wait until the spring; you can calculate how much of a hole you need on each side of the attic gables if you Google "attic ventilation calculation"---another option is to install a ridge vent.

arlington1910
Re: 100 yr old Attic - Poorly Vented, Poorly Insulated
arlington1910

Thank you for responding,
Yes I agree - having blown-in installed in the walls would be an excellent project and indeed I would like have that done in the next couple years. Given the huge rewiring project that took place over the summer, another biggish project isn't in the cards at the moment (budgetary reasons, & that I'm still traumatized by the dust mess that it made). For this I'm really looking just for a weekend project I can do myself before the cold season comes - the attic, preferably between the rafters with fiberglass.
It does have a ridge vent, one gable vent (the other end of the attic abuts a bedroom & access is through a door off the bedroom), and there is also some blown-in in the floor of the attic under the wide plank flooring where you can see the blown-in through the gaps. I checked out what is needed in terms of how much ventilation - I just don't know if the configuration of one gable vent combined with a ridge vent is acceptable - from what I read it is not. I feel like I have to do something before winter arrives - to cut down on the heating bill & if nothing more to make the house more comfortable, but I don't want to make a mistake and open a Pandora's Box of new problems, or do something that I'll simply have to undo at a later time.
Thanks!

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