Poplar as insulation

[Squaredy]

I am starting to design a garden room (well Billiard Room really) to go at the bottom of my garden.  It will be a simple wooden structure, basically a large shed on a proper concrete slab, and insulated.  It must be properly dry and to be usable it will need some insulation.  

 

My plan instead of buying Kingspan or mineral wool or whatever, is simply to use three inch Poplar which I have started milling for the purpose.  My logic is as follows:

 

1) Pop is a cheap timber and I had ideal logs lying around which I can spare.

 

2) As it is a very light timber I believe it will have a fairly good insulation value.

 

3) By using Actual boards of solid wood as the insulation, if I do it neatly I do not then need to face them with yet more boards.  They will be fitted vertically between the uprights of the walls.  There will be no bracing as I am relying on the Pop to effectively do that for me. 

 

The Pop is starting to air dry, and if need be I will pop it in the kiln so it is properly dried before fitting.

 

I am sure I am not the first person to try this sort of approach.  No exciting pics yet, just a pop log on the mill today.

 

Half milled on the Lucas mill as it was nearly three foot diameter, then finished off on the bandmill.

[se7enthdevil]

i don't see why it should not do the job but you will need to prevent it from rotting...

 

what size table are you setting up?

 

[Big J]

Keep in mind that the shrinkage in drying is huge. I did a mezzanine at my old sawmill in green poplar. 30cm wide floor boards, fitted butted right up to each other. By the time it dried (which was only a few weeks), I had 2cm gaps between all the boards.

 

Personally, I wouldn't use poplar in this capacity. It's just too unstable, and with it's hygroscopic tendencies, it'll swell and contract a lot depending on RH. On the flipside, this is great for indoor air quality, but it's a pain to work with.

[Squaredy]

52 minutes ago, se7enthdevil said:

i don't see why it should not do the job but you will need to prevent it from rotting...

 

what size table are you setting up?

 

Well the outer skin will be Doug Fir cladding with a breathable membrane under.  The bottom line is I have to keep the building dry for the purposes of Snooker table etc.  With a proper membrane in concrete slab and other details I don't think this will be a problem.

 

I have discovered that the cheapest good quality second hand snooker tables these days are full size ones.  I have to have a chat with the neighbour this weekend and see if he is happy for me to go right up to the boundary.  If he is OK with that it will be full size.  Dream come true...

[Squaredy]

45 minutes ago, Big J said:

Keep in mind that the shrinkage in drying is huge. I did a mezzanine at my old sawmill in green poplar. 30cm wide floor boards, fitted butted right up to each other. By the time it dried (which was only a few weeks), I had 2cm gaps between all the boards.

 

Personally, I wouldn't use poplar in this capacity. It's just too unstable, and with it's hygroscopic tendencies, it'll swell and contract a lot depending on RH. On the flipside, this is great for indoor air quality, but it's a pain to work with.

Ah but Jonathon this is Wales not damp Scotland!  I will kiln it if necessary before installation, and then leave a little gap like a boatbuilder planking a boat, to allow for a little movement.  But the plan is it will be quite a controlled climate in there - after all it will have a snooker table in!  If I need to run a de-humidifier during damp cold weather I will.

 

I will update this thread as work progresses...might be this side of Christmas....might not!

[Big J]

27 minutes ago, Squaredy said:

Ah but Jonathon this is Wales not damp Scotland!  I will kiln it if necessary before installation, and then leave a little gap like a boatbuilder planking a boat, to allow for a little movement.  But the plan is it will be quite a controlled climate in there - after all it will have a snooker table in!  If I need to run a de-humidifier during damp cold weather I will.

 

I will update this thread as work progresses...might be this side of Christmas....might not!

Wales is renowned for rain! ?

 

Just my experience with poplar. We used it a lot as a cheap and cheerful timber, but it's troublesome. It makes marvellous firewood, and that's what I'd recommend using it for   

[se7enthdevil]

13 hours ago, Squaredy said:

I have discovered that the cheapest good quality second hand snooker tables these days are full size ones.  I have to have a chat with the neighbour this weekend and see if he is happy for me to go right up to the boundary.  If he is OK with that it will be full size.  Dream come true...

it's in my dreams somewhere to have a full sized table too one day as i love watching and playing. 

 

as a woodturner though the table frames are a good source of genuine mahogany. i must have s dozen tables in bits consisting of legs and sides in my containers.

[Squaredy]

2 minutes ago, se7enthdevil said:

it's in my dreams somewhere to have a full sized table too one day as i love watching and playing. 

 

as a woodturner though the table frames are a good source of genuine mahogany. i must have s dozen tables in bits consisting of legs and sides in my containers.

I still have the brochures I sent for in the early eighties when I was at secondary school, I got the brochures from all the UK manufacturers I could find and pored over them for hours.  I have no idea why really, I had no money or space but there we are!

 

Keep an eye on this thread Steve, you are not too far from me and I daresay there will be invitation evenings for wood people eventually....

[Woodworks]

As J says you will end up with lots of gaps due to seasonal movement pretty much negation the insulation value of the wood which is not great to start with.

 

Might be of interest https://www.energy.gov/energysaver/types-homes/energy-efficiency-log-homes

Edited May 16, 2020 by Woodworks

[Squaredy]

25 minutes ago, Woodworks said:

As J says you will end up with lots of gaps due to seasonal movement pretty much negation the insulation value of the wood which is not great to start with.

 

Might be of interest https://www.energy.gov/energysaver/types-homes/energy-efficiency-log-homes

Most insulators work I believe by trapping air.  On this basis I would expect Poplar to be an excellent insulator, but with the advantage that it is not plastic based, so much nicer to handle and install and ultimately highly sustainable. 

 

The image below is Poplar viewed through an electron microscope.  Slight gaps will not be a big issue (I hope) as they will be caulked like a boat hull, so allowing slight movement.