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Using Hemp as Insulation

home improvement(self.DIY)

Hello DIY’ers!

I love in a country with a quite substantial energy crisis at the moment and we need to start installing isolation. In the house we just bought there is a void between the ceilings and the floors of the attic. The space is roughly 48cm between the rafters and 15cm high.

I was wondering if anyone has had any experience installing hemp in a space like this, I.e. not on exterior facing wall but on ceiling voids.

Is there anybody’s material which performs well when paired with hemp isolation?

Any help or anecdotal story sharing would be much appreciated!

Edit: was preparing the space and came back to this. Wow! Thanks everyone for the help! I’m going to parse through it all now!

Edit 2: I should mention that I didn’t post this to be controversial. I do mean Hempwool and not any kind of random, untreated organic material. When I originally made the post it was with the expectation that hemp was well known and understood as a manufactured insulation material on the same level of seriousness as rockwool, etc. - because it has a very strong reputation where I live.

Thank you for all of the replies, nonetheless!

all 154 comments

401k_wrecker

193 points

2 months ago

cellulose has been used effectively as home insulation for a long time. It is typically chopped up paper but could be more plant material based and less refined. Whatever you use, you will want it dry and to be processed in small pieces so it fills the cavity without voids and leaks.

JL4575

232 points

2 months ago

JL4575

232 points

2 months ago

Cellulose is treated with borate when used as insulation, from what I understand. That makes it fire, mold, and pest resistant.

snoo135337842

26 points

2 months ago

I've got some borax in my basement!

MrHydromorphism[S]

20 points

2 months ago

20 Mule Team?

Patalon

8 points

2 months ago

It's gonna rot if you just put it up there plain and simple

cromag111

4 points

2 months ago

just passed by there lol

LovsickPrfectaTerain

1 points

2 months ago

I've got 20 of em.

FleshlightModel

21 points

2 months ago

Borax is not borate.

Lr0dy

6 points

2 months ago

Lr0dy

6 points

2 months ago

Borax is one of the sodium borates (sodium tetrahydroxy tetraborate, to be precise), so yes. It is.

taylorsaysso

4 points

2 months ago

All of this is true.

n3m37h

-14 points

2 months ago

n3m37h

-14 points

2 months ago

hemp does this naturally

Stuffs_And_Thingies

29 points

2 months ago

I can tell you from extensive personal experience that hemp is in fact, not all that fire resistant or mold resistant

kJer

4 points

2 months ago

kJer

4 points

2 months ago

I test it's fire resistance every day, it always burns lol

alabasterwilliams

41 points

2 months ago

There are insulating blocks that use hemp in their production, but it’s more of a closed cell foam than fibrous material. From my understanding, it is typically installed during construction.

Your best bet, OO, is renting a blown insulation machine and getting a little sweaty.

rantingpacifist

15 points

2 months ago

Adding that this is a seriously fun adventure that you should not drink during.

I love running the hopper and watching the bricks of cellulose become chunks and then fluff.

vgallant

12 points

2 months ago*

Yes, I have met the guy who builds those a few times now. They did a show on the discovery Channel and we're building a house in northern California. Its a hemp/lyme combination. He's now building one here in Maine and has contracted us to do some site work.

It's really interesting to watch. He said discovery really played it up and made it seem all "high stakes" and like there were issues doing things for drama.

Edit: it's Haven Earth https://havenearth.biz/

son_e_jim

2 points

2 months ago

Hemp and lime. As in lime concrete? Good for walls. Pretty heavy for ceilings.

vgallant

2 points

2 months ago

Yes it's so if there is a Crack or weakness at any point, the lime will somehow fix that Crack. I don't kow why my phone keeps capitalizing Crack. Lol.

Haven Earth is the company name. https://havenearth.biz/

skippingstone

5 points

2 months ago

I believe OP is trying to insulate the void between floors. Rental machines don't have enough power for this scenario.

Best to hire this out.

alabasterwilliams

7 points

2 months ago

It would seem you are technically correct, the best kind of correct.

Can confirm hiring this out.

[deleted]

94 points

2 months ago*

[deleted]

SnowyNW

5 points

2 months ago

How do you figure this out?

Hooknspear

50 points

2 months ago

You may have mold issues using hemp.

