How much attic insulation to add to old house?

[pheoxs]

We put up drywall in the garage and the next step is to blow insulation into the roof, since we're renting the machine anyways I figure it's a good time to top up my house's roof as well. It's a split level house so two separate halves to the roof, each about 550 sq ft.

The higher side is about ~R25 at the moment and the lower side is about ~R40 as it looks like they added some during when they renovated that part of the house.

Rough math says it works out to about 80$ to add R10 insulation to a side. Would it be worth bringing it all higher to R60 or so for ~500$?

Other info:
1957 house, no idea how the wall insulation is. Furnace runs quite a lot in the winter but it stays relatively cool in the summer with all the blinds and windows shut so I think it's decent.
Roof has non-vented soffit as far as I know, though I've only checked a few parts (They put vented soffit over solid plywood for looks, dumb). Only gable end vents and then vents on the top of the roof.

[suntan]

Yes absolutely. It will materially lower your bill.

If all the current insulation looks the same then it was the wind that moved it around.

[ThePenIsMightier]

Do it.
Although I'd also consider buying one of those Froth Pak spray foam DiY things for the garage. Disadvantage is you can't top up the insulation in the rest of your house.

[msommers]

Worth checking to see if any Canadian government grants are available for certain insulation types.

[ThePenIsMightier]

Worth checking to see if any Canadian government grants are available for certain insulation types.

Oh shit, good call!! I should've thought of that.
Auntie Rachel paid for like $600 of my spray foam a few years ago. Totally worth checking to see if Trudeau has a program. Although I bet it only works in 9 provinces and 3 territories...

[oster]

fkn giver' on insulation. one thing i wouldnt cheap out on, esp for a few hundred $

[Tik-Tok]

Worth checking to see if any Canadian government grants are available for certain insulation types.

Don't you have to go through that entire "pre-inspection" bullshit for all of that now?

[Nufy]

Anyone topped up their attic blow in insulation recently ?

I have a quote of 1800 to do mine.

Wondering if its reasonable or not...

[suntan]

How much sq ft and from what base R value?

[pheoxs]

Anyone topped up their attic blow in insulation recently ?

I have a quote of 1800 to do mine.

Wondering if its reasonable or not...

I diy'd mine for about 400$. The Shawnessey Home depot rented the cellulose machine for free if you buy more than a certain number of bags of insulation. The bags are only 15$ a piece and I split 30 bags to do my garage and top up my house. It kinda sucked climbing in my attic and took a few hours but saved a fair chunk of costs. Mine was also slower because of a split level home being two separate attics.

It was a 2 person job as one person just sits outside and keeps adding insulation to the machine. And then you run the 100 foot hose into the attic and one person up there pointing the hose. I'd sacrifice a half day and getting messy for the sake of saving a grand but depends on how big your house is and how the attic access is.

One 25lb bag will do about 1" over 150sq feet (R3.5). If you want R35 then it'd do 15 sqft worth per bag.

[CarlLester]

Anyone topped up their attic blow in insulation recently ?

I have a quote of 1800 to do mine.

Wondering if its reasonable or not...


$3600. 2300 square feet. R50.

[ExtraSlow]

Anyone modifying their attic ventilation or air-sealing at the same time?

[Nufy]

1200 Sq ft.

Top up to R50

[mr2mike]

I've always debated opening up the attic airflow. Going on 12 yrs... Never done.

Got the same thing, vented soffit over plywood.

[Tik-Tok]

Anyone modifying their attic ventilation or air-sealing at the same time?

When we hired a company to add blow-in insulation, they also added these cheap shitty styrofoam sheets in the rafters "to improve airflow", but they were shit and installed shittily. When we had the soffits replaced, they did a much better job of making sure the attic had enough ventilation.

I still say the best thing I did for summer comfort was to install the powered attic fan. That was extremely noticeable when I first installed it, and the 2nd best was the addition of blow-in insulation, which made winters heating more efficient.

[suntan]

The styrofoam sheets are there to keep the insulation from covering the soffit entirely.

[90_Shelby]

The styrofoam sheets are there to keep the insulation from covering the soffit entirely.

This. As long as air can move from the soffit to the attic space, they’re doing their job.

I sympathize with anyone who has to install them in a finished attic space prior to adding more insulation. Horrible job, speaking from experience.

[pheoxs]

The styrofoam sheets are there to keep the insulation from covering the soffit entirely.


Yeah

https://www.homedepot.ca/product/owens-corning-raft-r-mate-rigid-extruded-polystyrene-attic-rafter-vent-22-5-inch-x-48-inch/1000503435

[mr2mike]

Older houses will have cardboard for the same purpose.

[Tik-Tok]

I know what they're for and how they're supposed to work, but when it's just kind of shoved against the rafters and don't meet up with the existing vent space, they don't do anything. The soffit guys laughed their ass's off when they opened up the existing vents and couldn't find any of the foam until they started digging through the insulation.

[suntan]

You weren't kidding when you said they were shitilly installed.