Hemp insulation

sculptor

Has anyone used or have opinions on hemp insulation for dry lining?
Or hemp plaster?

lastbuilders

I used it in my timber frame selfbuild and am very happy with it. My brothers and I had many long hours putting it into every space we could. A bit of a chore but worth it in the end. It is not irritating to touch and use so we didn't need any protevctive equipment which helped.

House is 2700 sq ft and heating and hot water (wood pellet boiler) last year was about 600 euros which I think is quite good. Also have HRV and got house very airtight during construction which I think is equally as important as the type of insulation.

Lastbuilders

sculptor

What depth did you use.

lastbuilders

190mm in external walls and 220 in attic.

Lastbuilders

Builderfromhell

I am also very interested in Hemp insulation for it's Hydroscopic (hope I spelt taht right) qualities.
Could you tell us ;
1. How does price compare to say Rockwool ?
2. Where can it be sourced ?

lastbuilders

I didn't price against rockwool but it is a good bit more expensive than fiberglass.
I got mine from ecological building systems in Athboy.

Just to also add that I know someone who works for the company as well as being a satisfied customer as per posting guidelines.

Lastbuilders

Builderfromhell

Builderfromhell wrote: »

(hope I spelt taht right)

that *


*sorry couldn't resist it!

sinnerboy

hygroscopic

couln'r resit taht :pac:

Mellor

sinnerboy wrote: »

hygroscopic

couln'r resit taht :pac:

Yeah, sinner is right on spelling, but don't worry, its never spelt correctly.
I mean I have seen it spelt wrong maybe 15 times here, but only once correctly.
Hydroscopic is still a word, just nothing to do with insulation

sculptor

190mm is a lot off my little extension.
Has anyone got any other hygrostatic solutions. ?
Is a solution hygrostatic?;)

Builderfromhell

Appreciate the Spelling lesson boys & girls. As a builder I only need good English when it comes to saying things like ;
'I didn't price for that, that'll be extra.'
'That wasn't on the drawings (or on spec.).
'We could have finished weeks ago but you changed your mind...' etc. etc.
'That slope in the floor is to allow flood water to escape'.

Still love to hear different opinions or experiences with hemp insulation.

lastbuilders

190m in external walls was made up of 140mm in frame and 50mm in service cavity.

Lastbuilders

sculptor

How does rockwool compare with hemp, do you need less depth?
And who supplies it?
At this stage it looks like I'll follow the herd and use pu.
When I took up the old floor there was white scummy fungus under the dpm.
there wasnt any between the drylining and old brick, I hadnt put a vapour barrier there. So I'm worried that if I put pu with a vapour barrier on the walls I'll end up with fungus there.
Which is why I'm looking for something hygroscopic.

Spartacus200873

Hi,

I am building an extension.

I am trying to compare RockWool and Hemp for insulation.

I am finding it hard to get a price for Hemp. How much roughly would 300mm insulation on a 40sq metres extension cost (standard pitch roof)?

From a U-Value point of view is Hemp worth it?

Many thanks.

Mellor

Spartacus200873 wrote: »

Hi,

I am building an extension.

I am trying to compare RockWool and Hemp for insulation.

I am finding it hard to get a price for Hemp. How much roughly would 300mm insulation on a 40sq metres extension cost (standard pitch roof)?

From a U-Value point of view is Hemp worth it?

Many thanks.

we had a hemp thread earlier in the week, im going to merge these two,

sydthebeat

Rockwool has a thermal conductivity of 0.38
Hemp can vary widely depending on type, moisture levels, humidity levels etc.
Hemps thermal conductivity can vary from 0.34-0.49 at 65% humidity.

Hemp has added advantages of being a better hygroscopic material, it also absorbs carbon, and as its a natural product theres a lot less 'embodied carbon' in its production.

sculptor

Thanks Mellor,
So Syd, how much hemp do I need to put inside a 230 solid wall (brick and block) behind membrane and sasamox to give me reasonable U values. Its a victorian house so I'm not expecting passive house standards.

sydthebeat

what thickness of sasmox???