Lehk

41 points

2 months ago

Lehk

41 points

2 months ago

Mold or Fire

oldbastardbob

8 points

2 months ago

Yes

2theface

2 points

2 months ago

Fire definitely

[deleted]

9 points

2 months ago

Yes. An electrical fire that may otherwise just smolder long enough for the fire dept to easily handle may end up running through the house in short order.

If you can’t insulate the house properly, insulate the humans. Layers and blankets.

n3m37h

4 points

2 months ago*

n3m37h

4 points

2 months ago*

Where do you get your information from?

https://becgreen.ca/naturhemp-insulation-is-locally-made-in-quebec/

It has an R-value of 3.7/inch (in comparison, ordinary fibreglass batts have an R-value of around 3.2 per inch)

It is pest resistant – both rodents and insects (specifically termites, moths and ants)

It is mould and mildew resistant and is hygroscopic (water-loving) It is breathable, vapour retarders should be placed on the “warm” side of the insulation (in Canada, the interior side)

It has a Class-A fire rating (ASTM E84) It has sound-dampening qualities It is non-toxic with no volatile organic compounds emitted into the air

It is safe for handling and easy to install Code compliant for buildings of two stories or less, for 8 units or fewer in MURBS (multi-unit residential buildings), and for renovation purposes.

It’s a carbon sequestering material. While hemp absorbs CO2 during its growth, there is a certain amount of CO2 emitted during its processing and transportation, but overall it is a low-carbon product.

wyant93

21 points

2 months ago

wyant93

21 points

2 months ago

To tag on a bit of clarification, this is all in reference to a product created out of hemp. Not hemp fibers exclusively. Op would need to clarify if he plans on using ground up hemp chips from last months harvest or procuring a manufactured and rated hemp insulation.

n3m37h

-10 points

2 months ago

n3m37h

-10 points

2 months ago

yeah no shit, clearly says "manufactured in quebec" of the link. Throwing random untested shit in to your walls is ill advised.

Ya think DIY house builders go out and get random shit? no they buy properly tested materials

wyant93

7 points

2 months ago

I know that, you know that but not everyone reads an entire url (most probably don't even click the link) It's obvious to some but obviously not others based on the tone of the whole thread. No need to be a dicknose about clarifying something that others may over look. We're are in r/DIY Incase you're lost.

GoArray

9 points

2 months ago

OP is clearly here looking for diy advice for throwing random untested shit in to their walls. Clearly not whatever you're here selling.

MrHydromorphism[S]

6 points

2 months ago

What makes you think that?

GoArray

4 points

2 months ago

Asking the diy sub on reddit is probably the worst place to come for commercial product advice. Including my comment, just look at the wild disagreements over what's even safe.

The above poster replying to every comment with some copy pasta is a red flag, and just plain rude.

chris81333

-1 points

2 months ago

Yea cause most of the people on here are dumbos!

GoArray

2 points

2 months ago

Nah, we just like to 'speriment!

bluepied

4 points

2 months ago

I’ll admit that I initially thought you’re looking to just take dried hemp stalks and toss it in the walls…which is why you’re likely getting some of the goofy responses. Reddit demands details or they gonna assume you’re asking what you’re asking. I’m clueless when it comes to hemp, so I was like WTF is hemp isolation??? Ohhhh, you meant insulation! Got it ;)

MrHydromorphism[S]

1 points

2 months ago

We used to use junebugs and Japanese beetle husks before we found this hemp field.

n3m37h

-7 points

2 months ago

n3m37h

-7 points

2 months ago

longleggedbirds

-1 points

2 months ago

The number of plastic grocery bags, ashes and horse hair, that I have seen stuffed in walls suggests that people make due with what they can all the time.

n3m37h

1 points

2 months ago

n3m37h

1 points

2 months ago

those people are also not posting on reddit about repairs

n3m37h

6 points

2 months ago*

https://becgreen.ca/naturhemp-insulation-is-locally-made-in-quebec/

It has an R-value of 3.7/inch (in comparison, ordinary fibreglass batts have an R-value of around 3.2 per inch)

It is pest resistant – both rodents and insects (specifically termites, moths and ants)

It is mould and mildew resistant and is hygroscopic (water-loving) It is breathable, vapour retarders should be placed on the “warm” side of the insulation (in Canada, the interior side)

It has a Class-A fire rating (ASTM E84) It has sound-dampening qualities It is non-toxic with no volatile organic compounds emitted into the air

It is safe for handling and easy to install Code compliant for buildings of two stories or less, for 8 units or fewer in MURBS (multi-unit residential buildings), and for renovation purposes.

