How much insulation do you have? Is it enough?

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starting_the_dream
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Re: How much insulation do you have? Is it enough?

Post by starting_the_dream »

two minds are better than mine
Ain't that the truth! Thanks for taking the time to share your thoughts, Tora! Really great questions/ideas for me going forward and I'm sure others will benefit from them as well. Learning from someone who has gone through something similar can help each of us find the best balance regarding cost/time/materials for our projects.

This is our second winter in the house and most of the projects that had to be completed are done, so now it's time to work on improving quality of life issues. I'm also the type to fixate on a project, so at the moment it's insulation and heat loss. Sorry for hijacking the post!

One area that I've had to reorient my thinking on is that our first and second floor are not connected. We essentially have two separate units. In every other house I've lived in, both in America and Japan, the second floor sits on top of the first. But with this house, there is a large gap between the 1st floor ceiling and 2nd floor floor that is open to outside air. There are also large areas of dead space above the 1st floor ceiling, meaning the 2nd floor walls, while under the roof, have to be treated as essentially exterior walls for insulation purposes. You can see this in the attached picture. Most of that insulation looks ok, but some needs to be replaced. Also, the closet walls are not insulated. I would like to do that.

Regarding doubling up 50mm insulation: I've read some stuff that says if it's 'faced' insulation you shouldn't put it over existing insulation. The 'face' could trap moisture. This is the insulation I have. What say all? Should the insulation be 'unfaced' before laying it over the existing insulation?

I'll stop there for now.
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Zasso Nouka
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Re: How much insulation do you have? Is it enough?

Post by Zasso Nouka »

starting_the_dream wrote:
Thu Jan 23, 2020 2:47 pm
Regarding doubling up 50mm insulation: I've read some stuff that says if it's 'faced' insulation you shouldn't put it over existing insulation. The 'face' could trap moisture. This is the insulation I have. What say all? Should the insulation be 'unfaced' before laying it over the existing insulation?
I'm certainly not an expert on insulation but given how humid Japan can be it might be a good idea not to risk a build up of moisture in places that you can't easily see. Perhaps someone else will know more about the subject.

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Re: How much insulation do you have? Is it enough?

Post by starting_the_dream »

Instead of relying on websites and worrying, we decided to call the insulation maker for their recommendation. The insulation we are using is called アクリアマット. Here's the link to their homepage.

https://www.afgc.co.jp/aclear/aclear_feature.html

First off, they were very helpful. Given the general customer service in Japan, I highly recommend contacting the maker of whatever product you are using. Odds are it will be worth your time. Also, we only asked about アクリアマット and putting that over other アクリアマット insulation.

So, here's what we learned. First, this product was initially developed for walls. They seem to think their moisture barrier is special somehow. Because of this, they don't recommend doubling up in walls. According to them, the 'face' needs to face the interior and the 'back' needs to be to the exterior. If we want more insulation, they recommend buying thicker.

Second, this product will work fine for ceilings and the space between floors. Here it's not so important which side faces the interior. It will work either way. They recommend tacking it down if possible, but it's not necessary. Laying new insulation over existing is no problem. They didn't think there would be a problem with condensation. But if we were worried, we could cut slits into the underside of the second layer of insulation. But they stressed that they didn't think that was necessary.

I imagine that in walls, with the insulation sandwiched between two walls with little air flow, condensation could occur. Hence the 'special' moisture barrier. In the ceiling, since the insulation is simply resting on the ceiling with 'open' air above, moisture will be able to evaporate if it condenses at all.

I guess now there's no real reason not to get up on the second floor and use up the extra insulation just sitting in the barn! I know what my weekend plans are going to be.

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Zasso Nouka
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Re: How much insulation do you have? Is it enough?

Post by Zasso Nouka »

That's a good idea to go directly to the manufacturer and reassuring to know you won't have a problem later on.

Have fun over the next few weekends :lol:

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Re: How much insulation do you have? Is it enough?

Post by edmundedgar »

So when I found my place everybody told me it was going to be insanely cold. The house has this really awesome glass entrance room and bathroom which I didn't want to touch, but for everything else I was going to put warmth over period charm.

The house is quite well built for the era so the beams are awesome and it's built tough, but the walls were really thin (I think it's called 真壁) and there was nowhere to put insulation inside them.

Our builder's solution was to add an entire extra skin, with insulation in the middle This takes the form of a layer underneath the roof, a new layer of drywall on the ground floor, and a new layer of wood on the *outside* of the upper floor. Then it's all covered in shikkui so you can't tell the difference.


We also put in new windows, up there, which visually I don't like the look of at all, but I can't deny they're warm.

The upper floor is now *really* warm - new house type warm.

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Re: How much insulation do you have? Is it enough?

Post by Zasso Nouka »

That's a pretty good solution to the insulation problem, what type did you go for ? Do you have any pictures of the work in progress ? No worries if not.

It's nice to build up a list of different options and how folk think they perform, you can spend days reading through manufacturers websites and they all think theirs is the very best but having real world opinions from people that have had it fitted is far more useful.

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Re: How much insulation do you have? Is it enough?

Post by edmundedgar »

Zasso Nouka wrote:
Mon Feb 10, 2020 6:04 am
That's a pretty good solution to the insulation problem, what type did you go for ? Do you have any pictures of the work in progress ? No worries if not.

It's nice to build up a list of different options and how folk think they perform, you can spend days reading through manufacturers websites and they all think theirs is the very best but having real world opinions from people that have had it fitted is far more useful.
Here are some pics we've got in the ceiling, I think the inner walls are the same:


(It was too big to upload so I used imgur again - if it misbehaves you should be able to see it at imgur.com/gallery/JTTuZjA )

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Re: How much insulation do you have? Is it enough?

Post by Zasso Nouka »

The imgur gallery seems to be working fine this time, not sure what went wrong last time but it was probably phpBB's fault. Looks like you are using the same insulation as @starting_the_dream in places if I'm not mistaken.

Hopefully everything is warm and toasty up there now, is it something you'd recommend for other people ? Certainly looks relatively easy to install.

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Re: How much insulation do you have? Is it enough?

Post by Ibaraki llama »

We’re using the same insulation in the ceilings and walls, though we’re also putting an extra layer of insulated board over the inside of the existing walls. I wonder how well it well do, though I think we have to accept that the house will never be as well insulated as a modern home.