I will assume a TC value of 0.4 for the Hemp.... (roughly half way between 0.37 and 0.45)

sydthebeat

230 masonry wall
25mm air gap between battens
105mm of thermo-hemp
13mm plasterboard

This make up would give you a u value of 0.27... which would be a reasonable value as it meets current minimum regulations for new builds.

sculptor

Thanks Syd, 143mm x 2 is a big slice out of a 3300mm room.
Do you still need the 25mm gap even though the hemp is breathable?
Sorry for all the tedious questions but the more info I have before I talk to the sales rep again.

sinnerboy

hemp is soft and can't be placed accross battens - must be between

better to spit 100 hemp thickness into 2 x 50mm layers

first layer between battens - horizontal
second layer between battens - vertical

FIRSTLY

apply breather membrane* to inner wall wall face - i.e. before battens and insulation

AND

use vapour check membrane* to warm side of insulation

the irish agent will for these materials* will give trade names that forum rules forbid me to post

don't sandwich cables between insulation layers

do sandwich heating pipes however - a nice detail is to have rad pipes "pop out" from wall not floor

sculptor

Is the supplier from the royal county and is he sound?

sinnerboy

yes - and seems to be . Made presentation at Homebond seminar in citywest hotel

and you can see mock up Cultivate Centre in Temple Bar

sculptor

Thanks Syd, Nothing like an excuse to go into town for a few hours.
Not like I'm busy I have to wait another week for the steel channels to go in, thats another thing. Are steel channels a cold bridge? I will have two each side of the room should I lag them and case in composite board?

We Are Leeds

.........

sinnerboy

sculptor wrote: »

Thanks Syd, Nothing like an excuse to go into town for a few hours.
Not like I'm busy I have to wait another week for the steel channels to go in, thats another thing. Are steel channels a cold bridge? I will have two each side of the room should I lag them and case in composite board?

bigtime

most definatley

sculptor

Had a look at that display, nice organic feel to it.
Next question, what happens to the moisture that penetrates the solid wall and reaches the breather membrane?
Does it trickle down and if so where does it go?
How do you fix the membrane without causing ingress and rusting your fixings?
If you take out a hilti nail thats been in a damp wall for a few years you know what I mean.
Someone tell me to shut up if I'm getting too tedious.

thinkofaname!

Hi, have build a wood frame, hemp and lime garden room over the last year. Got my hemp and an awful lot of help from a guy in Kerry. If you want details, I can PM them to you.

Builderfromhell

Does Hemp insulation have an IAB cert.? If not I expect it would be difficult to get a BER cert rating. or indeed a cert of compliance.

thinkofaname!

Builderfromhell wrote: »

Does Hemp insulation have an IAB cert.? If not I expect it would be difficult to get a BER cert rating. or indeed a cert of compliance.

Suffolk Housing Society built a couple of hemp houses, so there is a precedent, at least in the UK. That I know of, there is one new build hemp house finished in Ireland and at least two refurbishments.
There is an architect in Dublin who has spoken at a few things re hemp building. His name escapes me right now but if he is prepared to design, he should be prepared to certify.
From my experience, the problem with hemp plaster is that it is slow and weather is a big issue. But it is certainly not as toxic (speaking personally) as plasterboard and skim, although I still wear a mask and lime burns like hell!!

sas

thinkofaname! wrote: »

There is an architect in Dublin who has spoken at a few things re hemp building. His name escapes me right now but if he is prepared to design, he should be prepared to certify.

Patrick Daly by any chance?

I don't think this discussion is about a structural Hemp wall, its about HEMP as the infill insulation in a timber frame house.

Why are people so interested in Hemp , its shockingly expensive. Cellulose to me seems a better solution. It has similar properties in terms of breathablility and thermal conductivity but you can have it pumped in for less than half the equivalent u-value of the Hemp insulated wall.