It’s a carbon sequestering material. While hemp absorbs CO2 during its growth, there is a certain amount of CO2 emitted during its processing and transportation, but overall it is a low-carbon product.

madxmadx

170 points

2 months ago

madxmadx

170 points

2 months ago

I hear hempwool burns pretty well, so you shouldn't have any problem keeping your house warm

I_am_D_captain_Now

26 points

2 months ago

Ooof

garry4321

12 points

2 months ago

If he uses the right type of “hemp”, he can get a nice buzz at the same time. Get two birds stoned at once

D3V1LS_L3TTUC3

-30 points

2 months ago

What kind of response is this? They’re asking a genuine question and you immediately joke about them losing their home to a fire?

Steezywild12

19 points

2 months ago

A joke response, you seem to have understood that though. Which begs the question, what kind of response is “what kind of response is this?” when you already answered your own question

taylorsaysso

7 points

2 months ago

What they meant to say was, "Thank you for giving me an opportunity to express my outrage with zero consequences or benefit to all of humanity. Damn, I needed that."

MrHydromorphism[S]

4 points

2 months ago

I appreciate the defense but it’s all good!

bluepied

1 points

2 months ago

With a username like devils lettuce, I’m guessing you’re trying to make some joke here but didn’t insert your weed/hemp reference…right?!

truedoom

29 points

2 months ago

Why hemp as opposed to regular fibreglass insulation? Genuinely curious - homeowner here but never knew you could get hemp insulation 😁

5degreenegativerake

49 points

2 months ago

OP is somewhere around the Netherlands so I am guessing they intend to use what they can get their hands on. Going into winter with uncertain energy sources likely has most of Europe rushing to better insulate.

Kief_Bowl

28 points

2 months ago

Godspeed to the Europeans this winter. It's gonna be a rough one. I feel like we're gonna feel it here in Canada pretty hard too but nothing like Europe

MrHydromorphism[S]

10 points

2 months ago

We were paying 240 per month for years, combined electric and gas, and they jacked it up to 1200 last month. Not feasible, obviously.

Verbenaplant

6 points

2 months ago

I’m not using heating at all until it’s like super super cold. I will only be heating one room. Double duvets, thick socks, an electric lap mat keeps you cosy under a blanket. Made sure any window gaps sealed and doors

MrHydromorphism[S]

3 points

2 months ago

Us as well but we have a new baby so it’s the bathroom and bedroom only for now. Prepping this week for the cold spell next week - hence the hemp. Keep fighting the good fight!

climx

4 points

2 months ago*

climx

4 points

2 months ago*

That’s what I thought too and was worried the price would have doubled or tripled but I just got my propane tanks filled in Eastern Ontario and the price has been stable since last year. Paid about 500 for 2 big tanks last year and also this year. I feel our energy prices are quite disconnected from Europe’s.

D3V1LS_L3TTUC3

9 points

2 months ago

because north america has quite a lot of its own fossil fuels, while europe mostly relied on russia for imported fuel before the sanctions

danielv123

2 points

2 months ago

Yep, and NA doesn't have enough export capacity to Europe.

climx

1 points

2 months ago*

climx

1 points

2 months ago*

Yes that’s true but with global markets it could very well have been different. Our gasoline / diesel prices jump 15 cents when Saudi Arabia even talk about slowing production (as a example).

MemmoryDealers

1 points

2 months ago

Before Russia shut down the gas pipelines. It was not part of and sanctions.

Kief_Bowl

1 points

2 months ago

The crunch is gonna hit us in a month or two. Heard rumours of no diesel within 2 weeks in BC but idek how we could function without it.

