Re-insulating 1980 walls, from interior or exterior?

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Parakyl
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Re-insulating 1980 walls, from interior or exterior?

Post by Parakyl » Sun Oct 07, 2018 6:16 pm

Our 1980 town home's exterior facing walls and the floors near those walls are crazy cold all winter. The exterior is the original vinyl siding, which appears to be in good shape (albeit dirty). The windows were redone by previous owners in 2011. The insulation in the walls seems to be very saggy, barely filling the space, and I'll take a guess and assume no house wrapping exists under the siding.

We're "ok" handy and are confident we could tear off interior drywall, caulk and spray foam and get some roxul back in, re-drywall n paint.... That's not the main issue. I'm just wondering, will that even really solve the problem? We wouldn't be able to do anything about the portion below the floor that has zero insulation or air sealing, so I'd imagine the floors would still be freezing. And would air still be pouring in through the nearly 40 year old vinyl at the joints maybe?

I know vinyl can last longer, but would it make more sense to get someone in and remove vinyl, plus the exterior siding, and replace the insulation from the outside? Then re-side and add house wrap, then new siding? Obviously way way more expensive, but with a new baby in the house maybe it's worth not living in a construction zone for the likely weeks it'll take us to diy it from the inside....

I know blow in insulation is often the go to, but I'm not sure i like that idea, it wouldn't really air seal anything, i don't see how it works with sagging lumpy old insulation already in there, and would be a massive PITA to remove if we ever want to redo the insulation properly in the future?

I'm not sure what is the right move, what's the "proper"way to do it that actually solves the problem and doesn't have us redoing work next winter?

Thanks!


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A. Spruce
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Re: Re-insulating 1980 walls, from interior or exterior?

Post by A. Spruce » Sun Oct 07, 2018 6:35 pm

The advantages of working from the inside will be that you won't have weather to contend with and you will be able to upgrade electrical, tv, phone, and anything else that needs updating after 40 years.

No matter how you look at this project, it is going to cost a fair amount of money to do, and you won't know if it will improve/fix the problem. I would recommend getting an energy audit done. This is where an infrared camera is used to find the cold/hot spots on the wall and locate where the actual leaks are coming from. You may find that the siding is the problem, not the amount of insulation you may or may not have. From there you could formulate your plan of action.
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Parakyl
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Re: Re-insulating 1980 walls, from interior or exterior?

Post by Parakyl » Sun Oct 07, 2018 7:58 pm

That's a good idea... Touching the walls and floors with my hands, the cold is everywhere, but I suppose worse near the windows... But really everywhere is ridiculous... If it's fairly even everywhere, is that siding? And if much worse in only some areas, insulation? Or vice versa?

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A. Spruce
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Re: Re-insulating 1980 walls, from interior or exterior?

Post by A. Spruce » Sun Oct 07, 2018 8:25 pm

There is no "rule of thumb" to know where the issues lie, that's why an energy audit will be helpful. Codes from 40 years ago were much less strict about vapor barriers, permeable membranes, and insulating requirements, so what is going on with your walls could be anything. It will also depend on how well your home has been maintained over its life. There are just too many things to list.
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Shannon
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Re: Re-insulating 1980 walls, from interior or exterior?

Post by Shannon » Sun Oct 07, 2018 9:36 pm

I agree here an energy audit will pin point the real trouble areas which I will assume will be more air leakage then insulation problems. House wrap really is more about stopping moisture that gets through the siding (vinyl siding is not water tight) from getting through to the wall sheeting and framing.It will slow some air movement but you need some air movement for proper drying of wall system also. The main culprit will be poor air/vapour barrier sealing or most likely of it if your home was built in the 80s. Those homes did not follow the strict standards that followed years later. Also the cold floors could be from no insulation and or air/vapour barrier in the rim joist area of the home.
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