Insulation quandry

[dawoodguy]

I get ice dams and drafts. I've had 2 Insulation contractors in my Cape Cod style home and received 2 very different proposals. 1st one said they would insulate the walls with blown in fiberglass but no foam in the basement along the plate or floor joists. He said he can't get to all the areas so it's not worth it. And it's too hard to get to the roof too he said. The company has been around 30+ years. Second one (38 year company) said forget the walls, lets foam the basement plate etc (he said he sees no problem being able to get to the areas to do this and was surprised the first contractor said they could not do it).then pull the drywall out of the roof in the storage areas on each side, put channels in for air to circulate and foam over that....basically creating a cold roof. The drafts around the plate in the basement are very bad and the ice dams can get pretty bad too. What should I do? Who do I believe?

[EatenByLimestone]

Get a 3rd one. That way you have 3 different ideas on how to do it.

[MKepke]

The second proposal sounds more rationale to me. The first proposal doesn't seem to address your concerns : ice dams and drafts from the sill plate+ rim joist.

Hopefully that proposal includes adequate soffit ventilation.

I would expand 'fixing the drafts' to include fixing air infiltration issues throughout the house..leaks around windows, doors, electrical boxes on outside walls,...

But if you don't have adequate insulation in your walls, you should be considering that too. For which I would prefer cellulose for its anti air infiltration properties.

-Mark

[John Mihich]

I would think a cold roof would help in ice dams. I don't get any on this house - lots of venting. The old house I had ice dams right under the vents - the attic was warm also. So from my 2 experiences I would go with cold roof.

[BacsiBob]

I have not seen a Cape Cod house with adequate soffit ventilation. I suspect this is because the design was prevalent before central heating and the upstairs spaces were probably not much warmer than the roof/attic space. Most have two gable vents and that's it.

Ice damming is the result of heated air melting ice/snow on the lower portion of the roof. This creates a flow that is captured by the ice/snow at the very edge of the roof where it has not melted. the standing water can penetrate beneath the roofing and cause leaks.

The "cure" is to prevent heated air from reaching the roof. A house with an overhanging soffitt provides surface area for vents. Combined with a ridge or other form of roof venting, a natural air flow results.

Add the baffles, which allow attic insulation to fully cover the attic floor area without occluding the soffit vent, and you prevent heated air from reaching the underside of the roof.

This natural air flow also results in a cooler attic during the hotter months.

I don't know of a way to get adequate soffit venting in a house of this style. The rafters usually end flush with the outside wall and the fascia board that encloses the rafter ends usually has a gutter hung on it.

[Robert Adams]

thooks said:

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[blockquote]dawoodguy said:

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What should I do?

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I'd hire an Architect that specializes in residential construction. Get him to take a look, write a report/spec/narrative on the method of insulation, provide some sketches and have him inspect the work during/after completion.


With that method:

1. You have a licensed professional who has some skin in the game with him backing up his 'design' with a professional registration.
2. He is your eyes and ears (owner's agent) who is capable of determining a correct path and will report to you on the quality of construction.
3. He will possibly help you negotiate a fee/contract with a suitable insulation contractor.

I would not solely and blindly take recommendations from contractors on this problem/project.

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[/blockquote]

Engineer not an architect. Architects draw pretty pictures for engineers and builders to figure out hot to make it happen.

Course none of this is rocket science but it does take someone on site to make an assesment. Nothing new to insulation contractors.

[MKepke]

An engineer would be overkill too.

While I still think the OP is correctly focusing on the right issues first, he might benefit from an energy audit to further prioritize work on his house

https://nyserda.energysavvy.com/start-yo...?s=contact

-Mark

[dawoodguy]

Thank you for your suggestions....maybe an energy audit would be the way to go 1st. :-)

[Estrogen Hostage]

Never met an architect that was overly knowledgeable about venting.

My house has chases for air flow under the sheathing, then spray foam over that. That is what I would do too.

[PhilJoines]

Sounds like the first guy wanted the easy way out.