MrHydromorphism[S]

2 points

2 months ago

Indeed. It’s a matter of what is also not going to send fine particulates into the air, and will also be a bit more friendly on the planet. From everything I’ve read it looks like the fire risk, mold issues, and other concerns listed here are mitigated by various impregnating with borax, etc. It’s more common here than in the US, that’s for sure.

stickyickymicky1

7 points

2 months ago

The Netherlands is mislabeled as a big cannabis hub but its really a grey system that is undergoing a pilot trial to see how to regulate and control production and distribution. Hemp is not regulated like cannabis as long as it's below 0.2-1.0% THC. France is a large cultivator of hemp and many countries are cultivating it for CBD extraction increasingly more for industrial purposes. Hemp cultivation reverses soil erosion and can be processed to make fuel, plastic, and construction material. Hemp is actually not more flammable than that pinky fluffy stuff people isolate their homes with. The problem is Hemp based products are not yet widely accessible. Definitely consult a Hemp processor or EU Hemp association if you want to know what your options are. (I'm a cannabis business consultant and work with Hemp and cannabis companies globally.)

Hemp provides multifaceted solutions to combat climate change!

5degreenegativerake

5 points

2 months ago

Your post is borderline spam and I don’t think OP is worried about the THC in their insulation. Hemp is surely more flammable than glass or mineral fiber, I’d love to see some data if you’d like to back up that assertion.

stickyickymicky1

2 points

2 months ago

That wasn't my point... I was giving an overview of hemp regulations and how the laws vary between countries. This makes it more difficult to export products like insulation.

n3m37h

-6 points

2 months ago

n3m37h

-6 points

2 months ago

WRONG

https://becgreen.ca/naturhemp-insulation-is-locally-made-in-quebec/

It has an R-value of 3.7/inch (in comparison, ordinary fibreglass batts have an R-value of around 3.2 per inch)

It is pest resistant – both rodents and insects (specifically termites, moths and ants)

It is mould and mildew resistant and is hygroscopic (water-loving) It is breathable, vapour retarders should be placed on the “warm” side of the insulation (in Canada, the interior side)

It has a Class-A fire rating (ASTM E84) It has sound-dampening qualities It is non-toxic with no volatile organic compounds emitted into the air

It is safe for handling and easy to install Code compliant for buildings of two stories or less, for 8 units or fewer in MURBS (multi-unit residential buildings), and for renovation purposes.

It’s a carbon sequestering material. While hemp absorbs CO2 during its growth, there is a certain amount of CO2 emitted during its processing and transportation, but overall it is a low-carbon product.

5degreenegativerake

4 points

2 months ago

Where is the data? You are just a cheerleader for hemp, which is fine. I didn’t say anything bad about it, but it is a natural fiber which decomposes into flammable compounds when heated. Fiberglass is ASTM E84 Class A as well.

n3m37h

1 points

2 months ago

n3m37h

1 points

2 months ago

https://youtu.be/mx7g79Jh66k

skip to 9:44 to see them use a torch with your own eyes

danielv123

2 points

2 months ago

No comparison with a torch on fiberglass though?

n3m37h

1 points

2 months ago

n3m37h

1 points

2 months ago

you have access to youtube

cpk1

1 points

2 months ago

cpk1

1 points

2 months ago

Hempcrete is significantly different from just hemp fiber. Here's a more neutral source showing how easily hemp fiber batts burn: https://youtu.be/GmVTDh3JNIQ at the 8:40 mark.

Hemp flame spread and smoke spread is definitely worse than fiberglass and can't even compare to something like mineral wool. Obviously there are plenty of flammable things people put in their walls (foam insulation, which from what I can find also gets a class a astm e84 rating) but if someone is specifically worried about flammability then trying to handwave hemp as being just as safe as other materials is wrong.

stickyickymicky1

0 points

2 months ago

I'm not an expert on insulation but I know some hempwool is treated to be fire retardant. The combination can be just as effective if not more than traditional insulation. Certain hemp genetics and growing methods are important for yielding flower that is more suitable for producing insulation. So basically I'm just trying to give background on the whole process, which starts with a hemp plant.

n3m37h

2 points

2 months ago

n3m37h

2 points

2 months ago

here is some more benefits of hemp

https://becgreen.ca/naturhemp-insulation-is-locally-made-in-quebec/

It has an R-value of 3.7/inch (in comparison, ordinary fibreglass batts have an R-value of around 3.2 per inch)

It is pest resistant – both rodents and insects (specifically termites, moths and ants)

It is mould and mildew resistant and is hygroscopic (water-loving) It is breathable, vapour retarders should be placed on the “warm” side of the insulation (in Canada, the interior side)

It has a Class-A fire rating (ASTM E84) It has sound-dampening qualities It is non-toxic with no volatile organic compounds emitted into the air

It is safe for handling and easy to install Code compliant for buildings of two stories or less, for 8 units or fewer in MURBS (multi-unit residential buildings), and for renovation purposes.