The only reason i can see Hemp as an alternative to cellulose is that its reversible in that you can take it out and put it back in again. Possibly the only other reason is that there is a potential for cellulose to compress under its own weight over time whereas Hemp allegedly doesn't sag.

sas

There is a Hemp house in Co. Carlow which is apparently performing very well but can't be insured. Resale value must be taken into account too.

sculptor

It's for dry lining a victorian brick wall, thats why I'm thinking I need something breathable, the eco thing is a bonus.
Would the cellulose be suitable?

sinnerboy

sculptor wrote: »

Had a look at that display, nice organic feel to it.
Next question, what happens to the moisture that penetrates the solid wall and reaches the breather membrane?
Does it trickle down and if so where does it go?
How do you fix the membrane without causing ingress and rusting your fixings?
If you take out a hilti nail thats been in a damp wall for a few years you know what I mean.
Someone tell me to shut up if I'm getting too tedious.

not too tedious - tenacious but that all to the good

if the walls are very damp and waiting to dry them out is not parctical , then use pvc anchors to fix the battens . hilti the counter battens to the battens

a victorian red brick ought not be remain very damp - ensure

effective dpc is instatlled - dublin city council have banned chemical dpcs in protected structures which limits options

ensure footapths are 150mm below adjacent floor level to all places - use french drains if this is not possible

all pointing is sound ( lime mortar )

roof overhangs parapapets rain water goods are kept in perfect condition

windows cills are fully intact ( not cracked ) and intact dpcs under

to be very cautious i would seriously condider a temp insertion of timber frame type vertical joint vents - say for two years after refurb to allow absorbed dampness to migrate to atmosphre. remove and point with lime mortar then

sculptor

Sinnerboy, Good to talk to someone who has a good knowledge of old buildings and how to work with them.
Luckily we dont have much damp and I dont want to do anything to change that. I'm doing the repointing etc.
So should I go for breathable hemp/cellulose/sheepswool or pir/pu?
I dont mind loosing a bit on the u's if I keep mould and damp away.

sinnerboy

keep it breathable . you can't beat pu's for thermal performance , but this is not the only factor . because they don't breath you may well get nasty moulds behind them in this application .

hemp , rockwool , cellulose would be much better

bluemartin

Does anyone know where I can source bales of hemp in the Cork area?

BryanF

PM sent

wayoutwest

BrianF - I am looking for bales of chopped hemp (to add to my own lime plaster)to be delivered to Northwest region.I can get them from the U.K, but would prefer to buy from Ireland.
P.M me as well please.

Markcheese

Does adding hemp to lime plaster make much difference insulation wise? Or is it just to bind the plaster?

wayoutwest

I imagine that if you had a high hemp to lime plaster ratio, then you would get good insulation. I want to try adding a bit into my haired non-hydraulic lime plaster (as a binder) so I can hopefully increase the thickness of my backing coats from 15 mm to 25mm.I would say that even putting a small bit into the mix must also help with the insulation to a small degree .I have heard that if you make a real porridgy mix, then it is possible to get away with 40mm coat in one

BryanF

http://www.boards.ie/vbulletin/showthread.php?t=2056279105

bluemartin

wayoutwest wrote: »

BrianF - I am looking for bales of chopped hemp (to add to my own lime plaster)to be delivered to Northwest region.I can get them from the U.K, but would prefer to buy from Ireland.
P.M me as well please.

Hi did you manage to find someone who sells the bales of hemp in Ireland??

I was given a name for a guy down in the south west but I don't want to deal with him. I am aware of someone in the midlands who will order it in from the UK but he wants a number of people to join together in order to keep the cost down as sterling is particular high at the moment.

wayoutwest

Hi bluemartin - [snip] sell chopped hemp, as well as hydraulic,non-hydraulic(lime putty), tonne bags of the correct sand (needed for scratch and float coats) , and 20 kilo bags of the correct fine sand for the setting or final coat (three coat work).

bluemartin

wayoutwest wrote: »

Hi bluemartin - [snip] sell chopped hemp, as well as hydraulic,non-hydraulic(lime putty), tonne bags of the correct sand (needed for scratch and float coats) , and 20 kilo bags of the correct fine sand for the setting or final coat (three coat work).

Thank you very much, that is fantastic, much appreciated:) I will ring them later and hope they will deliver.

DOCARCH

Mod Note: Can we leave naming of specific companies/suppliers to PMs. Thanks.