Wood shavings & Lime Insulation - Help

Hi Folks,

I need to insulate some interior walls and floors. I would like to use wood shavings & Lime which I have free access to. So soaking the shavings in water, adding lime slake and then pressing it into panels in a template or directly onto flooring. Later off closing that layer off with solid flooring of 6 cm limecrete. I'm wondering why this is not more common. A lot of people use hemp and lime, but cant find much reliable information on wood shavings. I realize that any amount of moisture would cause fungal growth, but for my case it's very dry and anyway the insulation is closed in on both sides by limecrete.

Do any of you have experience with these materials?
Any tried and tested recipes?
Why are people not using this?

thanks in advance!

I have had nil experience with those products, together.
BUT, I have plenty experience with the situation you are dealing with and earth building.
Lime is used as an additive to clay to create a plaster that breaths.
Wood shavings are not high on the list of insulating product efficiency.
Hemp crete works best as a very thick medium.
Nothing you appear to be proposing will be of any benefit for insulating purposes.
What are you building and perhaps more information will help us?
I believe more modern materials may give you a better and faster outcome, since limecrete / plaster takes ages to dry.

Hi Max.
Wood shavings don’t provide a lot of insulation. Especially not if the cavities in between the shavings are going to be filled with lime.
That’s probably why it doesn’t get used more.

But if it will be in between 2 layers of limecrete why don’t you just pour it in without lime? Maybe just treat it with a bit of borax.

How is the limecrete going to keep the moisture out? Would you provide some more details of the 2 constructions you’re planning?

Count me as another hesitant to agree with this method.  Wetting and pressing of wood chips will not make good insulation , I fear. The goal is to create air pockets.  Perhaps use treated cellulose....technically a wood product of sorts....for the insulation area, I think you will achieve superior results

Hi John,
thanks for weighing in. So I'm doing a very dry, fluffy mix trying to emulate wood fibre insulation boards with what I have available.
There is just enough lime to bond the wood fibres together but leaving loads of air pockets in between.
I made a vid to explain better what I'm trying:

https://streamable.com/5ocwpr

So far I'm pretty happy with it. It's drying fast because we have 30 degrees at the moment. I'm sure it insulates less than industrial products, but that doesnt bother me.
Have a look at the vid, let me know what you think.
Cheers
Max

John C Daley wrote:I have had nil experience with those products, together.
BUT, I have plenty experience with the situation you are dealing with and earth building.
Lime is used as an additive to clay to create a plaster that breaths.
Wood shavings are not high on the list of insulating product efficiency.
Hemp crete works best as a very thick medium.
Nothing you appear to be proposing will be of any benefit for insulating purposes.
What are you building and perhaps more information will help us?
I believe more modern materials may give you a better and faster outcome, since limecrete / plaster takes ages to dry.

Hi Benjamin,

I tried that, but putting the limecrete on top of just wood fibres didnt work.
I'm doing a very dry mix, trying to trap as much air as possible.
It's very fast and free. If I lose some R value I can add 10 cm more (or as much as I want). Its really simple and light work.
Have a look, this is the experiment:

https://streamable.com/5ocwpr

Benjamin Dinkel wrote:Hi Max.
Wood shavings don’t provide a lot of insulation. Especially not if the cavities in between the shavings are going to be filled with lime.
That’s probably why it doesn’t get used more.

But if it will be in between 2 layers of limecrete why don’t you just pour it in without lime? Maybe just treat it with a bit of borax.

How is the limecrete going to keep the moisture out? Would you provide some more details of the 2 constructions you’re planning?

Forgot to mention what I'm doing.
A large floor area of an old house 2nd floor. The previous owners had put concrete flooring down. Its breaking apart and uneven. But structurally fine.
So the idea is to insulate it, add metal grid on top and then pour limecrete over it.
I will finish with cocciopesto, which is a very smooth lime finish.
The space is dry and covered.

John C Daley wrote:I have had nil experience with those products, together.
BUT, I have plenty experience with the situation you are dealing with and earth building.
Lime is used as an additive to clay to create a plaster that breaths.
Wood shavings are not high on the list of insulating product efficiency.
Hemp crete works best as a very thick medium.
Nothing you appear to be proposing will be of any benefit for insulating purposes.
What are you building and perhaps more information will help us?
I believe more modern materials may give you a better and faster outcome, since limecrete / plaster takes ages to dry.

The size of the shavings/chips/sawdust matters. A little Portland will help it hold together for the walls.

This is awesome thanks! Wow!

p

R Scott wrote:The size of the shavings/chips/sawdust matters. A little Portland will help it hold together for the walls.

the hempcrete binder is a mix of hydrated lime and hydraulic lime ,sometimes an extra dash of wood ash , this mix sets up a lot quicker than just the hydrated lime by its self , might help in the process---as was the suggestion of some portland cement to be added.