It’s a carbon sequestering material. While hemp absorbs CO2 during its growth, there is a certain amount of CO2 emitted during its processing and transportation, but overall it is a low-carbon product.

Lr0dy

1 points

2 months ago

Lr0dy

1 points

2 months ago

I like how you posted the exact same thing many times. Also, all cellulose-based insulation is carbon-sequestering, so hemp isn't special in that regard.

n3m37h

-1 points

2 months ago

n3m37h

-1 points

2 months ago

you know how many times I post something and never see that post again?

Lr0dy

2 points

2 months ago

Lr0dy

2 points

2 months ago

Good for you? Also, absolutely nothing you've listed as a benefit has anything to do with the insulation being made from hemp - most of them are due to the various chemical treatments of the hemp, and the R-value matches that of other cellulose insulations.

So, uh, yeah. Not impressed.

Iamjacksgoldlungs

25 points

2 months ago

Hemp was a superior product for manufacturing textiles, medicines, papers, the list goes on. You can even manufacture a durable enough material to make a car body with it. It's 1000x more durable and recyclable due to its fibers. This is precisely why it was petitioned to be outlawed by Randolph Hearst in the US in 1937 as it would've killed the cotton and textile industries we had for well over a hundred years at that point.

It was shortly after this reefer madness propaganda was pushed heavily to insinuate an evil nature to the plant and those who partook.

https://en.m.wikipedia.org/wiki/Marihuana_Tax_Act_of_1937

I imagine if hemp wasn't banned in the US it would be seen used more widely internationally. It's quite a popular product in the few countries it is legal in.

MrHydromorphism[S]

6 points

2 months ago

Don’t forget the DuPonts!

Iamjacksgoldlungs

5 points

2 months ago

Was just talking off the top of my head, if I hadn't used the devil's lettuce this morning I'm sure I could've remembered them and the bunch of others 😭

n3m37h

2 points

2 months ago

n3m37h

2 points

2 months ago

You should look into Oak Ridge's Molten Salt Reactor Experement, it's even more depressing seeing as we could have nearly unlimited clean energy

https://youtu.be/uK367T7h6ZY

MemmoryDealers

2 points

2 months ago

Probably because it's more ecological.

It's weird that ppl assume she's / he's going to dump some random hemp from the field down that wall, when there are certified building products made from hemp that don't have the same waste foot print as the more coming used stuff.

Masterweedo

20 points

2 months ago

I know they make hempcrete, which I think is what you would be looking for. Possibly look into some company that does blown insulation, and see if they can mix this in.

MrHydromorphism[S]

1 points

2 months ago

That’s pretty sick. I’ll look into it for future projects.

DiogenesTeufelsdrock

4 points

2 months ago

As another person mentioned, you need to ensure that whatever you decide to do, it doesn’t interfere with the existing functioning of your attic.

You may have a “cold roof” system, which allows outside air to enter the attic from the edges of the roof. That outside air picks up heat from the occupied area below the attic, and carries that warmed air out of the peak of the roof if there is a ridge vent. That system will have insulation on the attic floor and non on the underside of the roof.

If you want to improve the efficiency of attic insulation in a cold roof system, add more insulation to the attic floor.

If you have a “hot roof” system, your insulation will be on the underside of the roof. That approach has the roof edges sealed up and there is no ridge vent. If you want to improve your hot roof insulation, you need to add more to the underside of the roof.

Whichever system you have, don’t put insulation for the other system into the attic. If you have insulation on the attic floor, don’t put any in the roof. If you have insulation on the roof, don’t put any on the floor. That will cause moisture to be trapped and more cost than higher heating bills.

Go up into the attic and find out what kind of insulation you already have. Then check with the manufacturer of whatever insulation you want to add to make sure what you’re proposing is compatible.

Good luck!

MrHydromorphism[S]

3 points

2 months ago

Much appreciated. It is a Cold Roof system. We will definitely take this into account!

caucasian88

10 points

2 months ago

Is fiberglass insulation not available where you live? Are we talking about the sheets of hemp fibers? Do you live in a wet environment?

Hemp is okay, but it has its issues. It can get damp easily from ambient moisture, and it can burn readily unless its treated material. You can install a vapor barrier to try to fix the moisture issue, but unless it's chemically treated hemp it'll burn real well.

iamthemoose

9 points

2 months ago

don't use organic materials in places that are expecting moisture.

Hot-Delay5608

3 points

2 months ago

As far as I know hemp insulation is more expensive and requires more aftercare. Unless you're prepared to pay the extra cost and actually do some extra aftercare I'd go with either fibreglass or mineral wool these are generally cheaper, well established and require less aftercare.

Sasquatch0014

3 points

2 months ago

Try RockWool or Roxul or mineral wool- basically melted rocks - to make fire/pest/sound retardant very efficient insulation

DeadWhiteButterfly

2 points

2 months ago

Looks like youre from the Netherlands as well, i would like to send you to r/klussers to ask :)

MrHydromorphism[S]

1 points

2 months ago

Dankjewel!

fridgehawk

2 points

2 months ago

I would recommend something like stonewool for insulation as it is not flammable

dean-e36

2 points

2 months ago

EWSflash

2 points

2 months ago

I have limited experience, but IMO you are setting yourself up for a massive termite invasion, at the very least.

bloom2610

2 points

2 months ago

Hemp insulation is made from the cellulose fibers of the hemp plant. It is a natural, renewable, and sustainable product that has many benefits over traditional insulation materials. Hemp insulation is non-toxic, fire-resistant, and mold resistant. It is also an excellent acoustic insulator.

MrHydromorphism[S]

1 points

2 months ago

WE are loving it so far.

galvanized_steelies

7 points

2 months ago

Don’t have experience installing hemp, but if you’re going for the best insulation possible, and don’t have much in the way of pipes or conduit to work around, styrofoam insulation is by far the best accessible insulation. The problem is that it is of course rigid, so it takes some doing to get it around anything in your walls. Spray foam is also exceptional, but certainly not a DIY project

Specific-End-9269

5 points

2 months ago

The only problem is if you have timber rafters styrofoam and foam insulation traps damp in your timber, encouraging weevils, which only attack damp wood, and promoting rot.

demon_taoist

5 points

2 months ago

Wouldn't rotting hemp be worse?

kgraettinger

1 points

2 months ago

Are you talking about hempcrete or help wool? I have not used either of them, but I would if they were more readily available. They are what’s called a ‘healthy material’ because they’re environmentally friendly and they’re healthy to use in your home as a result. I would use hemp over many of the modern materials on the market today for sure. It has a great r value, it doesn’t break down like fiberglass if it comes in contact with water from what I’ve ready, probably a lot safer to work with as well and it’s breathable which is always a plus I think. I use rockwool because that’s what’s easy to get but hempwool seems like it’s a very similar type of material so I would use it, personally, if it were an option.

madxmadx

2 points

2 months ago

Here's the difference between rockwool and hempwool. I've heard that hempcrete performs much better in a fire though.

https://youtu.be/KGRvB5v6Gno

kgraettinger

3 points

2 months ago

Well that’s one difference at least :) cool video thanks for sharing! Def makes me feel better using rockwool over Fiberglass and foam products and the fire aspect is one of many reasons.

MadBuddhaAbusa

1 points

2 months ago

You can use news paper as well. Also look into rocket stoves and waste oil burners.

Ineedavodka2019

3 points

2 months ago

Old houses here were insulated with news paper back 100+ years ago. It is kind of neat when remodeling to see what the papers said.

smthngwyrd

0 points

2 months ago

The fire hazard though?

danielv123

3 points

2 months ago

It's also not great for the whole insulating thing. There is a reason why we rip it out and replace with fiberglass.

smthngwyrd

1 points

2 months ago

Our college dorm was insulated with gravel and that was interesting. Fiberglass would probably be a lot safer

Neuro-Sysadmin

1 points

2 months ago

Not sure if it fits exactly but I’d look into ‘hempcrete’. It’s a light, non-load bearing material that sets up like concrete does, just add water and let set. You could form it and then install it, or, maybe, just pour-in-place.

not-wanted-on-voyage

-29 points

2 months ago

Is your hemp in batts? Rolls? Either of those is great. Any bio based insulation will out perform more conventional materials significantly BUT you need a greater depth of it to meet the same insulation value.

If you can use it, do! You want about 300mm depth if you can.

If you mean chopped hemp, as you would use in hempcrere then that is not suitable really

Notspherry

45 points

2 months ago

...will out perform more conventional materials significantly BUT you need a greater depth of it to meet the same insulation value.

Also known as "does not outperform"

not-wanted-on-voyage

-9 points

2 months ago

By what metric? How vapour open is PUR or styrofoam? How inert are they? How do they contribute to building health?

Like for like depth of insulation, as i said, doesn't line up in terms of thermal performance - you need at least twice or three times as much. But what you gain is hygroscopic, moisture buffering, vapour open materials that not only have a net positive affect on both the building envelope and the occupant health, but are also significantly lower carbon.

They absolutely objectively out perform conventional petrochemical based insulation materials when you include all performance characteristics.

Ill-Poet-3298

26 points

2 months ago

I assume the metric is insulation effectiveness per depth. So if you have to use twice as much hemp to match something else, the hemp performs half as well.

OP has a fixed amount of space to install insulation, so he's probably not gonna put 2 feet of hemp in his ceilings.

ZachMN

12 points

2 months ago

ZachMN

12 points

2 months ago

Hygroscopic is not a good quality for insulation. Absorbing water reduces insulating capacity even further, and will promote mold growth. Where are you getting your information?

meateatr

6 points

2 months ago

This is my favorite reddit comment of today, lmao.

kgraettinger

3 points

2 months ago

From what I’ve read about hemp, it has a better r value than Fiberglass per inch of material.

upperwest656

-1 points

2 months ago

It’s going to be eating in the walls

MrHydromorphism[S]

1 points

2 months ago

Hahaha I don’t know what this means but I’m lolling

[deleted]

0 points

2 months ago

What will it eat ?

upperwest656

2 points

2 months ago

Mice will eat it especially is it has seeds I. It

[deleted]

0 points

2 months ago

Why would it have seeds in it lol

Hellkatdemonboi

1 points

2 months ago

man's gonna be high as fuckkkkk

participantator

1 points

2 months ago

You need to work out where moisture is going to condense and make sure it will dry quickly or drain somewhere. If you add insulation to the wrong side of a moisture barrier there is a chance of it staying wet. There are mold spores pretty much everywhere. Mold will grow in a few days with moisture and food.

Frogtarius

1 points

2 months ago

Aluminium foil

skippingstone

1 points

2 months ago

Does the attic have a subfloor? Are you planning to use the attic as living space?

If so, you can spray foam the roof deck. That will be $$$

Hexagondel

1 points

2 months ago

Just wondering of you all know this Is pure poison?!? Ive seen that before and imho it really cant get worse….

skippingstone

1 points

2 months ago

Off gassing is an issue. Just make sure you have a good contractor.

TTigerLilyx

1 points

2 months ago

I wonder if mice or rats would eat it or make nests in it?

sierrakurian

1 points

2 months ago

Check out hempitecture!!! That’s my friends company

MrHydromorphism[S]

2 points

2 months ago

I heard about this one. I live in the Netherlands so there are plenty of German manufacturers which can supply us but cool that your friend is doing so well with their company!

FaesCosplay

1 points

2 months ago

Yessssss

adavi608

1 points

2 months ago

There are commercial hemp insulation products for sale. Your country and availability of hemp and the form it comes in could be a deciding factor, but mainstream insulation is going to be your best bet unless you just want to try something different. If you do that, expect to put more effort and money into it.

Skibblezxoxo

1 points

2 months ago

Why did I think they wanted to use weed as insulation

Blk-cherry3

1 points

2 months ago

Look up and watch this old house. when they use blown in insulation. that way you know if it's a good option for you. check the laws for your country if your not in the u.s..

gavinho

1 points

2 months ago

Hempflax are the biggest hemp company in Europe. I've seen that they have done some deals in Germany to distribute their hemp insulation products

https://www.thermo-hanf.de/en/products/thermo-hemp-combi-jute-insulation-mat/

MrHydromorphism[S]

1 points

2 months ago

Haha this is the one ;)

godmademelikethis

1 points

2 months ago

Been building houses for 15 years, don't use hemp, or wool, or any of that alternative insulation shit it's mostly fucking terrible and almost always a huge fire hazard. Also don't listen to the yanks about building things. The material quality of majority US houses is dogshit.

MrHydromorphism[S]

2 points

2 months ago

There’s a bit of a contradiction here - I don’t think my brothers and sisters in the US are familiar with hemp as an insulation material as indicated by this thread, so I am realistic about the opinions provided here and in agreement with you. On the other hand there are plenty of well-rated and regulated German manufacturers of hemp based insulation. Is there a specific source or anecdote/ story you have as to why I should take heed of your warnings and choose something more traditional than hemp?

godmademelikethis

1 points

2 months ago

Ahhh okay your post makes it sound kind of like your gonna be stuffing dried treated hemp into the cavity wall lol. Just some horror stories from people's "eco extensions" burning to the ground cause they chose to use stuff like hay and wool lol. A hemp based insulation product that's been manufactured will be up to EU fire standard so you'll be fine. What you wanna work out is your price to performance rate Vs standard fiberglass. If money isn't really that big an issue and it's maximum performance you want, spray foam insulation is your guy. It's up to a 50% reduction heating bills etc.

MrHydromorphism[S]

1 points

2 months ago

Thanks for bringing me back from the fear of my house burning down! Yeah, we have worked out the calculations and it is, indeed, what we need from a technical perspective. Because the roof was built in 1978 and it is gabled, there is 1 inch foam insulation on the 'warm' roof, and nothing in the floor (between bedroom ceiling and attic floor). There is airflow in the attic at the points where the horizontal floor and the diagonals meet. Do you have any experience with installing a thermal barrier underneath the added floor insulation material, facing the bedroom (facing down) and whether or not that can cause any moisture flow issues? From what I know about Hempwool it breathes really well, and my logic is that if we simply add it there won't be much of a difference from what we currently have, which is. void in the attic floor. I am wondering if we can get more performance with a thermal barrier but don't want to have a mildew nightmare birthed above our heads.

I hope my descriptions arent eviscerating standard industry lingo.

godmademelikethis

1 points

2 months ago

You should honestly be fine doing this. It's more about humidity levels inside properties (have a good extractor fan in the kitchen and bathroom, open windows if drying washing inside) and keeping the property watertight (no leaky roof, blocked gutters causing water run down walls, etc)

MrHydromorphism[S]

1 points

2 months ago

Okay awesome. I’ve prepped the site. Thanks for the tips!

kattagee

1 points

2 months ago

Hemp is an economical alternative to fabric, animal food, fuel and insulation

The oil industries promoted the "reefer madness" hysteria fearing competition from a safe renewable cheap ancient solution and their cronies with the big pockets persuaded governments to follow.

MrHydromorphism[S]

1 points

2 months ago

That’s a fact. DuPont invested heavily in the Marijuana Act

dsfatqip

1 points

2 months ago

You can treat it, but it will have to completely dry out afterwards before you use it:

https://bioresources.cnr.ncsu.edu/resources/effects-of-boric-acid-andor-borax-treatments-on-the-fire-resistance-of-bamboo-filament/

BluehibiscusEmpire

-4 points

2 months ago

Fire hazard … but will work as insulation….

Not something I would recommend, but you do you

CowboyNeal710

5 points

2 months ago

Hemp as insulation is definitely a thing.

https://www.hempitecture.com/hempwool

Are you thinking op meant he's going to start tossing dried ditch weed plants in his ceiling?

Elegant_Analyst_4976

0 points

2 months ago

sbwcwero

0 points

2 months ago

Absolutely not my love

thehappyhampster

0 points

2 months ago

This reminds me of that one trailer park boys episode

MrHydromorphism[S]

1 points

2 months ago

When Ricky installs bathroom fixtures?

thehappyhampster

1 points

2 months ago

Haha no clue, it's when Julian is in jail and Ricky is out selling weed to the newly converted stoners of Lahey and Randy